Nat Plants , IF:13.256 , 2019 Nov , V5 (11) : P1114-1119 doi: 10.1038/s41477-019-0542-5
PIN-driven auxin transport emerged early in streptophyte evolution.
Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic.; The Czech Academy of Sciences, Institute of Experimental Botany, Prague, Czech Republic.; CEITEC, Masaryk University, Mendel Centre for Genomics and Proteomics of Plants Systems, Brno, Czech Republic.; Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, Umea, Sweden.; Department of Chemical Biology and Genetics, Centre of the Region Hana for Biotechnological and Agricultural Research, Faculty of Science, Palacky University, Olomouc, Czech Republic.; IST Austria, Klosterneuburg, Austria.; School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.; IST Austria, Klosterneuburg, Austria. jiri.friml@ist.ac.at.
PIN-FORMED (PIN) transporters mediate directional, intercellular movement of the phytohormone auxin in land plants. To elucidate the evolutionary origins of this developmentally crucial mechanism, we analysed the single PIN homologue of a simple green alga Klebsormidium flaccidum. KfPIN functions as a plasma membrane-localized auxin exporter in land plants and heterologous models. While its role in algae remains unclear, PIN-driven auxin export is probably an ancient and conserved trait within streptophytes.
PMID: 31712756
Sci Adv , IF:13.116 , 2019 Nov , V5 (11) : Peaaw6787 doi: 10.1126/sciadv.aaw6787
Anchorene is a carotenoid-derived regulatory metabolite required for anchor root formation in Arabidopsis.
King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division, The BioActives Lab, Thuwal 23955-6900, Saudi Arabia.; Department of Biology and Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA.; King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division, Red Sea Research Center, Thuwal 23955-6900, Saudi Arabia.; King Abdullah University of Science and Technology, Division of Biological and Environmental Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia.; King Abdullah University of Science and Technology (KAUST), Core Lab, Thuwal 23955-6900, Saudi Arabia.; RWTH Aachen University, Institute of Organic Chemistry, 52074 Aachen, Germany.; King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, KAUST Catalysis Center, Thuwal 23955-6900, Saudi Arabia.
Anchor roots (ANRs) arise at the root-shoot junction and are the least investigated type of Arabidopsis root. Here, we show that ANRs originate from pericycle cells in an auxin-dependent manner and a carotenogenic signal to emerge. By screening known and assumed carotenoid derivatives, we identified anchorene, a presumed carotenoid-derived dialdehyde (diapocarotenoid), as the specific signal needed for ANR formation. We demonstrate that anchorene is an Arabidopsis metabolite and that its exogenous application rescues the ANR phenotype in carotenoid-deficient plants and promotes the growth of normal seedlings. Nitrogen deficiency resulted in enhanced anchorene content and an increased number of ANRs, suggesting a role of this nutrient in determining anchorene content and ANR formation. Transcriptome analysis and treatment of auxin reporter lines indicate that anchorene triggers ANR formation by modulating auxin homeostasis. Together, our work reveals a growth regulator with potential application to agriculture and a new carotenoid-derived signaling molecule.
PMID: 31807696
Nat Commun , IF:12.121 , 2019 Nov , V10 (1) : P5093 doi: 10.1038/s41467-019-13074-9
WUSCHEL acts as an auxin response rheostat to maintain apical stem cells in Arabidopsis.
Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, D-69120, Heidelberg, Germany.; Vienna Biocenter (VBC), Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030, Vienna, Austria.; Laboratoire Reproduction et Developpement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France.; Department of Developmental Physiology, Centre for Organismal Studies, Heidelberg University, D-69120, Heidelberg, Germany.; Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, D-69120, Heidelberg, Germany. jlohmann@meristemania.org.
To maintain the balance between long-term stem cell self-renewal and differentiation, dynamic signals need to be translated into spatially precise and temporally stable gene expression states. In the apical plant stem cell system, local accumulation of the small, highly mobile phytohormone auxin triggers differentiation while at the same time, pluripotent stem cells are maintained throughout the entire life-cycle. We find that stem cells are resistant to auxin mediated differentiation, but require low levels of signaling for their maintenance. We demonstrate that the WUSCHEL transcription factor confers this behavior by rheostatically controlling the auxin signaling and response pathway. Finally, we show that WUSCHEL acts via regulation of histone acetylation at target loci, including those with functions in the auxin pathway. Our results reveal an important mechanism that allows cells to differentially translate a potent and highly dynamic developmental signal into stable cell behavior with high spatial precision and temporal robustness.
PMID: 31704928
Mol Plant , IF:12.084 , 2019 Nov , V12 (11) : P1499-1514 doi: 10.1016/j.molp.2019.09.001
A Molecular Framework for the Control of Adventitious Rooting by TIR1/AFB2-Aux/IAA-Dependent Auxin Signaling in Arabidopsis.
Umea Plant Science Centre, Department of Plant Physiology, Umea University, 90736 Umea, Sweden.; Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universite Paris-Saclay, 78000 Versailles, France.; Umea Plant Science Centre, Department of Plant Physiology, Umea University, 90736 Umea, Sweden; Department of Biology, Faculty of Science, Shahid Bahonar University, Kerman, Iran.; Laboratory of Growth Regulators, Faculty of Science, Palacky University and Institute of Experimental Botany, The Czech Academy of Sciences, 78371 Olomouc, Czech Republic; Umea Plant Science Centre, Department of Forest Genetics and Physiology, Swedish Agriculture University, 90183 Umea, Sweden.; Centre de Ressources Regionales en Biologie Moleculaire (CRRBM), Universite de Picardie Jules Verne, 80039 Amiens, France.; Umea Plant Science Centre, Department of Plant Physiology, Umea University, 90736 Umea, Sweden; Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universite Paris-Saclay, 78000 Versailles, France. Electronic address: catherine.bellini@umu.se.
In Arabidopsis thaliana, canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR (ARF) family that interact with auxin/indole acetic acid repressors (Aux/IAAs), which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR1/AUXIN-SIGNALLING F-BOX (TIR1/AFB) proteins. Different combinations of co-receptors drive specific sensing outputs, allowing auxin to control a myriad of processes. ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate, but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown. Here, using loss-of-function mutants we show that three Aux/IAA genes, IAA6, IAA9, and IAA17, act additively in the control of adventitious root (AR) initiation. These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development. We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid (JA) biosynthesis and conjugation, as several JA biosynthesis genes are up-regulated in the tir1-1 mutant. These results lead us to propose that in the presence of auxin, TIR1 and AFB2 form specific sensing complexes with IAA6, IAA9, and/or IAA17 to modulate JA homeostasis and control AR initiation.
PMID: 31520787
Plant Physiol , IF:6.902 , 2019 Nov , V181 (3) : P1360-1370 doi: 10.1104/pp.19.00833
Downregulation of PHYTOCHROME-INTERACTING FACTOR 4 Influences Plant Development and Fruit Production.
Departamento de Botanica, Instituto de Biociencias, Universidade de Sao Paulo, 05508-090, Sao Paulo, SP, Brazil.; Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, 05508-000, Sao Paulo, SP, Brazil.; Escola Superior de Agricultura 'Luiz de Queiroz', Universidade de Sao Paulo, 13418-900, Piracicaba, SP, Brazil.; Departamento de Botanica, Instituto de Biociencias, Universidade de Sao Paulo, 05508-090, Sao Paulo, SP, Brazil mmrossi@usp.br.
Plant development is highly dependent on the ability to perceive and cope with environmental changes. In this context, PIF proteins are key players in the cellular hub controlling responses to fluctuating light and temperature conditions. Reports in various plant species show that manipulation of the PIF4 level affects important agronomical traits. In tomato (Solanum lycopersicum), SlPIF1a and SlPIF3 regulate fruit nutraceutical composition. However, the wider role of this protein family, and the potential of their manipulation for the improvement of other traits, has not been explored. Here we report the effects of constitutive silencing of tomato SlPIF4 on whole-plant physiology and development. Ripening anticipation and higher carotenoid levels observed in SlPIF4-silenced fruits revealed a redundant role of SlPIF4 in the accumulation of nutraceutical compounds. Furthermore, silencing triggered a significant reduction in plant size, flowering, fruit yield, and fruit size. This phenotype was most likely caused by reduced auxin levels and altered carbon partitioning. Impaired thermomorphogenesis and delayed leaf senescence were also observed in silenced plants, highlighting the functional conservation of PIF4 homologs in angiosperms. Overall, this work improves our understanding of the role of PIF proteins-and light signaling-in metabolic and developmental processes that affect yield and composition of fleshy fruits.
PMID: 31519788
Sci Total Environ , IF:6.551 , 2019 Nov , V693 : P133650 doi: 10.1016/j.scitotenv.2019.133650
Facilitating effects of plant hormones on biomass production and nutrients removal by Tetraselmis cordiformis for advanced sewage treatment and its mechanism.
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China.; Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China. Electronic address: zhoujiantt@cqu.edu.cn.
Advanced sewage treatment by microalgae is regarded as a promising method for addressing eutrophication. To improve sewage treatment, three kinds of plant hormones including auxin (indole-3-acetic acid, IAA), cytokinin (Zeatin), and brassinosteroid, were chosen to measure the influence of plant hormones on nitrogen and phosphorus removal by Tetraselmis cordiformis and to analyze their mechanisms, including photosynthesis, nutrient metabolism, and gene transcription. The results indicated that the maximal removal efficiencies of total nitrogen and phosphate by T. cordiformis were elevated by the plant hormones by 184.3% and 53.2%, respectively. The chlorophyll a content was increased by 1.1 times by the plant hormones in comparison with the control. Moreover, after being stimulated by plant hormones, the activities of nitrate reductase (NR) and glutamine synthetase (GS) increased by 90.4% and 82.1%, respectively, in comparison with the control. Supplementation with plant hormones also significantly elevated the mRNA expression level of GS-related gene by 30.9%. This study demonstrated that plant hormones could significantly promote the nutrient removal of microalgae for sewage treatment in artificial laboratory conditions and provided theoretical support for its further practical full-scale application under variable conditions.
PMID: 31377356
Plant J , IF:6.141 , 2019 Nov , V100 (3) : P562-571 doi: 10.1111/tpj.14469
Transforming compound leaf patterning by manipulating REVOLUTA in Medicago truncatula.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China.; Noble Research Institute, LLC, Ardmore, OK, 73401, USA.; Hunan Provincial Key Laboratory of Phytohormones, Hunan Agricultural University, Changsha, Hunan, 410128, China.; Grassland Agri-Husbandry Research Center, College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China.
Leaves are derived from the shoot apical meristem with three distinct axes: dorsoventral, proximodistal and mediolateral. Different regulators are involved in the establishment of leaf polarity. Members of the class III homeodomain-leucine zipper (HD-ZIPIII) gene family are critical players in the determination of leaf adaxial identity mediated by microRNA165/166. However, their roles in compound leaf development are still unclear. By screening of a retrotransposon-tagged mutant population of the model legume plant Medicago truncatula, a mutant line with altered leaflet numbers was isolated and characterized. Mutant leaves partially lost their adaxial identity. Leaflet numbers in the mutant were increased along the proximodistal axis, showing pinnate pentafoliate leaves in most cases, in contrast to the trifoliate leaves of the wild type. Detailed characterization revealed that a lesion in a HD-ZIPIII gene, REVOLUTA (MtREV1), resulted in the defects of the mutant. Overexpression of MtMIR166-insensitive MtREV1 led to adaxialized leaves and ectopic leaflets along the dorsoventral axis. Accompanying the abnormal leaf patterning, the free auxin content was affected. Our results demonstrate that MtREV1 plays a key role in determination of leaf adaxial-abaxial polarity and compound leaf patterning, which is associated with proper auxin homeostasis.
PMID: 31350797
Plant J , IF:6.141 , 2019 Nov , V100 (3) : P627-640 doi: 10.1111/tpj.14474
Transcription of specific auxin efflux and influx carriers drives auxin homeostasis in tobacco cells.
The Czech Academy of Sciences, Institute of Experimental Botany, Rozvojova 263, 165 02 Prague 6, Czech Republic.; Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic.
Auxin concentration gradients are informative for the transduction of many developmental cues, triggering downstream gene expression and other responses. The generation of auxin gradients depends significantly on cell-to-cell auxin transport, which is supported by the activities of auxin efflux and influx carriers. However, at the level of individual plant cell, the co-ordination of auxin efflux and influx largely remains uncharacterized. We addressed this issue by analyzing the contribution of canonical PIN-FORMED (PIN) proteins to the carrier-mediated auxin efflux in Nicotiana tabacum L., cv. Bright Yellow (BY-2) tobacco cells. We show here that a majority of canonical NtPINs are transcribed in cultured cells and in planta. Cloning of NtPIN genes and their inducible overexpression in tobacco cells uncovered high auxin efflux activity of NtPIN11, accompanied by auxin starvation symptoms. Auxin transport parameters after NtPIN11 overexpression were further assessed using radiolabelled auxin accumulation and mathematical modelling. Unexpectedly, these experiments showed notable stimulation of auxin influx, which was accompanied by enhanced transcript levels of genes for a specific auxin influx carrier and by decreased transcript levels of other genes for auxin efflux carriers. A similar transcriptional response was observed upon removal of auxin from the culture medium, which resulted in decreased auxin efflux. Overall, our results revealed an auxin transport-based homeostatic mechanism for the maintenance of endogenous auxin levels. OPEN RESEARCH BADGES: This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at http://osf.io/ka97b/.
PMID: 31349380
Plant J , IF:6.141 , 2019 Nov , V100 (3) : P536-548 doi: 10.1111/tpj.14456
Reactive oxygen species and reactive carbonyl species constitute a feed-forward loop in auxin signaling for lateral root formation.
The United Graduate School of Agriculture, Tottori University, Koyama-Cho Minami 4-101, Tottori, 680-8550, Japan.; Department of Horticulture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, 1706, Bangladesh.; Department of Biology, Graduate School of Science, Kobe University, Rokkodai 1-1, Nada-ku, Kobe, 657-8501, Japan.; Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan.; Faculty of Agriculture, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.; Science Research Center, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.; Graduate School of Sciences and Technologies for Innovation, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.
In auxin-stimulated roots, production of reactive oxygen species (ROS) via the hormone-induced activation of respiratory burst oxidase homologous NADPH oxidases facilitates lateral root (LR) formation. In this study, in order to verify that ROS can modulate auxin signaling, we examined the involvement of the lipid peroxide-derived agents known as reactive carbonyl species (RCS) in LR formation. When auxin was added to Arabidopsis thaliana roots, the levels of RCS, for example acrolein, 4-hydroxynonenal and crotonaldehyde, were increased prior to LR formation. Addition of the carbonyl scavenger carnosine suppressed auxin-induced LR formation. Addition of RCS to the roots induced the expression of the auxin-responsive DR5 promoter and the TIR1, IAA14, ARF7, LBD16 and PUCHI genes and facilitated LR formation without increasing the endogenous auxin level. DR5 and LBD16 were activated in the LR primordia. The auxin signaling-deficient mutants arf7 arf19 and slr-1 did not respond - and tir1 afb2 appeared to show a poor response - to RCS. When given to the roots RCS promoted the disappearance of the AXR3NT-GUS fusion protein, i.e. the degradation of the auxin/indole-3-acetic acid protein, as did auxin. These results indicate that the auxin-induced production of ROS and their downstream products RCS modulate the auxin signaling pathway in a feed-forward manner. RCS are key agents that connect the ROS signaling and the auxin signaling pathways.
PMID: 31306517
J Exp Bot , IF:5.908 , 2019 Nov , V70 (21) : P6293-6304 doi: 10.1093/jxb/erz392
cis-Cinnamic acid is a natural plant growth-promoting compound.
Ghent University, Department of Plant Biotechnology and Bioinformatics, Gent, Belgium.; VIB Center for Plant Systems Biology, VIB, Technologiepark 927, Gent, Belgium.; Ghent University, Department of Biology, Gent, Belgium.
Agrochemicals provide vast potential to improve plant productivity, because they are easy to implement at low cost while not being restricted by species barriers as compared with breeding strategies. Despite the general interest, only a few compounds with growth-promoting activity have been described so far. Here, we add cis-cinnamic acid (c-CA) to the small portfolio of existing plant growth stimulators. When applied at low micromolar concentrations to Arabidopsis roots, c-CA stimulates both cell division and cell expansion in leaves. Our data support a model explaining the increase in shoot biomass as the consequence of a larger root system, which allows the plant to explore larger areas for resources. The requirement of the cis-configuration for the growth-promoting activity of CA was validated by implementing stable structural analogs of both cis- and trans-CA in this study. In a complementary approach, we used specific light conditions to prevent cis/trans-isomerization of CA during the experiment. In both cases, the cis-form stimulated plant growth, whereas the trans-form was inactive. Based on these data, we conclude that c-CA is an appealing lead compound representing a novel class of growth-promoting agrochemicals. Unraveling the underlying molecular mechanism could lead to the development of innovative strategies for boosting plant biomass.
PMID: 31504728
J Exp Bot , IF:5.908 , 2019 Nov , V70 (21) : P6229-6244 doi: 10.1093/jxb/erz373
AtNSE1 and AtNSE3 are required for embryo pattern formation and maintenance of cell viability during Arabidopsis embryogenesis.
State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
Embryogenesis is an essential process during seed development in higher plants. It has previously been shown that mutation of the Arabidopsis non-SMC element genes AtNSE1 or AtNSE3 leads to early embryo abortion, and their proteins can interact with each other directly. However, the crucial regions of these proteins in this interaction and how the proteins are cytologically involved in Arabidopsis embryo development are unknown. In this study, we found that the C-terminal including the Ring-like motif of AtNSE1 can interact with the N-terminal of AtNSE3, and only the Ring-like motif is essential for binding with three alpha motifs of AtNSE2 (homologous to AtMMS21). Using genetic assays and by analysing molecular markers of cell fate decisions (STM, WOX5, and WOX8) in mutant nse1 and nse3 embryos, we found that AtNSE1 and AtNSE3 work non-redundantly in early embryo development, and that differentiation of the apical meristem and the hypophysis fails in the mutants, which have disrupted auxin transportation and responses. However, the upper cells of the suspensor in the mutants seem to have proper embryo cell identity. Cytological examination showed that cell death occurred from the early embryo stage, and that vacuolar programmed cell death and necrosis in the nse1 and nse3 mutant embryos led to ovule abortion. Thus, AtNSE1 and AtNSE3 are essential for maintaining cell viability and growth during early embryogenesis. Our results improve our understanding of the functions of SMC5/6 complex in early embryogenesis in Arabidopsis.
PMID: 31408172
J Integr Plant Biol , IF:4.885 , 2019 Nov , V61 (11) : P1114-1120 doi: 10.1111/jipb.12853
The 35S promoter-driven mDII auxin control sensor is uniformly distributed in leaf primordia.
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
By using mechanical and optical sectioning of DII/mDII and R2D2 auxin sensors, we reconfirmed the presence of asymmetric auxin signaling in leaf primordia. We also showed that the imaging data reported by Bhatia et al. (2019) may suffer from artefacts, and that their analysis was artificially biased due to an arbitrary domain demarcation.
PMID: 31267663
J Integr Plant Biol , IF:4.885 , 2019 Nov , V61 (11) : P1134-1150 doi: 10.1111/jipb.12759
Genome-wide association study of callus induction variation to explore the callus formation mechanism of rice.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430071, China.
Rice (Oryza sativa) is one of the most widely cultivated food crops, worldwide. Tissue culture is extensively used in rice breeding and functional genome research. The ability to induce callus determines whether a particular rice variety can be subjected to tissue culture and Agrobacterium-mediated transformation. Over the past two decades, many quantitative trait loci (QTLs) related to callus induction traits have been identified; however, individual genes associated with rice callus induction have not been reported. In this study, we characterized three callus-induction traits in a global collection of 510 rice accessions. A genome-wide association study of the rice population in its entirety as well as subpopulations revealed 21 significant loci located in rice callus induction QTLs. We identified three candidate callus induction genes, namely CRL1, OsBMM1, and OsSET1, which are orthologs of Arabidopsis LBD17/LBD29, BBM, and SWN, respectively, which are known to affect callus formation. Furthermore, we predicted that 14 candidate genes might be involved in rice callus induction and showed that RNA interference (RNAi)-mediated disruption of OsIAA10 inhibited callus formation on tissue culture medium. Embryo growth in the OsIAA10 RNAi line was not inhibited by synthetic auxin (2,4-D) treatment, suggesting that OsIAA10 may perceive auxin and activate the expression of downstream genes, such as CRL1, to induce callus formation. The significant loci and candidate genes identified here may provide insight into the mechanism underlying callus formation in rice.
PMID: 30565430
Int J Mol Sci , IF:4.556 , 2019 Nov , V20 (22) doi: 10.3390/ijms20225741
SiMYB3 in Foxtail Millet (Setaria italica) Confers Tolerance to Low-Nitrogen Stress by Regulating Root Growth in Transgenic Plants.
National Key Facility for Crop Genetic Resources and Genetic Improvement, Key Laboratory of Crop Genetics and Breeding, Ministry of Agriculture/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; Rice Research Institute, Jiangxi Academy of Agricultural Sciences/ Rice National Engineering Laboratory, Nanchang 330200, China.; Xiangyang Academy of Agricultural Sciences, Xiangyang 441057, China.
Foxtail millet (Setaria italica), which originated in China, has a strong tolerance to low nutrition stresses. However, the mechanism of foxtail millet tolerance to low-nitrogen stress is still unknown. In this study, the transcriptome of foxtail millet under low-nitrogen stress was systematically analyzed. Expression of 1891 genes was altered, including 1318 up-regulated genes and 573 down-regulated genes. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis revealed that 3% of these genes were involved in membrane transport and 5% were involved in redox processes. There were 74 total transcription factor (TF) genes in the DEGs (differentially expressed genes), and MYB-like transcription factors accounted for one-third (25) of the TF genes. We systematically analyzed the characteristics, expression patterns, chromosome locations, and protein structures of 25 MYB-like genes. The analysis of gene function showed that Arabidopsis and rice overexpressing SiMYB3 had better root development than WT under low-nitrogen stress. Moreover, EMSA results showed that SiMYB3 protein could specifically bind MYB elements in the promoter region of TAR2, an auxin synthesis related gene and MYB3-TAR2 regulate pair conserved in rice and foxtail millet. These results suggested that SiMYB3 can regulate root development by regulating plant root auxin synthesis under low-nitrogen conditions.
PMID: 31731735
iScience , IF:4.447 , 2019 Nov , V21 : P458-473 doi: 10.1016/j.isci.2019.10.043
Genetic Loci Associated with Early Salt Stress Responses of Roots.
Laboratory of Plant Physiology, Plant Sciences Group, Wageningen University and Research, 6708PB Wageningen, the Netherlands; Plant Physiology, Swammerdam Institute of Life Sciences, University of Amsterdam, 1098XH Amsterdam, the Netherlands.; Laboratory of Plant Physiology, Plant Sciences Group, Wageningen University and Research, 6708PB Wageningen, the Netherlands.; Plant Physiology, Swammerdam Institute of Life Sciences, University of Amsterdam, 1098XH Amsterdam, the Netherlands.; Department of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, 23955-6900 Thuwal-Jeddah, Kingdom of Saudi Arabia.; Laboratory of Plant Physiology, Plant Sciences Group, Wageningen University and Research, 6708PB Wageningen, the Netherlands. Electronic address: christa.testerink@wur.nl.
Salinity is a devastating abiotic stress accounting for major crop losses yearly. Plant roots can strikingly grow away from high-salt patches. This response is termed halotropism and occurs through auxin redistribution in roots in response to a salt gradient. Here, a natural variation screen for the early and NaCl-specific halotropic response of 333 Arabidopsis accessions revealed quantitative differences in the first 24 h. These data were successfully used to identify genetic components associated with the response through Genome-Wide Association Study (GWAS). Follow-up characterization of knockout mutants in Col-0 background confirmed the role of transcription factor WRKY25, cation-proton exchanger CHX13, and a gene of unknown function DOB1 (Double Bending 1) in halotropism. In chx13 and dob1 mutants, ion accumulation and shoot biomass under salt stress were also affected. Thus, our GWAS has identified genetic components contributing to main root halotropism that provide insight into the genetic architecture underlying plant salt responses.
PMID: 31707259
Physiol Plant , IF:4.148 , 2019 Nov , V167 (3) : P433-446 doi: 10.1111/ppl.12918
Cold- and menthol-evoked membrane potential changes in the moss Physcomitrella patens: influence of ion channel inhibitors and phytohormones.
Department of Biophysics, Institute of Biology and Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033 Lublin, Poland.
Microelectrode measurements carried out on leaf cells from Physcomitrella patens revealed that a sudden temperature drop and application of menthol evoked two types of different-shaped membrane potential changes. Cold stimulation evoked spike-type responses. Menthol depolarized the cell membrane with different rates. When it reached above 1 mV s(-1) , the full response was recorded. Characteristic for the full responses was also a few-minute plateau of the membrane potential recorded after depolarization. The influence of inhibitors of calcium channels (5 mM Gd(3+) ), potassium channels (5 mM Ba(2+) ), chloride channels (200 muM Zn(2+) , 50 muM niflumic acid) and proton pumps (10 muM DES), an activator of calcium release from intracellular stores (Sr(2+) ), calcium chelation (by 400 muM EGTA) and phytohormones (50 muM auxin, 50 muM abscisic acid (ABA), 500 muM salicylic acid) on cold- and menthol-evoked responses was tested. Both responses are different in respect to the ion mechanism: cold-evoked depolarizations were influenced by Ba(2+) and DES; in turn, menthol-evoked potential changes were most effectively blocked by Zn(2+) . Moreover, the effectiveness of menthol in generation of full responses was reduced after administration of auxin or ABA, i.e. phytohormones known for their participation in responses to cold and regulation of proton pumps. The effects of DES indicated that one of the main conditions for generation of menthol-evoked responses is inhibition of the proton pump activity. Our results indicate that perception of cold and menthol by plants proceeds in different ways due to the differences in ionic mechanism and hormone dependence of cold- and menthol-evoked responses.
PMID: 30629304
Physiol Plant , IF:4.148 , 2019 Nov , V167 (3) : P330-351 doi: 10.1111/ppl.12894
Transcriptome profiles of soybean leaves and roots in response to zinc deficiency.
College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Zinc (Zn) deficiency is a widespread agricultural problem in arable soils of the whole world. However, the molecular mechanisms underlying Zn-deficiency response are largely unknown. Here, we analyzed the transcriptomic profilings of soybean leaves and roots in response to Zn deficiency through Illumina's high-throughput RNA sequencing in order to understand the molecular basis of Zn-deficiency response in the plants. A total of 614 and 1011 gene loci were found to be differentially expressed in leaves and roots, respectively, and 88 loci were commonly found in both leaves and roots. Twelve differentially expressed genes (DEGs) were randomly selected for validation by quantitative reverse transcription polymerase chain reaction, and their fold changes were similar to those of RNA-seq. Gene ontology enrichment analysis showed that ion transport, nicotianamine (NA) biosynthetic process and queuosine biosynthetic process were enriched in the upregulated genes, while oxidation-reduction process and defense response were enriched in the downregulated genes. Among the DEGs, 20 DEGs are potentially involved in Zn homeostasis, including seven ZRT, IRT-related protein (ZIP) transporter genes, three NA synthase genes, and seven metallothionein genes; 40 DEGs are possibly involved in diverse hormonal signals such as auxin, cytokinin, ethylene and gibberellin; nine DEGs are putatively involved in calcium signaling; 85 DEGs are putative transcription factor genes. Nine DEGs were found to contain zinc-deficiency-response element in their promoter regions. These results could provide comprehensive insights into the soybean response to Zn deficiency and will be helpful for further elucidation of the molecular mechanisms of Zn-deficiency response and Zn-deficiency tolerance in plants.
PMID: 30536844
Biomolecules , IF:4.082 , 2019 Nov , V9 (12) doi: 10.3390/biom9120805
CSN5A Subunit of COP9 Signalosome Temporally Buffers Response to Heat in Arabidopsis.
School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 6997801, Israel.; The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 8499000, Israel.; Department of Bioengineering, University of Information Science and Technology (UIST) St. Paul, 6000 Ohrid, Macedonia.
The COP9 (constitutive photomorphogenesis 9) signalosome (CSN) is an evolutionarily conserved protein complex which regulates various growth and developmental processes. However, the role of CSN during environmental stress is largely unknown. Using Arabidopsis as model organism, we used CSN hypomorphic mutants to study the role of the CSN in plant responses to environmental stress and found that heat stress specifically enhanced the growth of csn5a-1 but not the growth of other hypomorphic photomorphogenesis mutants tested. Following heat stress, csn5a-1 exhibits an increase in cell size, ploidy, photosynthetic activity, and number of lateral roots and an upregulation of genes connected to the auxin response. Immunoblot analysis revealed an increase in deneddylation of CUL1 but not CUL3 following heat stress in csn5a-1, implicating improved CUL1 activity as a basis for the improved growth of csn5a-1 following heat stress. Studies using DR5::N7-VENUS and DII-VENUS reporter constructs confirm that the heat-induced growth is due to an increase in auxin signaling. Our results indicate that CSN5A has a specific role in deneddylation of CUL1 and that CSN5A is required for the recovery of AUX/IAA repressor levels following recurrent heat stress to regulate auxin homeostasis in Arabidopsis.
PMID: 31795414
Ann Bot , IF:4.005 , 2019 Nov , V124 (5) : P749-767 doi: 10.1093/aob/mcz100
Strigolactones and their crosstalk with other phytohormones.
Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Scottsville, South Africa.
BACKGROUND: Strigolactones (SLs) are a diverse class of butenolide-bearing phytohormones derived from the catabolism of carotenoids. They are associated with an increasing number of emerging regulatory roles in plant growth and development, including seed germination, root and shoot architecture patterning, nutrient acquisition, symbiotic and parasitic interactions, as well as mediation of plant responses to abiotic and biotic cues. SCOPE: Here, we provide a concise overview of SL biosynthesis, signal transduction pathways and SL-mediated plant responses with a detailed discourse on the crosstalk(s) that exist between SLs/components of SL signalling and other phytohormones such as auxins, cytokinins, gibberellins, abscisic acid, ethylene, jasmonates and salicylic acid. CONCLUSION: SLs elicit their control on physiological and morphological processes via a direct or indirect influence on the activities of other hormones and/or integrants of signalling cascades of other growth regulators. These, among many others, include modulation of hormone content, transport and distribution within plant tissues, interference with or complete dependence on downstream signal components of other phytohormones, as well as acting synergistically or antagonistically with other hormones to elicit plant responses. Although much has been done to evince the effects of SL interactions with other hormones at the cell and whole plant levels, research attention must be channelled towards elucidating the precise molecular events that underlie these processes. More especially in the case of abscisic acid, cytokinins, gibberellin, jasmonates and salicylic acid for which very little has been reported about their hormonal crosstalk with SLs.
PMID: 31190074
Ann Bot , IF:4.005 , 2019 Nov , V124 (6) : P1053-1066 doi: 10.1093/aob/mcz095
Role of auxin homeostasis and response in nitrogen limitation and dark stimulation of adventitious root formation in petunia cuttings.
Leibniz Institute of Vegetable and Ornamental Crops (IGZ), Erfurt, Germany.; Leibniz Institute of Plant Genetics and Crop Plant Research, Stadt Seeland, Germany.
BACKGROUND AND AIMS: Adventitious root (AR) formation in Petunia hybrida is inhibited by low nitrogen fertilization of stock plants but promoted by dark incubation of cuttings before planting. We investigated whether the plant hormone auxin is involved in nitrogen- and dark-mediated AR formation. METHODS: Concentrations of indole-3-acetic acid (IAA) and RNA accumulation of genes controlling auxin homeostasis and function were monitored in the stem base in response to high versus low nitrogen supply to stock plants and to temporal dark vs. light exposure of cuttings by use of GC-MS/MS, a petunia-specific microarray and quantitative RT-PCR. Auxin source capacity, polar auxin transport in cuttings and auxin concentration in the rooting zone were manipulated to investigate the functional contribution of auxin homeostasis and response to the effects of nitrogen fertilization and dark exposure on rooting. KEY RESULTS: The nitrogen content of cuttings had only a marginal effect on IAA concentration in the stem base. Dark incubation enhanced the accumulation of IAA in the stem base during AR induction independent of nitrogen level. Early IAA accumulation in the dark depended on the upper shoot as an auxin source and was enhanced after apical IAA supply. Dark exposure stimulated RNA accumulation of auxin-related genes. In particular, expression of Ph-PIN1 and of genes controlling auxin signalling, including Ph-IAA14, Ph-ARF8, Ph-ARF10 and Ph-SAUR14, was enhanced, while the latter four were repressed in nitrogen-limited cuttings, particularly in the dark. Dark stimulation of rooting depended on polar auxin transport. Basal auxin application partially substituted the effect of dark exposure on rooting, whereas the auxin response of AR formation was strongly depressed by nitrogen limitation. CONCLUSIONS: Increased auxin delivery from the upper shoot and enhanced auxin signalling in the stem base contribute to dark-stimulated AR formation, while nitrogen limitation inhibits AR formation downstream of the auxin signal.
PMID: 31181150
Ann Bot , IF:4.005 , 2019 Nov , V124 (6) : P969-978 doi: 10.1093/aob/mcz023
Potential involvement of root auxins in drought tolerance by modulating nocturnal and daytime water use in wheat.
Department of Agronomy and Plant Genetics, Upper Buford Circle, University of Minnesota, St. Paul, MN, USA.; Earth and Life Institute, Universite Catholique de Louvain, Louvain-la-Neuve, Belgium.
BACKGROUND AND AIMS: The ability of wheat genotypes to save water by reducing their transpiration rate (TR) at times of the day with high vapour pressure deficit (VPD) has been linked to increasing yields in terminal drought environments. Further, recent evidence shows that reducing nocturnal transpiration (TRN) could amplify water saving. Previous research indicates that such traits involve a root-based hydraulic limitation, but the contribution of hormones, particularly auxin and abscisic acid (ABA), has not been explored to explain the shoot-root link. In this investigation, based on physiological, genetic and molecular evidence gathered on a mapping population, we hypothesized that root auxin accumulation regulates whole-plant water use during both times of the day. METHODS: Eight double-haploid lines were selected from a mapping population descending from two parents with contrasting water-saving strategies and root hydraulic properties. These spanned the entire range of slopes of TR responses to VPD and TRN encountered in the population. We examined daytime/night-time auxin and ABA contents in the roots and the leaves in relation to hydraulic traits that included whole-plant TR, plant hydraulic conductance (KPlant), slopes of TR responses to VPD and leaf-level anatomical traits. KEY RESULTS: Root auxin levels were consistently genotype-dependent in this group irrespective of experiments and times of the day. Daytime root auxin concentrations were found to be strongly and negatively correlated with daytime TR, KPlant and the slope of TR response to VPD. Night-time root auxin levels significantly and negatively correlated with TRN. In addition, daytime and night-time leaf auxin and ABA concentrations did not correlate with any of the examined traits. CONCLUSIONS: The above results indicate that accumulation of auxin in the root system reduces daytime and night-time water use and modulates plant hydraulic properties to enable the expression of water-saving traits that have been associated with enhanced yields under drought.
PMID: 30918962
Ann Bot , IF:4.005 , 2019 Nov , V124 (6) : P903-915 doi: 10.1093/aob/mcy218
TaARF4 genes are linked to root growth and plant height in wheat.
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
BACKGROUND AND AIMS: Auxin response factors (ARFs) as transcription activators or repressors have important roles in plant growth and development, but knowledge about the functions of wheat ARF members is limited. A novel ARF member in wheat (Triticum aestivum), TaARF4, was identified, and its protein function, haplotype geographic distribution and allelic frequencies were investigated. METHODS: Tissue expression of TaARF4 was analysed by real-time PCR. Sub-cellular localization was performed using green fluorescent protein (GFP)-tagged TaARF4. Ectopic expression of TaARF4-A in arabidopsis was used to study its functions. Electrophoretic mobility shift assays (EMSAs), chromatin immunoprecipitation (ChIP) analyses and gene expression were performed to detect TaARF4 target genes. A dCAPS (derived cleaved amplified polymorphic sequence) marker developed from TaARF4-B was used to identify haplotypes and association analysis between haplotypes and agronomic traits. KEY RESULTS: TaARF4-A was constitutively expressed and its protein was localized in the nucleus. Ectopic expression of TaARF4-A in arabidopsis caused abscisic acid (ABA) insensitivity, shorter primary root length and reduced plant height (PH). Through expression studies and ChIP assays, TaARF4-A was shown to regulate HB33 expression which negatively responded to ABA, and reduced root length and plant height by repressing expression of Gretchen Hagen 3 (GH3) genes that in turn upregulated indole-3-acetic acid content in arabidopsis. Association analysis showed that TaARF4-B was strongly associated with PH and root depth at the tillering, jointing and grain fill stages. Geographic distribution and allelic frequencies suggested that TaARF4-B haplotypes were selected in Chinese wheat breeding programmes. An amino acid change (threonine to alanine) at position 158 might be the cause of phenotype variation in accessions possessing different haplotypes. CONCLUSIONS: Ectopic expression and association analysis indicate that TaARF4 may be involved in root length and plant height determination in wheat. This work is helpful for selection of wheat genotypes with optimal root and plant architecture.
PMID: 30590478
Sci Rep , IF:3.998 , 2019 Nov , V9 (1) : P17327 doi: 10.1038/s41598-019-51482-5
Molecular Characterization of Auxin Efflux Carrier- ABCB1 in hexaploid wheat.
Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164, USA.; Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164, USA. ksgill@wsu.edu.
Auxin is an important phytohormone that regulates response, differentiation, and development of plant cell, tissue, and organs. Along with its local production, long-distance transport coordinated by the efflux/influx membrane transporters is instrumental in plant development and architecture. In the present study, we cloned and characterized a wheat (Triticum aestivum) auxin efflux carrier ABCB1. The TaABCB1 was physically localized to the proximal 15% of the short arm of wheat homoeologous group 7 chromosomes. Size of the Chinese spring (CS) homoeologs genomic copies ranged from 5.3-6.2 kb with the 7A copy being the largest due to novel insertions in its third intron. The three homoeologous copies share 95-97% sequence similarity at the nucleotide, 98-99% amino acid, and overall Q-score of 0.98 at 3-D structure level. Though detected in all analyzed tissues, TaABCB1 predominantly expressed in the meristematic tissues likely due to the presence of meristem-specific activation regulatory element identified in the promoter region. RNAi plants of TaABCB1 gene resulted in reduced plant height and increased seed width. Promoter analysis revealed several responsive elements detected in the promoter region including that for different hormones as auxin, gibberellic acid, jasmonic acid and abscisic acid, light, and circadian regulated elements.
PMID: 31757978
Sci Rep , IF:3.998 , 2019 Nov , V9 (1) : P17030 doi: 10.1038/s41598-019-53229-8
Ubiquitin carboxyl-terminal hydrolases are required for period maintenance of the circadian clock at high temperature in Arabidopsis.
Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, D-50829, Cologne, Germany. hryosuke@icu.ac.jp.; Department of Natural Sciences, International Christian University, 3-10-2 Osawa, Mitaka, 181-8585, Tokyo, Japan. hryosuke@icu.ac.jp.; Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.; , Bayer Crop Science, 800 N Lindbergh Blvd, St Louis, Missouri, 63146, USA.; Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, D-50829, Cologne, Germany.; Plant Development Unit, Institute for Plant Biochemistry and Photosynthesis, Consejo Superior de Investigaciones Cientificas, Universidad de Sevilla, 49th Americo Vespucio Avenue, Sevilla, 41092, Spain.; Department of Natural Sciences, International Christian University, 3-10-2 Osawa, Mitaka, 181-8585, Tokyo, Japan.; Department of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, Missouri, 63130, USA.; Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, D-50829, Cologne, Germany. coupland@mpipz.mpg.de.
Protein ubiquitylation participates in a number of essential cellular processes including signal transduction and transcription, often by initiating the degradation of specific substrates through the 26S proteasome. Within the ubiquitin-proteasome system, deubiquitylating enzymes (DUBs) not only help generate and maintain the supply of free ubiquitin monomers, they also directly control functions and activities of specific target proteins by modulating the pool of ubiquitylated species. Ubiquitin carboxyl-terminal hydrolases (UCHs) belong to an enzymatic subclass of DUBs, and are represented by three members in Arabidopsis, UCH1, UCH2 and UCH3. UCH1 and UCH2 influence auxin-dependent developmental pathways in Arabidopsis through their deubiquitylation activities, whereas biological and enzymatic functions of UCH3 remain unclear. Here, we demonstrate that Arabidopsis UCH3 acts to maintain the period of the circadian clock at high temperatures redundantly with UCH1 and UCH2. Whereas single uch1, uch2 and uch3 mutants have weak circadian phenotypes, the triple uch mutant displays a drastic lengthening of period at high temperatures that is more extreme than the uch1 uch2 double mutant. UCH3 also possesses a broad deubiquitylation activity against a range of substrates that link ubiquitin via peptide and isopeptide linkages. While the protein target(s) of UCH1-3 are not yet known, we propose that these DUBs act on one or more factors that control period length of the circadian clock through removal of their bound ubiquitin moieties, thus ensuring that the clock oscillates with a proper period even at elevated temperatures.
PMID: 31745110
Sci Rep , IF:3.998 , 2019 Nov , V9 (1) : P16602 doi: 10.1038/s41598-019-53283-2
Time-coursed transcriptome analysis identifies key expressional regulation in growth cessation and dormancy induced by short days in Paulownia.
College of Forestry, Henan Agricultural University, Zhengzhou, Henan, 450002, China.; School of life science, Liaoning University, Shenyang, 110000, China.; Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.; College of Forestry, Henan Agricultural University, Zhengzhou, Henan, 450002, China. liuzh20@163.com.; Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China. xwwang@uga.edu.; Department of Genetics, University of Georgia, Athens, 30602, USA. xwwang@uga.edu.
Maintaining the viability of the apical shoot is critical for continued vertical growth in plants. Terminal shoot of tree species Paulownia cannot regrow in subsequent years. The short day (SD) treatment leads to apical growth cessation and dormancy. To understand the molecular basis of this, we further conducted global RNA-Seq based transcriptomic analysis in apical shoots to check regulation of gene expression. We obtained ~219 million paired-end 125-bp Illumina reads from five time-courses and de novo assembled them to yield 49,054 unigenes. Compared with the untreated control, we identified 1540 differentially expressed genes (DEGs) which were found to involve in 116 metabolic pathways. Expression of 87% of DEGs exhibited switch-on or switch-off pattern, indicating key roles in growth cessation. Most DEGs were enriched in the biological process of gene ontology categories and at later treatment stages. The pathways of auxin and circadian network were most affected and the expression of associated DEGs was characterised. During SD induction, auxin genes IAA, ARF and SAURs were down-regulated and circadian genes including PIF3 and PRR5 were up-regulated. PEPC in photosynthesis was constitutively upregulated, suggesting a still high CO2 concentrating activity; however, the converting CO2 to G3P in the Calvin cycle is low, supported by reduced expression of GAPDH encoding the catalysing enzyme for this step. This indicates a de-coupling point in the carbon fixation. The results help elucidate the molecular mechanisms for SD inducing dormancy and cessation in apical shoots.
PMID: 31719639
Sci Rep , IF:3.998 , 2019 Nov , V9 (1) : P16644 doi: 10.1038/s41598-019-52958-0
A plant biostimulant from the seaweed Ascophyllum nodosum (Sealicit) reduces podshatter and yield loss in oilseed rape through modulation of IND expression.
Brandon Bioscience, Centrepoint, Tralee, Co., Kerry, Ireland.; Plant Biostimulant Group, Shannon Applied Biotechnology Centre, Institute of Technology Tralee, Clash, Tralee, Co., Kerry, Ireland.; Department of Crop Genetics, John Innes Centre, Norwich Research Park, Colney, NR4 7UH Norfolk, Norwich, United Kingdom.; Plant Biostimulant Group, Shannon Applied Biotechnology Centre, Institute of Technology Tralee, Clash, Tralee, Co., Kerry, Ireland. shane.oconnell@staff.ittralee.ie.
The yield of podded crops such as oilseed rape (OSR) is limited by evolutionary adaptations of the plants for more efficient and successful seed dispersal for survival. These plants have evolved dehiscent dry fruits that shatter along a specifically developed junction at carpel margins. A number of strategies such as pod sealants, GMOs and hybrids have been developed to mitigate the impact of pod shatter on crop yield with limited success. Plant biostimulants have been shown to influence plant development. A challenge in plant biostimulant research is elucidating the mechanisms of action. Here we have focused on understanding the effect of an Ascophyllum nodosum based biostimulant (Sealicit) on fruit development and seed dispersal trait in Arabidopsis and OSR at genetic and physiological level. The results indicate that Sealicit is affecting the expression of the major regulator of pod shattering, INDEHISCENT, as well as disrupting the auxin minimum. Both factors influence the formation of the dehiscence zone and consequently reduce pod shattering. Unravelling the mode of action of this unique biostimulant provides data to support its effectiveness in reducing pod shatter and highlights its potential for growers to increase seed yield in a number of OSR varieties.
PMID: 31719578
Sci Rep , IF:3.998 , 2019 Nov , V9 (1) : P15973 doi: 10.1038/s41598-019-52421-0
Comparative gene expression profile analysis of ovules provides insights into Jatropha curcas L. ovule development.
Institute for Forest Resources and Environment of Guizhou / College of Forestry, Guizhou University, Guiyang, 550025, P.R. China. xg335300@aliyun.com.; Institute of Entomology, Guizhou University, Guiyang, Guizhou, P.R. China. xg335300@aliyun.com.; Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals of Guizhou University, Guiyang, Guizhou, P.R. China.; School of Life Science, Guizhou University, Guiyang, Guizhou, P.R. China.; Institute for Forest Resources and Environment of Guizhou / College of Forestry, Guizhou University, Guiyang, 550025, P.R. China.
Jatropha curcas, an economically important biofuel feedstock with oil-rich seeds, has attracted considerable attention among researchers in recent years. Nevertheless, valuable information on the yield component of this plant, particularly regarding ovule development, remains scarce. In this study, transcriptome profiles of anther and ovule development were established to investigate the ovule development mechanism of J. curcas. In total, 64,325 unigenes with annotation were obtained, and 1723 differentially expressed genes (DEGs) were identified between different stages. The DEG analysis showed the participation of five transcription factor families (bHLH, WRKY, MYB, NAC and ERF), five hormone signaling pathways (auxin, gibberellic acid (GA), cytokinin, brassinosteroids (BR) and jasmonic acid (JA)), five MADS-box genes (AGAMOUS-2, AGAMOUS-1, AGL1, AGL11, and AGL14), SUP and SLK3 in ovule development. The role of GA and JA in ovule development was evident with increases in flower buds during ovule development: GA was increased approximately twofold, and JA was increased approximately sevenfold. In addition, the expression pattern analysis using qRT-PCR revealed that CRABS CLAW and AGAMOUS-2 were also involved in ovule development. The upregulation of BR signaling genes during ovule development might have been regulated by other phytohormone signaling pathways through crosstalk. This study provides a valuable framework for investigating the regulatory networks of ovule development in J. curcas.
PMID: 31685957
Pest Manag Sci , IF:3.75 , 2019 Nov , V75 (11) : P3113-3121 doi: 10.1002/ps.5553
Hybrid-type strigolactone analogues derived from auxins.
Institute for Molecules and Materials, Cluster of Organic Chemistry, Radboud University, Nijmegen, the Netherlands.; Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Palacky University, Olomouc, Czech Republic.
BACKGROUND: Strigolactones (SLs) have a vast number of ecological implications because of the broad spectrum of their biological activities. Unfortunately, the limited availability of SLs restricts their applicability for the benefit of humanity and renders synthesis the only option for their production. However, the structural complexity of SLs impedes their economical synthesis, which is unfeasible on a large scale. Synthesis of SL analogues and mimics with a simpler structure, but with retention of bioactivity, is the solution to this problem. RESULTS: Here, we present eight new hybrid-type SL analogues derived from auxin, synthesized via coupling of auxin ester [ethyl 2-(1H-indol-3-yl)acetate] and of ethyl 2-phenylacetate with four D-rings (mono-, two di- and trimethylated). The new hybrid-type SL analogues were bioassayed to assess the germination activity of seeds of the parasitic weeds Striga hermonthica, Orobanche minor and Phelipanche ramosa using the classical method of counting germinated seeds and a colorimetric method. The bioassays revealed that analogues with a natural monomethylated D-ring had appreciable to good activity towards the three species and were the most active derivatives. By contrast, derivatives with the trimethylated D-ring showed no activity. The dimethylated derivatives (2,4-dimethyl and 3,4-dimethyl) were slightly active, especially towards P. ramosa. CONCLUSIONS: New hybrid-type analogues derived from auxins have been prepared. These analogues may be attractive as potential suicidal germination agents for parasitic weed control because of their ease of preparation and relevant bioactivity. (c) 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
PMID: 31317630
BMC Genomics , IF:3.594 , 2019 Nov , V20 (1) : P892 doi: 10.1186/s12864-019-6258-0
Genome-wide identification and transcriptome profiling reveal that E3 ubiquitin ligase genes relevant to ethylene, auxin and abscisic acid are differentially expressed in the fruits of melting flesh and stony hard peach varieties.
College of Horticulture, Henan Agricultural University, Zhengzhou, 450002, China.; Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou, 450002, China.; Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.; College of Horticulture, Henan Agricultural University, Zhengzhou, 450002, China. jcfeng@henau.edu.cn.; Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou, 450002, China. jcfeng@henau.edu.cn.
BACKGROUND: Ubiquitin ligases (E3) are the enzymes in the ubiquitin/26S proteasome pathway responsible for targeting proteins to the degradation pathway and play major roles in multiple biological activities. However, the E3 family and their functions are yet to be identified in the fruit of peach. RESULTS: In this study, genome-wide identification, classification and characterization of the E3 ligase genes within the genome of peach (Prunus persica) was carried out. In total, 765 E3 (PpE3) ligase genes were identified in the peach genome. The PpE3 ligase genes were divided into eight subfamilies according to the presence of known functional domains. The RBX subfamily was not detected in peach. The PpE3 ligase genes were not randomly distributed among the 8 chromosomes, with a greater concentration on the longer chromosomes. The primary mode of gene duplication of the PpE3 ligase genes was dispersed gene duplication (DSD). Four subgroups of the BTB subfamily never characterized before were newly identified in peach, namely BTBAND, BTBBL, BTBP and BTBAN. The expression patterns of the identified E3 ligase genes in two peach varieties that display different types of fruit softening (melting flesh, MF, and stony hard, SH) were analyzed at 4 different stages of ripening using Illumina technology. Among the 765 PpE3 ligase genes, 515 (67.3%) were expressed (FPKM > 1) in the fruit of either MF or SH during fruit ripening. In same-stage comparisons, 231 differentially expressed genes (DEGs) were identified between the two peach cultivars. The number of DEGs in each subfamily varied. Most DEGs were members of the BTB, F-box, U-box and RING subfamilies. PpE3 ligase genes predicted to be involved in ethylene, auxin, or ABA synthesis or signaling and DNA methylation were differentially regulated. Eight PpE3 ligase genes with possible roles in peach flesh texture and fruit ripening were discussed. CONCLUSIONS: The results of this study provide useful information for further understanding the functional roles of the ubiquitin ligase genes in peach. The findings also provide the first clues that E3 ligase genes may function in the regulation of peach ripening.
PMID: 31752682
BMC Genomics , IF:3.594 , 2019 Nov , V20 (1) : P812 doi: 10.1186/s12864-019-6176-1
Genome-wide analysis, transcription factor network approach and gene expression profile of GH3 genes over early somatic embryogenesis in Coffea spp.
Department of Chemistry, Federal University of Lavras, Lavras, MG, 37200000, Brazil.; Department of Chemistry, Federal University of Lavras, Lavras, MG, 37200000, Brazil. wesleypfm@hotmail.com.; Sugarcane Technology Center, Piracicaba, SP, 13400970, Brazil.; Department of Chemistry, Federal University of Lavras, Lavras, MG, 37200000, Brazil. luciano@ufla.br.
BACKGROUND: Coffee production relies on plantations with varieties from Coffea arabica and Coffea canephora species. The first, the most representative in terms of coffee consumption, is mostly propagated by seeds, which leads to management problems regarding the plantations maintenance, harvest and processing of grains. Therefore, an efficient clonal propagation process is required for this species cultivation, which is possible by reaching a scalable and cost-effective somatic embryogenesis protocol. A key process on somatic embryogenesis induction is the auxin homeostasis performed by Gretchen Hagen 3 (GH3) proteins through amino acid conjugation. In this study, the GH3 family members were identified on C. canephora genome, and by performing analysis related to gene and protein structure and transcriptomic profile on embryogenic tissues, we point a GH3 gene as a potential regulator of auxin homeostasis during early somatic embryogenesis in C. arabica plants. RESULTS: We have searched within the published C. canephora genome and found 17 GH3 family members. We checked the conserved domains for GH3 proteins and clustered the members in three main groups according to phylogenetic relationships. We identified amino acids sets in four GH3 proteins that are related to acidic amino acid conjugation to auxin, and using a transcription factor (TF) network approach followed by RT-qPCR we analyzed their possible transcriptional regulators and expression profiles in cells with contrasting embryogenic potential in C. arabica. The CaGH3.15 expression pattern is the most correlated with embryogenic potential and with CaBBM, a C. arabica ortholog of a major somatic embryogenesis regulator. CONCLUSION: Therefore, one out of the GH3 members may be influencing on coffee somatic embryogenesis by auxin conjugation with acidic amino acids, which leads to the phytohormone degradation. It is an indicative that this gene can serve as a molecular marker for coffee cells with embryogenic potential and needs to be further studied on how much determinant it is for this process. This work, together with future studies, can support the improvement of coffee clonal propagation through in vitro derived somatic embryos.
PMID: 31694532
Plant Sci , IF:3.591 , 2019 Nov , V288 : P110239 doi: 10.1016/j.plantsci.2019.110239
OsLUGL is involved in the regulating auxin level and OsARFs expression in rice (Oryza sativa L.).
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.; State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China. Electronic address: jiangling@njau.edu.cn.; State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China; National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China. Electronic address: wanjm@njau.edu.cn.
Specification of floral organ identity is critical for floral morphology and inflorescence architecture. Floral organ identity in plants is controlled by floral homeotic A/B/C/D/E-class genes. Although multiple genes regulate floral organogenesis, our understanding of the regulatory network remains fragmentary. Here, we characterized a rice floral organ gene KAIKOUXIAO (KKX), mutation of which produces an uncharacteristic open hull, abnormal seed and semi-sterility. KKX encodes a putative LEUNIG-like (LUGL) transcriptional regulator OsLUGL. OsLUGL is preferentially expressed in young panicles and its protein can interact with OsSEU, which functions were reported as an adaptor for LEUNIG. OsLUGL-OsSEU functions together as a transcriptional co-regulatory complex to control organ identity. SEP3 (such as OsMADS8) and AP1 (such as OsMADS18) serve as the DNA-binding partner of OsLUGL-OsSEU complex. Further studies indicated that OsMADS8 and OsMADS18 could bind to the promoter of OsGH3-8. The altered expression of OsGH3-8 might cause the increased auxin level and the decreased expression of OsARFs. Overall, our results demonstrate a possible pathway whereby OsLUGL-OsSEU-OsAP1-OsSEP3 complex as a transcriptional co-regulator by targeting the promoter of OsGH3-8, then affecting auxin level, OsARFs expression and thereby influencing floral development. These findings provide a valuable insight into the molecular functions of OsLUGL in rice floral development.
PMID: 31521225
Plant Sci , IF:3.591 , 2019 Nov , V288 : P110224 doi: 10.1016/j.plantsci.2019.110224
Ginseng-derived patatin-related phospholipase PgpPLAIIIbeta alters plant growth and lignification of xylem in hybrid poplars.
Department of Applied Plant Science, College of Agriculture and Life Science, Chonnam National University, Gwangju, 61186, Republic of Korea. Electronic address: jinhun92@naver.com.; Division of Forest Biotechnology, National Institute of Forest Science, Suwon, 441-847, Republic of Korea. Electronic address: baeek@korea.kr.; Division of Forest Biotechnology, National Institute of Forest Science, Suwon, 441-847, Republic of Korea. Electronic address: yichoi99@korea.kr.; Department of Applied Plant Science, College of Agriculture and Life Science, Chonnam National University, Gwangju, 61186, Republic of Korea. Electronic address: mpizlee@jnu.ac.kr.
Patatin-liked phospholipase A (pPLAs) are major lipid acyl hydrolases that participate in various biological functions in plant growth and development. Previously, a ginseng-derived pPLAIII homolog was reported to reduce lignin content in Arabidopsis. This led us to evaluate its possible usefulness as a biomass source in wood plant. Herein, we report that there are six members in the pPLAIII gene family in poplar. Overexpression of pPLAIIIbeta derived from ginseng resulted in a reduced plant height with radially expanded stem growth in hybrid poplars. Compared with the wild type (WT), the chlorophyll content was increased in the overexpression poplar lines, whereas the leaf size was smaller. The secondary cell wall structure in overexpression lines was also altered, exhibiting reduced lignification in the xylem. Two transcription factors, MYB92 and MYB152, which control lignin biosynthesis, were downregulated in the overexpression lines. The middle xylem of the overexpression line showed heavy thickening, making it thicker than the other xylem parts and the WT xylem, which rather could have been contributed by the presence of more cellulose in the selected surface area. Taken together, the results suggest that PgpPLAIIIbeta plays a role not only in cell elongation patterns, but also in determining the secondary cell wall composition.
PMID: 31521213
BMC Plant Biol , IF:3.497 , 2019 Nov , V19 (1) : P528 doi: 10.1186/s12870-019-2151-x
Auxin and cytokinin coordinate the dormancy and outgrowth of axillary bud in strawberry runner.
College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.; FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Zibo Agriculture and Rural Affairs Service Center, Zibo, 255400, China.; FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. gaozhen0695@163.com.; College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China. chenxu@fafu.edu.cn.; FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. chenxu@fafu.edu.cn.
BACKGROUND: Axillary buds allow the production of either vegetative or reproductive shoots, which display a plastic developmental potential of the plant to suit the prevailing environmental changes. Strawberry represents one of many plant species which displays horizontal above-ground growth of shoot development for asexual reproduction. Two distinct runner growth patterns exist in different strawberry species: one is called sympodial type such as Fragaria vesca, and the other one is called monopodial type such as Fragaria pentaphylla. Despite the runner growth morphology of these strawberry species have been well known, the mechanisms that determine the distinct patterns have rarely been reported. RESULTS: In this study, we used Fragaria vesca Hawaii-4 and Fragaria pentaphylla as model species, and captured the initiated dormant bud and non-dormant bud as materials to compare their transcriptome profiles and phytohormone content. Comparisons revealed that relatively higher auxin activity is present in the dormant bud and relatively higher cytokinin activity is in the non-dormant bud. Decapitation and pharmacological experiments on dormant buds showed that the reduction of auxin accumulation triggers the regeneration of vegetative shoots in dormant buds, and exogenous cytokinin application triggers cell fate turnover and generation of reproductive shoots. CONCLUSION: Here, we uncover a mechanism by which auxin and cytokinin coordinate the dormancy and outgrowth of axillary bud in strawberry runner. Our results suggest a contrasting behavior of auxin and cytokinin in control of axillary bud development, facilitating a preliminary understanding of shoot architecture formation in strawberry.
PMID: 31783789
BMC Plant Biol , IF:3.497 , 2019 Nov , V19 (1) : P523 doi: 10.1186/s12870-019-2144-9
The grapevine homeobox gene VvHB58 influences seed and fruit development through multiple hormonal signaling pathways.
State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China.; College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China.; Department of Horticulture, Michigan State University, East Lansing, MI, USA.; State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China. wangxiping@nwsuaf.edu.cn.; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China. wangxiping@nwsuaf.edu.cn.
BACKGROUND: The homeobox transcription factor has a diversity of functions during plant growth and development process. Previous transcriptome analyses of seed development in grape hybrids suggested that specific homeodomain transcription factors are involved in seed development in seedless cultivars. However, the molecular mechanism of homeobox gene regulating seed development in grape is rarely reported. RESULTS: Here, we report that the grapevine VvHB58 gene, encoding a homeodomain-leucine zipper (HD-Zip I) transcription factor, participates in regulating fruit size and seed number. The VvHB58 gene was differentially expressed during seed development between seedless and seeded cultivars. Subcellular localization assays revealed that the VvHB58 protein was located in the nucleus. Transgenic expression of VvHB58 in tomato led to loss of apical dominance, a reduction in fruit pericarp expansion, reduced fruit size and seed number, and larger endosperm cells. Analysis of the cytosine methylation levels within the VvHB58 promoter indicated that the differential expression during seed development between seedless and seeded grapes may be caused by different transcriptional regulatory mechanisms rather than promoter DNA methylation. Measurements of five classic endogenous hormones and expression analysis of hormone-related genes between VvHB58 transgenic and nontransgenic control plants showed that expression of VvHB58 resulted in significant changes in auxin, gibberellin and ethylene signaling pathways. Additionally, several DNA methylation-related genes were expressed differentially during seed development stages in seedless and seeded grapes, suggesting changes in methylation levels during seed development may be associated with seed abortion. CONCLUSION: VvHB58 has a potential function in regulating fruit and seed development by impacting multiple hormonal pathways. These results expand understanding of homeodomain transcription factors and potential regulatory mechanism of seed development in grapevine, and provided insights into molecular breeding for grapes.
PMID: 31775649
BMC Plant Biol , IF:3.497 , 2019 Nov , V19 (1) : P512 doi: 10.1186/s12870-019-2130-2
Auxin protects Arabidopsis thaliana cell suspension cultures from programmed cell death induced by the cellulose biosynthesis inhibitors thaxtomin A and isoxaben.
Centre SEVE, Departement de biologie, Universite de Sherbrooke, Sherbrooke, Quebec, J1K 2R1, Canada.; Present address: Groupe de Recherche en Biologie vegetale, Departement de chimie, biochimie et physique, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, Quebec, G9A 5H7, Canada.; Institut de Pharmacologie de Sherbrooke, Departement de pharmacologie et physiologie, Universite de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada.; Centre SEVE, Departement de biologie, Universite de Sherbrooke, Sherbrooke, Quebec, J1K 2R1, Canada. nathalie.beaudoin@usherbrooke.ca.
BACKGROUND: Thaxtomin A (TA) is a natural cellulose biosynthesis inhibitor (CBI) synthesized by the potato common scab-causing pathogen Streptomyces scabies. Inhibition of cellulose synthesis by TA compromises cell wall organization and integrity, leading to the induction of an atypical program of cell death (PCD). These processes may facilitate S. scabies entry into plant tissues. To study the mechanisms that regulate the induction of cell death in response to inhibition of cellulose synthesis, we used Arabidopsis thaliana cell suspension cultures treated with two structurally different CBIs, TA and the herbicide isoxaben (IXB). RESULTS: The induction of cell death by TA and IXB was abrogated following pretreatment with the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) and the natural auxin indole-3-acetic acid (IAA). The addition of auxin efflux inhibitors also inhibited the CBI-mediated induction of PCD. This effect may be due to intracellular accumulation of auxin. Auxin has a wide range of effects in plant cells, including a role in the control of cell wall composition and rigidity to facilitate cell elongation. Using Atomic Force Microscopy (AFM)-based force spectroscopy, we found that inhibition of cellulose synthesis by TA and IXB in suspension-cultured cells decreased cell wall stiffness to a level slightly different than that caused by auxin. However, the cell wall stiffness in cells pretreated with auxin prior to CBI treatment was equivalent to that of cells treated with auxin only. CONCLUSIONS: Addition of auxin to Arabidopsis cell suspension cultures prevented the TA- and IXB-mediated induction of cell death. Cell survival was also stimulated by inhibition of polar auxin transport during CBI-treatment. Inhibition of cellulose synthesis perturbed cell wall mechanical properties of Arabidopsis cells. Auxin treatment alone or with CBI also decreased cell wall stiffness, showing that the mechanical properties of the cell wall perturbed by CBIs were not restored by auxin. However, since auxin's effects on the cell wall stiffness apparently overrode those induced by CBIs, we suggest that auxin may limit the impact of CBIs by restoring its own transport and/or by stabilizing the plasma membrane - cell wall - cytoskeleton continuum.
PMID: 31752698
BMC Plant Biol , IF:3.497 , 2019 Nov , V19 (1) : P500 doi: 10.1186/s12870-019-2094-2
Identification of Bna.IAA7.C05 as allelic gene for dwarf mutant generated from tissue culture in oilseed rape.
Oil Crops Research Institute of Chinese Academy of Agricultural Sciences/Key Laboratory for Biological Sciences and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China.; Crop Research Institute, Gansu academy of Agricultural Sciences, Lanzhou, 730070, Gansu, China.; John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.; Crop Research Institute, Gansu academy of Agricultural Sciences, Lanzhou, 730070, Gansu, China. dongyungs@163.com.; Oil Crops Research Institute of Chinese Academy of Agricultural Sciences/Key Laboratory for Biological Sciences and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China. huqiong01@caas.cn.
BACKGROUND: Plant height is one of the most important agronomic traits in many crops due to its influence on lodging resistance and yield performance. Although progress has been made in the use of dwarfing genes in crop improvement, identification of new dwarf germplasm is still of significant interest for breeding varieties with increased yield. RESULTS: Here we describe a dominant, dwarf mutant G7 of Brassica napus with down-curved leaves derived from tissue culture. To explore the genetic variation responsible for the dwarf phenotype, the mutant was crossed to a conventional line to develop a segregating F2 population. Bulks were formed from plants with either dwarf or conventional plant height and subjected to high throughput sequencing analysis via mutation mapping (MutMap). The dwarf mutation was mapped to a 0.6 Mb interval of B. napus chromosome C05. Candidate gene analysis revealed that one SNP causing an amino acid change in the domain II of Bna.IAA7.C05 may contribute to the dwarf phenotype. This is consistent with the phenotype of a gain-of-function indole-3-acetic acid (iaa) mutant in Bna.IAA7.C05 reported recently. GO and KEGG analysis of RNA-seq data revealed the down-regulation of auxin related genes, including many other IAA and small up regulated response (SAUR) genes, in the dwarf mutant. CONCLUSION: Our studies characterize a new allele of Bna.IAA7.C05 responsible for the dwarf mutant generated from tissue culture. This may provide a valuable genetic resource for breeding for lodging resistance and compact plant stature in B. napus.
PMID: 31729952
Planta , IF:3.39 , 2019 Nov , V251 (1) : P13 doi: 10.1007/s00425-019-03310-3
Transgenic expression of Hyp-1 gene from Hypericum perforatum L. alters expression of defense-related genes and modulates recalcitrance to Agrobacterium tumefaciens.
Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, 4710-057, Braga, Portugal.; Centro de Quimica de Vila Real (CQ-VR), UTAD, 5000-801, Vila Real, Portugal.; National Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.; Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, 4710-057, Braga, Portugal.; Departamento de Biotecnologia Microbiana y de Plantas, Centro de Investigaciones Biologicas, CSIC, 28040, Madrid, Spain.; Departamento de Biotecnologia Microbiana y de Plantas, Centro de Investigaciones Biologicas, CSIC, 28040, Madrid, Spain. tenllado@cib.csic.es.; Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, 4710-057, Braga, Portugal. acpdias@bio.uminho.pt.; Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, 4710-057, Braga, Portugal. acpdias@bio.uminho.pt.; Center of Biological Engineering (CEB), University of Minho, 4710-057, Braga, Portugal. acpdias@bio.uminho.pt.
MAIN CONCLUSION: Phenolic oxidative coupling protein (Hyp-1) isolated from Hypericum perforatum L. was characterized as a defense gene involved in H. perforatum recalcitrance to Agrobacterium tumefaciens-mediated transformation Hypericum perforatum L. is a reservoir of high-value secondary metabolites of increasing interest to researchers and to the pharmaceutical industry. However, improving their production via genetic manipulation is a challenging task, as H. perforatum is recalcitrant to Agrobacterium tumefaciens-mediated transformation. Here, phenolic oxidative coupling protein (Hyp-1), a pathogenesis-related (PR) class 10 family gene, was selected from a subtractive cDNA library from A. tumefaciens-treated H. perforatum suspension cells. The role of Hyp-1 in defense against A. tumefaciens was analyzed in transgenic Nicotiana tabacum and Lactuca sativa overexpressing Hyp-1, and in Catharanthus roseus silenced for its homologous Hyp-1 gene, CrIPR. Results showed that Agrobacterium-mediated expression efficiency greatly decreased in Hyp-1 transgenic plants. However, silencing of CrIPR induced CrPR-5 expression and decreased expression efficiency of Agrobacterium. The expression of core genes involved in several defense pathways was also analyzed in Hyp-1 transgenic tobacco plants. Overexpression of Hyp-1 led to an ample down-regulation of key genes involved in auxin signaling, microRNA-based gene silencing, detoxification of reactive oxygen species, phenylpropanoid pathway and PRs. Moreover, Hyp-1 was detected in the nucleus, plasma membrane and the cytoplasm of epidermal cells by confocal microscopy. Overall, our findings suggest Hyp-1 modulates recalcitrance to A. tumefaciens-mediated transformation in H. perforatum.
PMID: 31776675
Planta , IF:3.39 , 2019 Nov , V250 (5) : P1475-1489 doi: 10.1007/s00425-019-03236-w
Nitric oxide and phytohormone interactions in the response of Lactuca sativa to salinity stress.
Instituto Federal Fluminense/Campus Avancado Sao Joao da Barra, Sao Joao da Barra, RJ, 28200-00, Brazil.; Departamento de Biologia Geral, Universidade Federal de Vicosa, Vicosa, MG, 36570-000, Brazil. jalves@ufv.br.; Departamento de Biologia Geral, Universidade Federal de Vicosa, Vicosa, MG, 36570-000, Brazil.; Instituto Federal Goiano, Campus Rio Verde, Rio Verde, GO, 75.901-970, Brazil.
MAIN CONCLUSION: Nitric oxide increased lettuce's tolerance to salinity by restoring its hormonal balance, consequently reducing Na + accumulation and activating defense mechanisms that allowed the attenuation of ionic, oxidative, and osmotic stresses. Agricultural crops are continually threatened by soil salinity. The plant's ability to tolerate soil salinity can be increased by treatment with the signaling molecule nitric oxide (NO). Involvement of NO in plant metabolism and its interactions with phytohormones have not been fully described, so knowledge about the role of this radical in signaling pathways remains fragmented. In this work, Lactuca sativa (lettuce) plants were subjected to four treatments: (1) control (nutrient solution); (2) SNP [nutrient solution containing 70 muM sodium nitroprusside (SNP), an NO donor]; (3) NaCl (nutrient solution containing 80 mM NaCl); or (4) SNP + NaCl (nutrient solution containing SNP and NaCl). The plants were exposed to these conditions for 24 h, and then, the roots and leaves were collected and used to evaluate biochemical parameters (reactive oxygen species (ROS) production, cell membrane damage, cell death, antioxidant enzymes activities, and proline concentration), physiological parameters (pigments' concentration and gas-exchange measurements), and phytohormone content. To evaluate growth, tolerance index, and nutrient concentration, the plants were exposed to the treatments for 3 days. L sativa exposure to NaCl triggered ionic, osmotic, and oxidative stress, which resulted in hormone imbalance, cell death, and decreased growth. These deleterious changes were correlated with Na(+) content in the vegetative tissues. Adding NO decreased Na(+) accumulation and stabilized the mineral nutrient concentration, which maintained the photosynthetic rate and re-established growth. NO-signaling action also re-established the phytohormones balance and resulted in antioxidant system activation and osmotic regulation, with consequent increase in plants tolerance to the salt.
PMID: 31327043
Plant Mol Biol , IF:3.302 , 2019 Nov , V101 (4-5) : P499-506 doi: 10.1007/s11103-019-00922-x
A simple and sensitive SYBR Gold-based assay to quantify DNA-protein interactions.
Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD, 57007, USA.; Center for Molecular Medicine, University of Nevada, Reno, 1664 N Virginia St, Reno, NV, 89557, USA.; Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, 57007, USA.; Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD, 57007, USA. senthil.subramanian@sdstate.edu.; Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA. senthil.subramanian@sdstate.edu.
A simple, accessible, and inexpensive assay to quantify the strength of DNA-protein interactions was developed. The assay relies on capturing DNA-protein complexes using an affinity resin that binds tagged, recombinant proteins. Sequential washes with filtration spin cups and centrifugation remove non-specific interactions in a gentle, uniform manner and a final elution isolates specific DNA-protein complexes. SYBR Gold nucleic acid stain is added to the eluted product and the fluorescence intensity accurately quantifies the amount of captured DNA, ultimately illustrating the relative strength of the DNA-protein interaction. The major utility of the assay resides in the versatility and quantitative nature of the SYBR Gold:nucleic acid interaction, eliminating the need for customized or labeled oligos and permitting relatively inexpensive quantification of binding capacity. The assay also employs DNA-protein complex capture by the very common purification tag, 6xHis, but other tags could likely be utilized. Further, SYBR Gold fluorescence is compatible with a wide variety of instruments, including UV transilluminators, a staple to any molecular biology laboratory. This assay was used to compare the binding capacities of different auxin response factor (ARF) transcription factors to various dsDNA targets, including the classical AuxRE motif and several divergent sequences. Results from dose-response assays suggest that different ARF proteins might show distinct comparative affinities for AuxRE variants, emphasizing that specific ARF-AuxRE binding strengths likely contribute to the complex and fine-tuned cellular auxin response.
PMID: 31621004
Plant Mol Biol , IF:3.302 , 2019 Nov , V101 (4-5) : P487-498 doi: 10.1007/s11103-019-00918-7
Identification of root transcriptional responses to shoot illumination in Arabidopsis thaliana.
PPGBM - Programa de Pos-Graduacao em Genetica e Biologia Molecular, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil.; PPGBOT - Programa de Pos-Graduacao em Botanica, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil.; PPGBCM - Programa de Pos-Graduacao em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil.; Instituto de Fisica and Instituto Nacional de Ciencia e Tecnologia: Sistemas Complexos, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.; Programa de Pos Graduacao em Bioinformatica, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.; Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, Leiden, The Netherlands.; PPGBM - Programa de Pos-Graduacao em Genetica e Biologia Molecular, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil. felipe.maraschin@ufrgs.br.; PPGBOT - Programa de Pos-Graduacao em Botanica, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil. felipe.maraschin@ufrgs.br.; Departamento de Botanica, Universidade Federal do Rio Grande do Sul - UFRGS, Av. Bento Goncalves 9500, Predio 43.423, sala 216, Porto Alegre, RS, CEP 91501-970, Brazil. felipe.maraschin@ufrgs.br.
KEY MESSAGE: The transcriptional profile of roots is highly affected by shoot illumination. Transcriptogram analysis allows the identification of cellular processes that are not detected by DESeq. Light is a key environmental factor regulating plant growth and development. Arabidopsis thaliana seedlings grown under light display a photomorphogenic development pattern, showing short hypocotyl and long roots. On the other hand, when grown in darkness, they display skotomorphogenic development, with long hypocotyls and short roots. Although many signals from shoots might be important for triggering root growth, the early transcriptional responses that stimulate primary root elongation are still unknown. Here, we aimed to investigate which genes are involved in the early photomorphogenic root development of dark grown roots. We found that 1616 genes 4 days after germination (days-old), and 3920 genes 7 days-old were differently expressed in roots when the shoot was exposed to light. Of these genes, 979 were up regulated in 4 days and 2784 at 7 days-old. We compared the functional categorization of differentially regulated processes by two methods: GO term enrichment and transcriptogram analysis. Expression analysis of nine selected candidate genes in roots confirmed the data observed in the RNA-seq analysis. Loss-of-function mutants of these selected differentially expressed genes suggest the involvement of these genes in root development in response to shoot illumination. Our findings are consistent with the observation that dark grown roots respond to the shoot-perceived aboveground light environment.
PMID: 31560104
DNA Cell Biol , IF:3.191 , 2019 Nov , V38 (11) : P1292-1302 doi: 10.1089/dna.2019.4896
Identification and Analysis of Genes Involved in Auxin, Abscisic Acid, Gibberellin, and Brassinosteroid Metabolisms Under Drought Stress in Tender Shoots of Tea Plants.
Tea Science Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, China.; College of Agriculture, Nanjing Agricultural University, Nanjing, China.
Endogenous phytohormones auxin (indole-3-acetic acid [IAA]), abscisic acid (ABA), gibberellin (GA3), and brassinosteroid (BR) play a role in responses to drought stress in higher plants. Tea plant is one of the major economic corps worldwide. The tender shoots of tea plants are the main source for tea production. The effects of drought stress on endogenous IAA, ABA, GA3, and BR metabolisms in tender shoots of tea plants need to be illustrated. In this study, a total of 17 IAA-related genes, 17 ABA-related genes, 18 GA3-related genes, and 8 BR-related genes were identified under drought stress in tender shoots of tea plants, respectively. By using a combination of phytohormone determination, phylogenetic tree construction and sequence analysis, gene expression profiles, functional classification, Kyoto encyclopedia of genes and genomes enrichment, and distribution of genes analysis, we have demonstrated that IAA, ABA, GA3, and BR metabolisms might participate in the regulation of the response to drought stress in tender shoots of tea plants. The expression level of CsLYCE negatively correlated with ABA accumulation under drought stress. Our findings could shed new light on the effects of drought stress on the IAA, ABA, GA3, and BR metabolisms in tender shoots of tea plants.
PMID: 31560570
Saudi J Biol Sci , IF:2.802 , 2019 Nov , V26 (7) : P1400-1410 doi: 10.1016/j.sjbs.2018.05.024
Phosphate solubilizing rhizobacteria as alternative of chemical fertilizer for growth and yield of Triticum aestivum (Var. Galaxy 2013).
Department of Microbiology and Molecular Genetics, The Women University Multan, 66000, Pakistan.
Aim: The presence of Phosphorus as a macronutrient in soil is necessary for plant growth and its deficiency restricts crop yield. Therefore, the aim of current study is to isolate promising rhizospheric phosphate solubilizing bacteria presenting with plant growth promoting (PGP) traits and their utilization as biofertilizers to improve Triticum aestivum (Var. Galaxy 2013) growth and nutrition. Method: Out of 30 isolates obtained from rhizosphere of various plants of different regions, 10 best PSRB strains (WumS-3, WumS-4, WumS-5, WumS-11, WumS-12, WumS-21, WumS-24, WumS-25, WumS-26 and WumS-28) were selected based on their high P solubilization and good PGP (auxin, psiderphore, HCN, Nitrogen fixation) activities. Triticum aestivum (Var. Galaxy 2013) was used as an experimental crop under laboratory and field conditions. Results: In this study, P solubilization capacity of selected strains were found 4-7 solubilization index on agar plate and 30-246microg/ml in liquid broth respectively. The optimum conditions for phosphate solubilization under in vitro condition were found 35 degrees C at pH 7, glucose as good carbon source and ammonium nitrate as a good nitrogen source. Furthermore, the selected strains had the ability to produces phytohormones (indole acetic acid), siderophore, ammonia and Hydrogen Cyanide. Finally, PSRB inoculum showed significant (p<0.05) increase (50%-80%) in seed germination while 10-90% increase in root length and shoot length was found as compared to control in laboratory condition. Under natural conditions, 40-80% increase in seed germination while 5-34.8% increase in shoot length and 5-96% increase in seed weight was also observed. Conclusion: Isolated strains are promising PSRB that enhance plant growth and this research is a base for recommending the use of these bacterial strains for biofertilizer, as an alternative of chemical fertilizer, for Triticum aestivum L. production.
PMID: 31762601
Plants (Basel) , IF:2.762 , 2019 Nov , V8 (11) doi: 10.3390/plants8110473
Identification and Expression Analysis of Gretchen Hagen 3 (GH3) in Kiwifruit (Actinidia chinensis) During Postharvest Process.
Jiangxi Key Laboratory for Postharvest Technology and Nondestructive Testing of Fruits & Vegetables, Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables, Jiangxi Agricultural University, Nanchang 330045, China.; College of Agronomy, Jiangxi Agricultural University, Nanchang 330045, China.; Pingxiang University, Pingxiang 337055, China.
In plants, the Gretchen GH3 (GH3) protein is involved in free auxin (IAA) and amino acid conjugation, thus controlling auxin homeostasis. To date, many GH3 gene families have been identified from different plant species. However, the GH3 gene family in kiwifruit (Actinidia chinensis) has not been reported. In this study, 12 AcGH3 genes were identified, phylogenetic analysis of AtGH3 (Arabidopsis), SlGH3 (Solanum lycopersicum), and AcGH3 provided insights into various orthologous relationships among these proteins, which were categorized into three groups. Expression analysis of AcGH3 genes at different postharvest stages suggested limited or no role for most of the AcGH3 genes at the initiation of fruit ripening. AcGH3.1 was the only gene exhibiting ripening-associated expression. Further study showed that the expression of AcGH3.1 gene was induced by NAA (1-naphthylacetic acid, auxin analogue) and inhibited by 1-MCP (1-methylcyclopropene, ethylene receptor inhibitor), respectively. AcGH3.1 gene silencing inhibited gene expression and delayed fruit softening in kiwifruit. The results indicate that AcGH3.1 may play an important role in the softening process of fruits. Analysis of the AcGH3.1 promoter revealed the presence of many cis-elements related to hormones, light, and drought. The determination of GUS (beta-Galactosidase) enzyme activity revealed that promoter activity increased strikingly upon abscisic acid (ABA), ethylene, or NAA treatment, and significantly decreased with salicylic acid (SA) treatment. The present study could help in the identification of GH3 genes and revelation of AcGH3.1 gene function during postharvest stages, which pave the way for further functional verification of the AcGH3.1 gene.
PMID: 31698719
Protoplasma , IF:2.751 , 2019 Nov , V256 (6) : P1657-1666 doi: 10.1007/s00709-019-01409-8
Determinate root development in the halted primary root1 mutant of Arabidopsis correlates with death of root initial cells and an enhanced auxin response.
Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio A1', Ciudad Universitaria, C. P., 58030, Morelia, Michoacan, Mexico.; Facultad de Quimico Farmacobiologia, Universidad Michoacana de San Nicolas de Hidalgo, Tzintzuntzan 173, Matamoros, C. P., 58240, Morelia, Michoacan, Mexico.; Catedratico CONACYT-Instituto de Ecologia, A.C., Red de Estudios Moleculares Avanzados, Edificio B, Campus III, Carretera Antigua a Coatepec 351, El Haya, C. P., 91070, Xalapa, Veracruz, Mexico.; Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio A1', Ciudad Universitaria, C. P., 58030, Morelia, Michoacan, Mexico. jbucio@umich.mx.
The transit from indeterminate to determinate root developmental program compromises growth and causes the differentiation of the meristem, but a direct link between this process with auxin signaling and/or viability of initial cells remains untested. Here, through the isolation and characterization of the halted primary root1 (hpr1) mutant of Arabidopsis, which develops primary and lateral roots with genetically stable determinate growth after germination, we show that the differentiation of the root meristem correlates with enhanced auxin responsiveness and is preceded by the death of provasculature initial cells in both primary and lateral roots. Supplementation of indole-3-acetic acid causes both a dose-dependent repression of primary root growth and an induction of DR5:uidA expression in wild-type seedlings, and these effects were exacerbated in hpr1 mutants. The damage of provasculature initial cells in the root of hpr1 mutants occurred at earlier times than the full differentiation of the meristem, and correlates with a reduced expression domain of CycB1:uidA and PRZ:uidA. Thus, HPR1 plays critical functions for stem cell maintenance, auxin homeostasis, cell division in the meristem, and indeterminate root growth.
PMID: 31273542
Protoplasma , IF:2.751 , 2019 Nov , V256 (6) : P1507-1517 doi: 10.1007/s00709-019-01396-w
Elevated gibberellin altered morphology, anatomical structure, and transcriptional regulatory networks of hormones in celery leaves.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. xiongaisheng@njau.edu.cn.
Gibberellins (GAs), as one of the important hormones in regulating the growth and development of higher plants, can significantly promote cell elongation and expansion. Celery is a widely grown leafy vegetable crop with rich nutritional value. However, the effect of gibberellins on celery leaves is unclear. In this paper, the celery variety "Jinnan Shiqin" plants were treated with gibberellic acid (GA3) and paclobutrazol (PBZ, a gibberellin inhibitor). Our results showed that GA3 treatment promoted the growth of celery leaves and caused lignification of celery leaf tissue. In addition, the transcript levels of genes associated with gibberellins, auxin, cytokinins, ethylene, jasmonic acid, abscisic acid, and brassinolide were altered in response to increased or decreased exogenous gibberellins or inhibitor. GA3 may regulate celery growth by interacting with other hormones through crosstalk mechanisms. This study provided a reference for further study of the regulation mechanism of gibberellins metabolism, and exerted effects on understanding the role of gibberellins in the growth and development of celery.
PMID: 31168667
3 Biotech , IF:1.798 , 2019 Nov , V9 (11) : P434 doi: 10.1007/s13205-019-1960-9
Deciphering the transcriptomic insight during organogenesis in Castor (Ricinus communis L.), Jatropha (Jatropha curcas L.) and Sunflower (Helianthus annuus L.).
1Andhra University, Visakhapatnam, 530 003 India.0000 0001 0728 2694grid.411381.e; 2ICAR-Indian Institute of Oilseeds Research (Formerly DOR), Rajendranagar, Hyderabad, 500 007 India.grid.464816.9; 3Osmania University, Tarnaka, Hyderabad, 500 007 India.0000 0001 1456 3750grid.412419.b; AgriGenome Labs Pvt. Ltd, BTIC, MN iHub, Genome Valley, Hyderabad, Telangana State 500 078 India.; AgriGenome Labs Pvt. Ltd, SmartCity Kochi, Infopark Road, Kakkanad, 682 042 India.
Cultivation of the castor crop is hindered by various factors and one of the approaches for genetic improvement of the crop is through exploitation of biotechnological tools. Response of castor tissues to in vitro culture is poor which necessitated this study on understanding the molecular basis of organogenesis in cultured tissues of castor, through de novo transcriptome analysis and by comparing with jatropha and sunflower having good regeneration ability. Transcriptome profiling analysis was carried out with hypocotyl explants from castor, jatropha and cotyledons from sunflower cultured on MS media supplemented with different concentrations of hormones. Differentially expressed genes during dedifferentiation and organogenic differentiation stages of callus included components of auxin and cytokinin signaling, secondary metabolite synthesis, genes encoding transcription factors, receptor kinases and protein kinases. In castor, many genes involved in auxin biosynthesis and homeostasis like WAT1, vacuolar transporter genes, transcription factors like short root like protein were down-regulated while genes like DELLA were up-regulated accounting for regeneration recalcitrance. Validation of 62 DEGs through qRT-PCR showed a consensus of 77.4% of the genes expressed. Overall study provides set of genes involved in the process of organogenesis in three oilseed crops which forms a basis for understanding and improving the efficiency of plant regeneration and genetic transformation in castor.
PMID: 31696039
Genes Genomics , IF:1.188 , 2019 Nov , V41 (11) : P1241-1251 doi: 10.1007/s13258-019-00852-4
Validation of MADS-box genes from apple fruit pedicels during early fruit abscission by transcriptome analysis and real-time PCR.
Apple Research Institute, National Institute of Horticultural and Herbal Science, Rural Development Administration, Gunwi, 39000, South Korea.; Department of Plant Science, Seoul National University, Seoul, 08826, South Korea.; Department of Plant Resources and Environment, Jeju National University, Jeju, 63243, South Korea. yschung@jejunu.ac.kr.
BACKGROUND: Fruit abscission in an isolated region called abscission zone (AZ) is regulated by several genes including JOINTLESS, MACROCALYX and SEPALLATA, MADS-box genes, in tomato. OBJECTIVE: The surviving central pedicels and the abscised lateral pedicels were examined in fruit clusters in order to investigate apple MADS-box genes from fruit pedicels of self-abscising apple 'Saika' during early fruit abscission. METHODS: After performing RNA-Seq, transcription profiling was conducted on the MADS-box genes from apple central and lateral pedicels. The JOINTLESS homolog of apple (MdJOINTLESS) was amplified using degenerate primers annealing to a highly conserved domain based on the orthologous genes of various crops, including JOINTLESS gene of tomato. The expression pattern of MdJOINTLESS was investigated in central and lateral pedicles by real-time PCR. RESULTS: Some homologs were found which similar to JOINTLESS, MACROCALYX and SEPALLATA of tomato MADS-box genes from transcriptome analysis and RACE. Using phylogenetic analyses with the MADS-box gene family, MdJOINTLESS was classified into the SHORT VEGETATIVE PHASE (SVP) clade that included Arabidopsis and other crops. The expression level of MdJOINTLESS in central pedicel was more than twice as high as that of lateral pedicel. CONCLUSION: In the current study, we could find apple homologs of JOINTLESS, MACROCALYX, SEPALLATA, which were known to regulate pedicel AZ development in tomato. Furthermore, MdJOINTLESS might contribute to auxin gradation, influencing hierarchical ranking of auxin transport between fruit pedicels of self-abscising apple.
PMID: 31350732
Proc Math Phys Eng Sci , 2019 Nov , V475 (2231) : P20190015 doi: 10.1098/rspa.2019.0015
Auxin transport model for leaf venation.
Mathematics, CEMSE, KAUST, Thuwal 23955-6900, KSA.; Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.; DAMTP, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK.; Faculty of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, Vienna 1090, Austria.
The plant hormone auxin controls many aspects of the development of plants. One striking dynamical feature is the self-organization of leaf venation patterns which is driven by high levels of auxin within vein cells. The auxin transport is mediated by specialized membrane-localized proteins. Many venation models have been based on polarly localized efflux-mediator proteins of the PIN family. Here, we investigate a modelling framework for auxin transport with a positive feedback between auxin fluxes and transport capacities that are not necessarily polar, i.e. directional across a cell wall. Our approach is derived from a discrete graph-based model for biological transportation networks, where cells are represented by graph nodes and intercellular membranes by edges. The edges are not a priori oriented and the direction of auxin flow is determined by its concentration gradient along the edge. We prove global existence of solutions to the model and the validity of Murray's Law for its steady states. Moreover, we demonstrate with numerical simulations that the model is able connect an auxin source-sink pair with a mid-vein and that it can also produce branching vein patterns. A significant innovative aspect of our approach is that it allows the passage to a formal macroscopic limit which can be extended to include network growth. We perform mathematical analysis of the macroscopic formulation, showing the global existence of weak solutions for an appropriate parameter range.
PMID: 31824212