植物生长素文献速览 2019-06-01

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Plant Cell , IF:9.618 , 2019 May , V31 (5) : P1155-1170 doi: 10.1105/tpc.18.00803

The Transcription Factors TCP4 and PIF3 Antagonistically Regulate Organ-Specific Light Induction of SAUR Genes to Modulate Cotyledon Opening during De-Etiolation in Arabidopsis.

Dong, Jie and Sun, Ning and Yang, Jing and Deng, Zhaoguo and Lan, Jingqiu and Qin, Genji and He, Hang and Deng, Xing Wang and Irish, Vivian F and Chen, Haodong and Wei, Ning

Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520.; State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Advanced Agricultural Sciences and School of Life Sciences, Peking University, Beijing 100871, China.; State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Advanced Agricultural Sciences and School of Life Sciences, Peking University, Beijing 100871, China ning.wei@yale.edu chenhaodong@pku.edu.cn.; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520 ning.wei@yale.edu chenhaodong@pku.edu.cn.

Light elicits different growth responses in different organs of plants. These organ-specific responses are prominently displayed during de-etiolation. While major light-responsive components and early signaling pathways in this process have been identified, this information has yet to explain how organ-specific light responses are achieved. Here, we report that members of the TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) transcription factor family participate in photomorphogenesis and facilitate light-induced cotyledon opening in Arabidopsis (Arabidopsis thaliana). Chromatin immunoprecipitation sequencing and RNA sequencing analyses indicated that TCP4 targets a number of SMALL AUXIN UPREGULATED RNA (SAUR) genes that have previously been shown to exhibit organ-specific, light-responsive expression. We demonstrate that TCP4-like transcription factors, which are predominantly expressed in the cotyledons of both light- and dark-grown seedlings, activate SAUR16 and SAUR50 expression in response to light. Light regulates the binding of TCP4 to the promoters of SAUR14, SAUR16, and SAUR50 through PHYTOCHROME-INTERACTING FACTORs (PIFs). PIF3, which accumulates in etiolated seedlings and its levels rapidly decline upon light exposure, also binds to the SAUR16 and SAUR50 promoters, while suppressing the binding of TCP4 to these promoters in the dark. Our study reveals that the interplay between light-responsive factors PIFs and the developmental regulator TCP4 determines the cotyledon-specific light regulation of SAUR16 and SAUR50, which contributes to cotyledon closure and opening before and after de-etiolation.

PMID: 30914467

Plant Cell , IF:9.618 , 2019 May , V31 (5) : P1043-1062 doi: 10.1105/tpc.18.00978

Tomato MYB21 Acts in Ovules to Mediate Jasmonate-Regulated Fertility.

Schubert, Ramona and Dobritzsch, Susanne and Gruber, Cornelia and Hause, Gerd and Athmer, Benedikt and Schreiber, Tom and Marillonnet, Sylvestre and Okabe, Yoshihiro and Ezura, Hiroshi and Acosta, Ivan F and Tarkowska, Danuse and Hause, Bettina

Department of Cell and Metabolic Biology, Institute of Plant Biochemistry, 06120 Halle, Germany.; Martin Luther University Halle Wittenberg, Biocenter, Electron Microscopy, 06120 Halle, Germany.; Tsukuba Plant Innovation Research Center, University of Tsukuba, Tsukuba, Japan.; Max Planck Institute for Plant Breeding Research, 50829 Koln, Germany.; Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany, Czech Academy of Sciences, v.v.i., CZ-78371, Olomouc, Czech Republic.; Department of Cell and Metabolic Biology, Institute of Plant Biochemistry, 06120 Halle, Germany Bettina.Hause@ipb-halle.de.

The function of the plant hormone jasmonic acid (JA) in the development of tomato (Solanum lycopersicum) flowers was analyzed with a mutant defective in JA perception (jasmonate-insensitive1-1, jai1-1). In contrast with Arabidopsis (Arabidopsis thaliana) JA-insensitive plants, which are male sterile, the tomato jai1-1 mutant is female sterile, with major defects in female development. To identify putative JA-dependent regulatory components, we performed transcriptomics on ovules from flowers at three developmental stages from wild type and jai1-1 mutants. One of the strongly downregulated genes in jai1-1 encodes the MYB transcription factor SlMYB21. Its Arabidopsis ortholog plays a crucial role in JA-regulated stamen development. SlMYB21 was shown here to exhibit transcription factor activity in yeast, to interact with SlJAZ9 in yeast and in planta, and to complement Arabidopsis myb21-5 To analyze SlMYB21 function, we generated clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR associated protein 9 (Cas9) mutants and identified a mutant by Targeting Induced Local Lesions in Genomes (TILLING). These mutants showed female sterility, corroborating a function of MYB21 in tomato ovule development. Transcriptomics analysis of wild type, jai1-1, and myb21-2 carpels revealed processes that might be controlled by SlMYB21. The data suggest positive regulation of JA biosynthesis by SlMYB21, but negative regulation of auxin and gibberellins. The results demonstrate that SlMYB21 mediates at least partially the action of JA and might control the flower-to-fruit transition..

PMID: 30894458

Curr Biol , IF:9.601 , 2019 May , V29 (10) : P1669-1676.e4 doi: 10.1016/j.cub.2019.03.042

Soil Salinity Limits Plant Shade Avoidance.

Hayes, Scott and Pantazopoulou, Chrysoula K and van Gelderen, Kasper and Reinen, Emilie and Tween, Adrian Louis and Sharma, Ashutosh and de Vries, Michel and Prat, Salome and Schuurink, Robert C and Testerink, Christa and Pierik, Ronald

Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Kruytgebouw, Padualaan 8, 3584CH, Utrecht, the Netherlands; Centro Nacional de Biotecnologia, CSIC, Calle Darwin 3, Madrid 28049, Spain.; Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Kruytgebouw, Padualaan 8, 3584CH, Utrecht, the Netherlands.; School of Biological Sciences, Life Sciences Building, University of Bristol, Bristol BS8 1TQ, UK.; Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, the Netherlands.; Centro Nacional de Biotecnologia, CSIC, Calle Darwin 3, Madrid 28049, Spain.; Laboratory of Plant Physiology, Wageningen University and Research, Radix Building, Wageningen 6700 AA, the Netherlands.; Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Kruytgebouw, Padualaan 8, 3584CH, Utrecht, the Netherlands. Electronic address: r.pierik@uu.nl.

Global food production is set to keep increasing despite a predicted decrease in total arable land [1]. To achieve higher production, denser planting will be required on increasingly degraded soils. When grown in dense stands, crops elongate and raise their leaves in an effort to reach sunlight, a process termed shade avoidance [2]. Shade is perceived by a reduction in the ratio of red (R) to far-red (FR) light and results in the stabilization of a class of transcription factors known as PHYTOCHROME INTERACTING FACTORS (PIFs) [3, 4]. PIFs activate the expression of auxin biosynthesis genes [4, 5] and enhance auxin sensitivity [6], which promotes cell-wall loosening and drives elongation growth. Despite our molecular understanding of shade-induced growth, little is known about how this developmental program is integrated with other environmental factors. Here, we demonstrate that low levels of NaCl in soil strongly impair the ability of plants to respond to shade. This block is dependent upon abscisic acid (ABA) signaling and the canonical ABA signaling pathway. Low R:FR light enhances brassinosteroid (BR) signaling through BRASSINOSTEROID SIGNALING KINASE 5 (BSK5) and leads to the activation of BRI1 EMS SUPPRESSOR 1 (BES1). ABA inhibits BSK5 upregulation and interferes with GSK3-like kinase inactivation by the BR pathway, thus leading to a suppression of BES1:PIF function. By demonstrating a link between light, ABA-, and BR-signaling pathways, this study provides an important step forward in our understanding of how multiple environmental cues are integrated into plant development.

PMID: 31056387

Proc Natl Acad Sci U S A , IF:9.412 , 2019 May , V116 (21) : P10563-10567 doi: 10.1073/pnas.1821445116

beta-Cyclocitral is a conserved root growth regulator.

Dickinson, Alexandra J and Lehner, Kevin and Mi, Jianing and Jia, Kun-Peng and Mijar, Medhavinee and Dinneny, Jose and Al-Babili, Salim and Benfey, Philip N

Department of Biology, Duke University, Durham, NC 27708.; Howard Hughes Medical Institute, Duke University, Durham, NC 27708.; Department of Plant Biology, Carnegie Institute of Science, Stanford, CA 94305.; Biological and Environmental Sciences and Engineering Division, The Bioactives Lab, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Saudi Arabia.; Department of Biology, Stanford University, Palo Alto, CA 94305.; Department of Biology, Duke University, Durham, NC 27708; philip.benfey@duke.edu.

Natural compounds capable of increasing root depth and branching are desirable tools for enhancing stress tolerance in crops. We devised a sensitized screen to identify natural metabolites capable of regulating root traits in Arabidopsis beta-Cyclocitral, an endogenous root compound, was found to promote cell divisions in root meristems and stimulate lateral root branching. beta-Cyclocitral rescued meristematic cell divisions in ccd1ccd4 biosynthesis mutants, and beta-cyclocitral-driven root growth was found to be independent of auxin, brassinosteroid, and reactive oxygen species signaling pathways. beta-Cyclocitral had a conserved effect on root growth in tomato and rice and generated significantly more compact crown root systems in rice. Moreover, beta-cyclocitral treatment enhanced plant vigor in rice plants exposed to salt-contaminated soil. These results indicate that beta-cyclocitral is a broadly effective root growth promoter in both monocots and eudicots and could be a valuable tool to enhance crop vigor under environmental stress.

PMID: 31068462

New Phytol , IF:8.512 , 2019 May , V222 (3) : P1230-1234 doi: 10.1111/nph.15626

On hormonal regulation of the dynamic apical hook development.

Wang, Yichuan and Guo, Hongwei

Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.

Contents Summary 1230 I. Introduction 1230 II. Apical hook development is a spatio-temporally dynamic process orchestrated by a complex signaling network 1231 III. Central players of apical hook development: auxin and HOOKLESS1 1232 IV. Towards a cellular-based understanding of hormonal regulation of apical hook development with cutting-edge toolboxes 1232 V. Conclusions 1233 Acknowledgements 1233 References 1233 SUMMARY: To deal with the ever-changing environment, sessile plants adapt diverse and plastic organ structures during postembryonic development. Among these, the apical hook forms shortly after seed germination of most dicots, and protects the delicate shoot meristem from mechanical damage during soil emergence. For decades, this structure has been taken as an excellent model for the investigation of the mechanisms underlying the differential growth of plant tissues. Here, we summarize recent advances in the investigation of the hormonal regulation of apical hook development, focusing on the convergence to auxin and a central regulator HOOKLESS1 (HLS1). We propose the revisitation of hook curvature kinematics at suborgan and single-cell resolution, and further pursuance of the mechanistics of apical hook development through combinatorial approaches of automated imaging and multidimensional modeling.

PMID: 30537131

Plant Physiol , IF:6.902 , 2019 May , V180 (1) : P453-464 doi: 10.1104/pp.19.00127

An Essential Role for miRNA167 in Maternal Control of Embryonic and Seed Development.

Yao, Xiaozhen and Chen, Jilin and Zhou, Jie and Yu, Hanchuanzhi and Ge, Chennan and Zhang, Min and Gao, Xiuhua and Dai, Xinhua and Yang, Zhong-Nan and Zhao, Yunde

Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China.; Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093-0116.; Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093-0116 yundezhao@ucsd.edu.

Maternal cells play a critical role in ensuring the normal development of embryos, endosperms, and seeds. Mutations that disrupt the maternal control of embryogenesis and seed development are difficult to identify. Here, we completely deleted four MICRORNA167 (MIR167) genes in Arabidopsis (Arabidopsis thaliana) using a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein9 (Cas9) genome-editing technology. We found that plants with a deletion of MIR167A phenocopied plants overexpressing miRNA167-resistant versions of Auxin Response Factor6 (ARF6) or ARF8, two miRNA167 targets. Both the mir167a mutant and the ARF overexpression lines were defective in anther dehiscence and ovule development. Serendipitously, we found that the mir167a (female symbol) x wild type (male symbol) crosses failed to produce normal embryos and endosperms, despite the findings that embryos with either mir167a(+/-) or mir167a(-/-) genotypes developed normally when mir167a(+/-) plants were self-pollinated, revealing a central role of MIR167A in maternal control of seed development. The mir167a phenotype is 100% penetrant, providing a great genetic tool for studying the roles of miRNAs and auxin in maternal control. Moreover, we found that mir167a mutants flowered significantly later than wild-type plants, a phenotype that was not observed in the ARF overexpression lines. We show that the reproductive defects of mir167a mutants were suppressed by a decrease of activities of ARF6, ARF8, or both. Our results clearly demonstrate that MIR167A is the predominant MIR167 member in regulating Arabidopsis reproduction and that MIR167A acts as a maternal gene that functions largely through ARF6 and ARF8.

PMID: 30867333

Plant Physiol , IF:6.902 , 2019 May , V180 (1) : P289-304 doi: 10.1104/pp.18.01225

The AAA-ATPase MIDASIN 1 Functions in Ribosome Biogenesis and Is Essential for Embryo and Root Development.

Li, Peng-Cheng and Li, Ke and Wang, Juan and Zhao, Chuan-Zhi and Zhao, Shu-Zhen and Hou, Lei and Xia, Han and Ma, Chang-Le and Wang, Xing-Jun

Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan 250100, PR China.; College of Life Science, Shandong University, Qingdao 266237, PR China.; College of Life Sciences, Shandong Normal University, Jinan 250014, PR China.; Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan 250100, PR China xingjunw@hotmail.com.

Ribosome biogenesis is an orchestrated process that relies on many assembly factors. The AAA-ATPase Midasin 1 (Mdn1) functions as a ribosome assembly factor in yeast (Saccharomyces cerevisiae), but the roles of MDN1 in Arabidopsis (Arabidopsis thaliana) are poorly understood. Here, we showed that the Arabidopsis null mutant of MDN1 is embryo-lethal. Using the weak mutant mdn1-1, which maintains viability, we found that MDN1 is critical for the regular pattern of auxin maxima in the globular embryo and functions in root meristem maintenance. By detecting the subcellular distribution of ribosome proteins, we noted that mdn1-1 impairs nuclear export of the pre-60S ribosomal particle. The processing of ribosomal precusor RNAs, including 35S, 27SB, and 20S, is also affected in this mutant. MDN1 physically interacts with PESCADILLO2 (PES2), an essential assembly factor of the 60S ribosome, and the observed mislocalization of PES2 in mdn1-1 further implied that MDN1 plays an indispensable role in 60S ribosome biogenesis. Therefore, the observed hypersensitivity of mdn1-1 to a eukaryotic translation inhibitor and high-sugar conditions might be associated with the defect in ribosome biogenesis. Overall, this work establishes a role of Arabidopsis MDN1 in ribosome biogenesis, which agrees with its roles in embryogenesis and root development.

PMID: 30755475

Plant Physiol , IF:6.902 , 2019 May , V180 (1) : P480-496 doi: 10.1104/pp.18.01393

Identification of Novel Inhibitors of Auxin-Induced Ca(2+) Signaling via a Plant-Based Chemical Screen.

De Vriese, Kjell and Himschoot, Ellie and Dunser, Kai and Nguyen, Long and Drozdzecki, Andrzej and Costa, Alex and Nowack, Moritz K and Kleine-Vehn, Jurgen and Audenaert, Dominique and Beeckman, Tom and Vanneste, Steffen

Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.; VIB Center for Plant Systems Biology, 9052 Gent, Belgium.; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria.; Screening Core, VIB, 9052 Gent, Belgium.; Centre for Bioassay Development and Screening (C-BIOS), Ghent University, 9052 Ghent, Belgium.; Department of Biosciences, University of Milan, 20133 Milan, Italy.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium stnes@psb.vib-ugent.be.; Lab of Plant Growth Analysis, Ghent University Global Campus, 21985 Incheon, Republic of Korea.

Many signal perception mechanisms are connected to Ca(2+)-based second messenger signaling to modulate specific cellular responses. The well-characterized plant hormone auxin elicits a very rapid Ca(2+) signal. However, the cellular targets of auxin-induced Ca(2+) are largely unknown. Here, we screened a biologically annotated chemical library for inhibitors of auxin-induced Ca(2+) entry in plant cell suspensions to better understand the molecular mechanism of auxin-induced Ca(2+) and to explore the physiological relevance of Ca(2+) in auxin signal transduction. Using this approach, we defined a set of diverse, small molecules that interfere with auxin-induced Ca(2+) entry. Based on annotated biological activities of the hit molecules, we found that auxin-induced Ca(2+) signaling is, among others, highly sensitive to disruption of membrane proton gradients and the mammalian Ca(2+) channel inhibitor bepridil. Whereas protonophores nonselectively inhibited auxin-induced and osmotic stress-induced Ca(2+) signals, bepridil specifically inhibited auxin-induced Ca(2+) We found evidence that bepridil severely alters vacuolar morphology and antagonized auxin-induced vacuolar remodeling. Further exploration of this plant-tailored collection of inhibitors will lead to a better understanding of auxin-induced Ca(2+) entry and its relevance for auxin responses.

PMID: 30737267

Plant Cell Environ , IF:6.362 , 2019 May , V42 (5) : P1615-1629 doi: 10.1111/pce.13510

DWARF4 accumulation in root tips is enhanced via blue light perception by cryptochromes.

Sakaguchi, Jun and Matsushita, Tomonao and Watanabe, Yuichiro

Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan.; Faculty of Agriculture, Kyushu University, Fukuoka, 819-0395, Japan.

Brassinosteroid (BR) signalling is known to be coordinated with light signalling in above ground tissue. Many studies focusing on the shade avoidance response in above ground tissue or hypocotyl elongation in darkness have revealed the contribution of the BR signalling pathway to these processes. We previously analysed the expression of DWARF 4 (DWF4), a key BR biosynthesis enzyme, and revealed that light perception in above ground tissues triggered DWF4 accumulation in root tips. To determine the required wavelength of light and photoreceptors responsible for this regulation, we studied DWF4-GUS marker plants grown in several monochromatic light conditions. We revealed that monochromatic blue LED light could induce DWF4 accumulation in primary root tips and root growth as much as white light, whereas monochromatic red LED could not. Consistent with this, a cryptochrome1/2 double mutant showed retarded root growth under white light whereas a phytochromeA/B double mutant did not. Taken together, our data strongly indicated that blue light signalling was important for DWF4 accumulation in root tips and root growth. Furthermore, DWF4 accumulation patterns in primary root tips were not altered by auxin or sugar treatment. Therefore, we hypothesize that blue light signalling from the shoot tissue is different from auxin and sugar signalling.

PMID: 30620085

Plant Cell Environ , IF:6.362 , 2019 May , V42 (5) : P1715-1728 doi: 10.1111/pce.13513

Plant hormone effects on isoprene emission from tropical tree in Ficus septica.

Parveen, Shahanaz and Iqbal, Md Asif and Mutanda, Ishmael and Rashid, Md Harun-Ur- and Inafuku, Masashi and Oku, Hirosuke

The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan.; Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan.; Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.; Graduate School of Agriculture, University of the Ryukyus, Okinawa, Japan.

Plant hormones and the circadian rhythm have been implicated in coordinated control of isoprene emission in plants. To gain insights into the signalling networks, foliar application of plant hormones was conducted in a native emitter, Ficus septica. Spraying of 50 muM jasmonic acid (JA) gradually decreased isoprene emission by 88% compared with initial levels within 5 days, and emission increased after relief from JA application. We further explored the molecular regulatory mechanism of isoprene emission by analysing photosynthetic rate, gene expression of 2-C-methyl-D-erythrytol 4-phosphate (MEP) pathway, hormone signalling and circadian rhythm processes, and metabolite pool sizes of MEP pathway. Results show that isoprene emission strongly correlated with isoprene synthase (IspS) gene expression and IspS protein levels over the period of JA treatment, indicating transcriptional and possible translational modulation of IspS by JA. Application of JA coordinately modulated genes in the auxin, cytokinin (CK), and circadian rhythm signal transduction pathways. Among the transcriptional factors analysed, MYC2 (JA) and LHY (circadian clock) negatively correlated with isoprene emission. Putative cis-elements predicted on IspS promoter (G-box for MYC2 and circadian for LHY) supports our proposal that isoprene emission is regulated by coordinated transcriptional modulation of IspS gene by phytohormone and circadian rhythm signalling.

PMID: 30610754

Plant Cell Environ , IF:6.362 , 2019 May , V42 (5) : P1458-1470 doi: 10.1111/pce.13504

Waterlogging-induced adventitious root formation in cucumber is regulated by ethylene and auxin through reactive oxygen species signalling.

Qi, Xiaohua and Li, Qianqian and Ma, Xiaotian and Qian, Chunlu and Wang, Huihui and Ren, Nannan and Shen, Chenxi and Huang, Shumiao and Xu, Xuewen and Xu, Qiang and Chen, Xuehao

Department of Horticulture, School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.; Department of Food Science, School of Food Science and Engineering, Yangzhou University, Yangzhou, China.

Development of adventitious roots (ARs) at the base of the shoot is an important adaptation of plants to waterlogging stress; however, its physiological mechanisms remain unclear. Here, we investigated the regulation of AR formation under waterlogged conditions by hormones and reactive oxygen species (ROS) in Cucumis sativus L., an agriculturally and economically important crop in China. We found that ethylene, auxin, and ROS accumulated in the waterlogged cucumber plants. On the other hand, application of the ethylene receptor inhibitor 1-methylcyclopropene (1-MCP), the auxin transport inhibitor 1-naphthylphthalamic acid (NPA), or the NADPH oxidase inhibitor diphenyleneiodonium (DPI) decreased the number of ARs induced by waterlogging. Auxin enhanced the expression of ethylene biosynthesis genes, which led to ethylene entrapment in waterlogged plants. Both ethylene and auxin induced the generation of ROS. Auxin-induced AR formation was inhibited by 1-MCP, although ethylene-induced AR formation was not inhibited by NPA. Both ethylene- and auxin-induced AR formation were counteracted by DPI. These results indicate that auxin-induced AR formation is dependent on ethylene, whereas ethylene-induced AR formation is independent of auxin. They also show that ROS signals mediate both ethylene- and auxin-induced AR formation in cucumber plants.

PMID: 30556134

Plant Cell Environ , IF:6.362 , 2019 May , V42 (5) : P1441-1457 doi: 10.1111/pce.13492

Phosphatidylinositol-specific phospholipase C2 functions in auxin-modulated root development.

Chen, Xi and Li, Lin and Xu, Buxian and Zhao, Shujuan and Lu, Piaoying and He, Yuqing and Ye, Tiantian and Feng, Yu-Qi and Wu, Yan

State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.; Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, China.

Nine phosphatidylinositol-specific phospholipases C (PLCs) have been identified in the Arabidopsis genome; among the importance of PLC2 in reproductive development is significant. However, the role of PLC2 in vegetative development such as in root growth is elusive. Here, we report that plc2 mutants displayed multiple auxin-defective phenotypes in root development, including short primary root, impaired root gravitropism, and inhibited root hair growth. The DR5:GUS expression and the endogenous indole-3-acetic acid (IAA) content, as well as the responses of a set of auxin-related genes to exogenous IAA treatment, were all decreased in plc2 seedlings, suggesting the influence of PLC2 on auxin accumulation and signalling. The root elongation of plc2 mutants was less sensitive to the high concentration of exogenous auxins, and the application of 1-naphthaleneacetic acid or the auxin transport inhibitor N-1-naphthylphthalamic acid could rescue the root hair growth of plc2 mutants. In addition, the PIN2 polarity and cycling in plc2 root epidermis cells were altered. These results demonstrate a critical role of PLC2 in auxin-mediated root development in Arabidopsis, in which PLC2 influences the polar distribution of PIN2.

PMID: 30496625

Plant J , IF:6.141 , 2019 May , V98 (3) : P524-539 doi: 10.1111/tpj.14236

A CACTA-like transposable element in the upstream region of BnaA9.CYP78A9 acts as an enhancer to increase silique length and seed weight in rapeseed.

Shi, Liuliu and Song, Jurong and Guo, Chaocheng and Wang, Bo and Guan, Zhilin and Yang, Pu and Chen, Xun and Zhang, Qinghua and King, Graham J and Wang, Jing and Liu, Kede

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.; Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2480, Australia.

Rapeseed (Brassica napus L.) is a model plant for polyploid crop research and the second-leading source of vegetable oil worldwide. Silique length (SL) and seed weight are two important yield-influencing traits in rapeseed. Using map-based cloning, we isolated qSLWA9, which encodes a P450 monooxygenase (BnaA9.CYP78A9) and functions as a positive regulator of SL. The expression level of BnaA9.CYP78A9 in silique valves of the long-silique variety is much higher than that in the regular-silique variety, which results in elongated cells and a prolonged phase of silique elongation. Plants of the long-silique variety and transgenic plants with high expression of BnaA9.CYP78A9 had a higher concentration of auxin in the developing silique; this induced a number of auxin-related genes but no genes in well-known auxin biosynthesis pathways, suggesting that BnaA9.CYP78A9 may influence auxin concentration by affecting auxin metabolism or an unknown auxin biosynthesis pathway. A 3.7-kb CACTA-like transposable element (TE) inserted in the 3.9-kb upstream regulatory sequence of BnaA9.CYP78A9 elevates the expression level, suggesting that the CACTA-like TE acts as an enhancer to stimulate high gene expression and silique elongation. Marker and sequence analysis revealed that the TE in B. napus had recently been introgressed from Brassica rapa by interspecific hybridization. The insertion of the TE is consistently associated with long siliques and large seeds in both B. napus and B. rapa collections. However, the frequency of the CACTA-like TE in rapeseed varieties is still very low, suggesting that this allele has not been widely used in rapeseed breeding programs and would be invaluable for yield improvement in rapeseed breeding.

PMID: 30664290

J Exp Bot , IF:5.908 , 2019 May , V70 (10) : P2609-2614 doi: 10.1093/jxb/erz111

Non-canonical auxin signalling: fast and curious.

Kubes, Martin and Napier, Richard

School of Live Sciences, University of Warwick, Coventry, UK.; Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacky University, Slechtitelu, Olomouc, Czech Republic.; University Hradec Kralove, Faculty of Science, Department of Biology, Rokitanskeho, CZ-50003 Hradec Kralove, Czech Republic.

PMID: 30854547

Ecotoxicol Environ Saf , IF:4.872 , 2019 May , V172 : P380-387 doi: 10.1016/j.ecoenv.2019.01.069

Cadmium stress increases antioxidant enzyme activities and decreases endogenous hormone concentrations more in Cd-tolerant than Cd-sensitive wheat varieties.

Guo, Jiajia and Qin, Shiyu and Rengel, Zed and Gao, Wei and Nie, Zhaojun and Liu, Hongen and Li, Chang and Zhao, Peng

College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou 450002, China.; Department of Agriculture and Environmental Sciences, the University of Western Australia, Perth 6000, Australia.; College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou 450002, China. Electronic address: zhaopeng@henau.edu.cn.

The different wheat varieties have different tolerance to cadmium stress, while the mechanisms underlying the Cd tolerance are still poorly understood. A pot experiment was conducted to study the changes of antioxidant enzyme activities and endogenous hormones in wheat (Triticum aestivum) genotypes differing in cadmium (Cd) accumulation (low = Pingan 8 and high = Bainong 160) in different growth stages under Cd stress. The Cd treatment (3mg/kg) increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and concentrations of malondialdehyde (MDA) and abscisic acid (ABA); in contrast, it reduced the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular carbon dioxide concentration (Ci) and the concentrations of gibberellin (GA3), auxin (IAA) and zeatin nucleoside (ZR) in wheat leaves compared to the CK (without Cd). The antioxidant enzyme activities were higher in Bainong 160 than Pingan 8 under Cd stress. In addition, the changes in endogenous hormone concentration were smaller in Bainong 160 than Pingan 8 leaves. The correlation coefficients of Bainong 160 and Pingan 8 were 0.87 and 0.66, respectively. Our results suggest that high Cd accumulation (greater Cd tolerance) in Bainong 160 is associated with higher photosynthetic parameters, higher activities of antioxidant enzyme and higher concentration of hormones than Pingan 8.

PMID: 30731269

Int J Mol Sci , IF:4.556 , 2019 May , V20 (10) doi: 10.3390/ijms20102567

Mutations in the Rice OsCHR4 Gene, Encoding a CHD3 Family Chromatin Remodeler, Induce Narrow and Rolled Leaves with Increased Cuticular Wax.

Guo, Tingting and Wang, Daofeng and Fang, Jingjing and Zhao, Jinfeng and Yuan, Shoujiang and Xiao, Langtao and Li, Xueyong

Hunan Provincial Key Laboratory of Phytohormones, Hunan Provincial Key Laboratory for Crop Germplasm Innovation and Utilization, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China. guoting0118@126.com.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. w2806047078@126.com.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. fangjingjing@caas.cn.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. zhaojinfeng@caas.cn.; Shandong Rice Research Institute, Jinan 250100, China. ysj868@sina.com.; Hunan Provincial Key Laboratory of Phytohormones, Hunan Provincial Key Laboratory for Crop Germplasm Innovation and Utilization, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China. langtaoxiao@163.com.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. lixueyong@caas.cn.

Leaf blade width, curvature, and cuticular wax are important agronomic traits of rice. Here, we report the rice Oschr4-5 mutant characterized by pleiotropic phenotypes, including narrow and rolled leaves, enhanced cuticular wax deposition and reduced plant height and tiller number. The reduced leaf width is caused by a reduced number of longitudinal veins and increased auxin content. The cuticular wax content was significantly higher in the Oschr4-5 mutant, resulting in reduced water loss rate and enhanced drought tolerance. Molecular characterization reveals that a single-base deletion results in a frame-shift mutation from the second chromodomain of OsCHR4, a CHD3 (chromodomain helicase DNA-binding) family chromatin remodeler, in the Oschr4-5 mutant. Expressions of seven wax biosynthesis genes (GL1-4, WSL4, OsCER7, LACS2, LACS7, ROC4 and BDG) and four auxin biosynthesis genes (YUC2, YUC3, YUC5 and YUC6) was up-regulated in the Oschr4-5 mutant. Chromatin immunoprecipitation assays revealed that the transcriptionally active histone modification H3K4me3 was increased, whereas the repressive H3K27me3 was reduced in the upregulated genes in the Oschr4-5 mutant. Therefore, OsCHR4 regulates leaf morphogenesis and cuticle wax formation by epigenetic modulation of auxin and wax biosynthetic genes expression.

PMID: 31130602

Int J Mol Sci , IF:4.556 , 2019 May , V20 (9) doi: 10.3390/ijms20092339

Involvement of BIG5 and BIG3 in BRI1 Trafficking Reveals Diverse Functions of BIG-subfamily ARF-GEFs in Plant Growth and Gravitropism.

Xue, Shan and Zou, Junjie and Liu, Yangfan and Wang, Ming and Zhang, Chunxia and Le, Jie

Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. xueshan1984@yeah.net.; University of Chinese Academy of Sciences, Beijing 100049, China. xueshan1984@yeah.net.; Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. zoujunjie@caas.cn.; Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. liuyangfan@ibcas.ac.cn.; University of Chinese Academy of Sciences, Beijing 100049, China. liuyangfan@ibcas.ac.cn.; Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. ming.wang@genefirst.com.; University of Chinese Academy of Sciences, Beijing 100049, China. ming.wang@genefirst.com.; Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. chunxia.zhang@ibcas.ac.cn.; Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. lejie@ibcas.ac.cn.

ADP-ribosylation factor-guanine nucleotide exchange factors (ARF-GEFs) act as key regulators of vesicle trafficking in all eukaryotes. In Arabidopsis, there are eight ARF-GEFs, including three members of the GBF1 subfamily and five members of the BIG subfamily. These ARF-GEFs have different subcellular localizations and regulate different trafficking pathways. Until now, the roles of these BIG-subfamily ARF-GEFs have not been fully revealed. Here, analysis of the BIGs expression patterns showed that BIG3 and BIG5 have similar expression patterns. big5-1 displayed a dwarf growth and big3-1 big5-1 double mutant showed more severe defects, indicating functional redundancy between BIG3 and BIG5. Moreover, both big5-1 and big3-1 big5-1 exhibited a reduced sensitivity to Brassinosteroid (BR) treatment. Brefeldin A (BFA)-induced BR receptor Brassinosteroid insensitive 1 (BRI1) aggregation was reduced in big5-1 mutant, indicating that the action of BIG5 is required for BRI1 recycling. Furthermore, BR-induced dephosphorylation of transcription factor BZR1 was decreased in big3-1 big5-1 double mutants. The introduction of the gain-of-function of BZR1 mutant BZR1-1D in big3-1 big5-1 mutants can partially rescue the big3-1 big5-1 growth defects. Our findings revealed that BIG5 functions redundantly with BIG3 in plant growth and gravitropism, and BIG5 participates in BR signal transduction pathway through regulating BRI1 trafficking.

PMID: 31083521

Theor Appl Genet , IF:4.439 , 2019 May , V132 (5) : P1435-1449 doi: 10.1007/s00122-019-03290-8

Identification and characterization of a new dwarf locus DS-4 encoding an Aux/IAA7 protein in Brassica napus.

Zhao, Bo and Wang, Bo and Li, Zhaohong and Guo, Tao and Zhao, Junwei and Guan, Zhilin and Liu, Kede

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China. kdliu@mail.hzau.edu.cn.

KEY MESSAGE: A dominant dwarfing gene, ds - 4 , encodes an Aux/IAA protein that negatively regulates plant stature through an auxin signaling pathway. Dwarfism is an important agronomic trait affecting yield in many crop species. The molecular mechanisms underlying dwarfism in oilseed rape (Brassica napus) are poorly understood, restricting the progress of breeding dwarf varieties in this species. Here, we identified and characterized a new dwarf locus, DS-4, in B. napus. Next-generation sequencing-assisted genetic mapping and candidate gene analysis found that DS-4 encodes a nucleus-targeted auxin/indole-3-acetic acid (Aux/IAA) protein. A substitution (P87L) was found in the highly conserved degron motif of the Aux/IAA7 protein in the ds-4 mutant. This mutation co-segregated with the phenotype of individuals in the BC1F2 population. The P87L substitution was confirmed as the cause of the extreme dwarf phenotype by ectopic expression of the mutant allele BnaC05.iaa7 (equivalent to ds-4) in Arabidopsis. The P87L substitution blocked the interaction of BnaC05.iaa7 with TRANSPORT INHIBITOR RESPONSE 1 in the presence of auxin. The BnaC05.IAA7 gene is highly expressed in the cotyledons, hypocotyls, stems and leaves, but weakly in the roots and seeds of B. napus. Our findings provide new insights into the molecular mechanisms underlying dominant (gain-of-function) dwarfism in B. napus. Our identification of a distinct gene locus controlling plant height may help to improve lodging resistance in oilseed rape.

PMID: 30688990

Plant Cell Physiol , IF:4.062 , 2019 May , V60 (5) : P1067-1081 doi: 10.1093/pcp/pcz024

A Comparison of sun, ovate, fs8.1 and Auxin Application on Tomato Fruit Shape and Gene Expression.

Wang, Yanping and Clevenger, Josh P and Illa-Berenguer, Eudald and Meulia, Tea and van der Knaap, Esther and Sun, Liang

College of Horticulture, China Agricultural University, Beijing, P.R. China.; Department of Horticulture and Crop Science, The Ohio State University/OARDC, Wooster, OH, USA.; National Engineering Research Center for Vegetables, Beijing Academy of Agriculture and Forestry Sciences, Beijing, P.R. China.; Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Athens, GA, USA.; Center for Applied Genetic Technologies, Mars Wrigley Confectionery, Athens, GA, USA.; Center for Applied Genetic Technologies, University of Georgia, Athens, GA, USA.; Department of Plant Pathology, Molecular and Cellular Imaging Center, The Ohio State University/OARDC, Wooster, OH, USA.; Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing, P.R. China.

Elongated tomato fruit shape is the result of the action of the fruit shape genes possibly in coordination with the phytohormone auxin. To investigate the possible link between auxin and the fruit shape genes, a series of auxin (2,4-D) treatments were performed on the wild-type and the fruit shape near-isogenic lines (NILs) in Solanum pimpinellifolium accession LA1589 background. Morphological and histological analyses indicated that auxin application approximately 3 weeks before anthesis led to elongated pear-shaped ovaries and fruits, which was mainly attributed to the increase of ovary/fruit proximal end caused by the increase of both cell number and cell size. Fruit shape changes caused by SUN, OVATE and fs8.1 were primarily due to the alterations of cell number along different growth axes. Particularly, SUN caused elongation by extending cell number along the entire proximal-distal axis, whereas OVATE caused fruit elongation in the proximal area, which was most similar to the effect of auxin on ovary shape. Expression analysis of flower buds at different stages in fruit shape NILs indicated that SUN had a stronger impact on the transcriptome than OVATE and fs8.1. The sun NIL differentially expressed genes were enriched in several biological processes, such as lipid metabolism, ion transmembrane and actin cytoskeleton organization. Additionally, SUN also shifted the expression of the auxin-related genes, including those involved in auxin biosynthesis, homeostasis, signal transduction and polar transport, indicating that SUN may regulate ovary/fruit shape through modifying the expression of auxin-related genes very early during the formation of the ovary in the developing flower.

PMID: 30753610

Plant Cell Physiol , IF:4.062 , 2019 May , V60 (5) : P935-944 doi: 10.1093/pcp/pcz005

Brassinosteroid Induces Phosphorylation of the Plasma Membrane H+-ATPase during Hypocotyl Elongation in Arabidopsis thaliana.

Minami, Anzu and Takahashi, Koji and Inoue, Shin-Ichiro and Tada, Yasuomi and Kinoshita, Toshinori

Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya, Japan.; Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, Japan.; Center for Gene Research, Nagoya University, Nagoya, Japan.

Brassinosteroids (BRs) are steroid phytohormones that regulate plant growth and development, and promote cell elongation at least in part via the acid-growth process. BRs have been suggested to induce cell elongation by the activating plasma membrane (PM) H+-ATPase. However, the mechanism by which BRs activate PM H+-ATPase has not been clarified. In this study, we investigated the effects of BR on hypocotyl elongation and the phosphorylation status of a penultimate residue, threonine, of PM H+-ATPase, which affects the activation, in the etiolated seedlings of Arabidopsis thaliana. Brassinolide (BL), an active endogenous BR, induced hypocotyl elongation, phosphorylation of the penultimate, threonine residue of PM H+-ATPase, and binding of the 14-3-3 protein to PM H+-ATPase in the endogenous BR-depleted seedlings. Changes in both BL-induced elongation and phosphorylation of PM H+-ATPase showed similar concentration dependency. BL did not induce phosphorylation of PM H+-ATPase in the BR receptor mutant bri1-6. In contrast, bikinin, a specific inhibitor of BIN2 that acts as a negative regulator of BR signaling, induced its phosphorylation. Furthermore, BL accumulated the transcripts of SMALL AUXIN UP RNA 9 (SAUR9) and SAUR19, which suppress dephosphorylation of the PM H+-ATPase penultimate residue by inhibiting D-clade type 2C protein phosphatase in the hypocotyls of etiolated seedlings. From these results, we conclude that BL-induced phosphorylation of PM H+-ATPase penultimate residue is mediated via the BRI1-BIN2 signaling pathway, together with the accumulation of SAURs during hypocotyl elongation.

PMID: 30649552

Rice (N Y) , IF:3.912 , 2019 May , V12 (1) : P35 doi: 10.1186/s12284-019-0287-9

Comparative study of the mycorrhizal root transcriptomes of wild and cultivated rice in response to the pathogen Magnaporthe oryzae.

Tian, Lei and Chang, Chunling and Ma, Lina and Nasir, Fahad and Zhang, Jianfeng and Li, Weiqiang and Tran, Lam-Son Phan and Tian, Chunjie

Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China.; University of Chinese Academy of Sciences, Beijing, 100049, China.; School of Life Sciences, Northeast Normal University, Changchun City, Jilin, China.; College of Life Science, Jilin Agricultural University, Changchun, Jilin, China.; Stress Adaptation Research Unit, RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro-cho, Tsurumi, Yokohama, 230-0045, Japan.; Stress Adaptation Research Unit, RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro-cho, Tsurumi, Yokohama, 230-0045, Japan. tranplamson@duytan.edu.vn.; Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang, 550000, Vietnam. tranplamson@duytan.edu.vn.; Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China. tiancj@neigae.ac.cn.

BACKGROUND: Rice, which serves as a staple food for more than half of the world's population, is very susceptible to the pathogenic fungus, Magnaporthe oryzae. However, common wild rice (Oryza rufipogon), which is the ancestor of Asian cultivated rice (O. sativa), has significant potential as a genetic source of resistance to M. oryzae. Recent studies have shown that the domestication of rice has altered its relationship to symbiotic arbuscular mycorrhizae. A comparative response of wild and domestic rice inhabited by mycorrhizae to infection by M. oryzae has not been documented. RESULTS: In the current study, roots of wild and cultivated rice colonized with the arbuscular mycorrhizal (AM) fungus (AMF) Rhizoglomus intraradices were used to compare the transcriptomic responses of the two species to infection by M. oryzae. Phenotypic analysis indicated that the colonization of wild and cultivated rice with R. intraradices improved the resistance of both genotypes to M. oryzae. Wild AM rice, however, was more resistant to M. oryzae than the cultivated AM rice, as well as nonmycorrhizal roots of wild rice. Transcriptome analysis indicated that the mechanisms regulating the responses of wild and cultivated AM rice to M. oryzae invasion were significantly different. The expression of a greater number of genes was changed in wild AM rice than in cultivated AM rice in response to the pathogen. Both wild and cultivated AM rice exhibited a shared response to M. oryzae which included genes related to the auxin and salicylic acid pathways; all of these play important roles in pathogenesis-related protein synthesis. In wild AM rice, secondary metabolic and biotic stress-related analyses indicated that the jasmonic acid synthesis-related alpha-linolenic acid pathway, the phenolic and terpenoid pathways, as well as the phenolic and terpenoid syntheses-related mevalonate (MVA) pathway were more affected by the pathogen. Genes related to these pathways were more significantly enriched in wild AM rice than in cultivated AM rice in response to M. oryzae. On the other hand, genes associated with the 'brassinosteroid biosynthesis' were more enriched in cultivated AM rice. CONCLUSIONS: The AMF R. intraradices-colonized rice plants exhibited greater resistance to M. oryzae than non-AMF-colonized plants. The findings of the current study demonstrate the potential effects of crop domestication on the benefits received by the host via root colonization with AMF(s), and provide new information on the underlying molecular mechanisms. In addition, results of this study can also help develop guidelines for the applications of AMF(s) when planting rice.

PMID: 31076886

BMC Genomics , IF:3.594 , 2019 May , V20 (1) : P421 doi: 10.1186/s12864-019-5760-8

Identification and profiling of upland cotton microRNAs at fiber initiation stage under exogenous IAA application.

Zhao, Tianlun and Xu, Xiaojian and Wang, Min and Li, Cheng and Li, Cong and Zhao, Rubing and Zhu, Shuijin and He, Qiuling and Chen, Jinhong

Department of Agronomy, Zhejiang University, Zhejiang, 310058, Hangzhou, China.; Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China. qlhe@zstu.edu.cn.; Department of Agronomy, Zhejiang University, Zhejiang, 310058, Hangzhou, China. jinhongchen@zju.edu.cn.

BACKGROUND: Cotton is the most essential textile crop worldwide, and phytohormones are critical for cotton fiber development. One example is the role of auxin in fiber initiation, but we know little molecular basis. MicroRNAs (miRNAs) have a significant function in cotton development; nevertheless their role in fiber initiation remains unclear. Here, exogenous IAA was applied to cotton plant before anthesis. Utilizing small RNA sequencing, the mechanism underlying miRNA-mediated regulation of fiber initiation under exogenous IAA treatment was investigated. RESULTS: With exogenous IAA application, the endogenous IAA and GA contents of IAA treated (IT) ovules were higher than control (CK) ovules at the fiber initiation stage, while endogenous ABA content was lower in IT than CK. Using scanning electron microscopy, we found the fiber number and size were significantly promoted in IT at 0 DPA. Fiber quality analysis showed that fiber length, uniformity, strength, elongation, and micronaire of IT were higher than CK, though not statistically significant, while lint percent was significantly higher in IT. We generated six small RNA libraries using - 3, 0, and 3 DPA ovules of IT and CK, and identified 58 known miRNAs and 83 novel miRNAs together with the target genes. The differential expressed miRNAs number between IT and CK at - 3, 0, 3 DPA was 34, 16 and 24, respectively. Gene ontology and KEGG pathway enrichment analyses for the target genes of the miRNAs expressed in a differential manner showed that they were significantly enriched in 30 terms and 8 pathways. QRT-PCR for those identified miRNAs and the target genes related to phytohormones and fiber development was performed, and results suggested a potential role of these miRNAs in fiber initiation. CONCLUSIONS: The exogenous IAA application affected the relative phytohormone contents in ovule and promoted fiber initiation in cotton. Identification and profiling of miRNAs and their targets at the fiber initiation stage provided insights for miRNAs' regulation function of fiber initiation. These findings not only shed light on the regulatory network of fiber growth but also offer clues for cotton fiber amelioration strategies in cotton.

PMID: 31138116

BMC Plant Biol , IF:3.497 , 2019 May , V19 (1) : P229 doi: 10.1186/s12870-019-1847-2

Transcriptional regulation of MdPIN3 and MdPIN10 by MdFLP during apple self-rooted stock adventitious root gravitropism.

Wang, Zenghui and Li, Jialin and Mao, Yunfei and Zhang, Manman and Wang, Rong and Hu, Yanli and Mao, Zhiquan and Shen, Xiang

State Key Laboratory of Crop Biology; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Huanghuai Region), Ministry of Agriculture; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China.; State Key Laboratory of Crop Biology; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Huanghuai Region), Ministry of Agriculture; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China. hainandaousyd@163.com.

BACKGROUND: The close planting of dwarfing self-rooted rootstocks is currently a widely used method for apple production; however, self-rooted rootstocks are weak with shallow roots and poor grounding. Therefore, understanding the molecular mechanisms that establish the gravitropic set-point angles (GSAs) of the adventitious roots of self-rooted apple stocks is important for developing self-rooted apple rootstock cultivars with deep roots. RESULTS: We report that the apple FOUR LIPS (MdFLP), an R2R3-MYB transcription factor (TF), functions in establishing the GSA of the adventitious roots of self-rooted apple stocks in response to gravity. Biochemical analyses demonstrate that MdFLP directly binds to the promoters of two auxin efflux carriers, MdPIN3 and MdPIN10, that are involved in auxin transport, activates their transcriptional expression, and thereby promotes the development of adventitious roots in self-rooted apple stocks. Additionally, the apple auxin response factor MdARF19 influences the expression of those auxin efflux carriers and the establishment of the GSA of adventitious roots of apple in response to gravity by directly activating the expression of MdFLP. CONCLUSION: Our findings provide new insights into the transcriptional regulation of MdFLP by the auxin response factor MdARF19 in the regulation of the GSA of adventitious roots of self-rooted apple stocks in response to gravity.

PMID: 31146692

BMC Plant Biol , IF:3.497 , 2019 May , V19 (1) : P197 doi: 10.1186/s12870-019-1808-9

Characterization of phytohormone and transcriptome reprogramming profiles during maize early kernel development.

Ma, Chuanyu and Li, Bo and Wang, Lina and Xu, Ming-Liang and Lizhu, E and Jin, Hongyu and Wang, Zhicheng and Ye, Jian-Rong

National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193, People's Republic of China.; National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193, People's Republic of China. yejr2006@cau.edu.cn.

BACKGROUND: During maize early kernel development, the dramatic transcriptional reprogramming determines the rate of developmental progression, and phytohormone plays critical role in these important processes. To investigate the phytohormone levels and transcriptome reprogramming profiles during maize early kernel development, two maize inbreds with similar genetic background but different mature kernel sizes (ILa and ILb) were used. RESULTS: The levels of indole-3-acetic acid (IAA) were increased continuously in maize kernels from 5 days after pollination (DAP) to 10 DAP. ILa had smaller mature kernels than ILb, and ILa kernels had significantly lower IAA levels and significantly higher SA levels than ILb at 10 DAP. The different phytohormone profiles correlated with different transcriptional reprogramming in the two kernels. The global transcriptomes in ILa and ILb kernels were strikingly different at 5 DAP, and their differences peaked at 8 DAP. Functional analysis showed that the biggest transcriptome difference between the two kernels is those response to biotic and abiotic stresses. Further analyses indicated that the start of dramatic transcriptional reprogramming and the onset of significantly enriched functional categories, especially the "plant hormone signal transduction" and "starch and sucrose metabolism", was earlier in ILa than in ILb, whereas more significant enrichment of those functional categories occurred at later stage of kernel development in ILb. CONCLUSIONS: These results indicate that later onset of the significantly enriched functional categories, coincide with their stronger activities at a later developmental stage and higher IAA level, are necessary for young kernels to undergo longer mitotic activity and finally develop a larger kernel size. The different onset times and complex interactions of the important functional categories, especially phytohormone signal, and carbohydrate metabolism, form the most important molecular regulators mediating maize early kernel development.

PMID: 31088353

BMC Plant Biol , IF:3.497 , 2019 May , V19 (1) : P194 doi: 10.1186/s12870-019-1794-y

Identification of key genes and its chromosome regions linked to drought responses in leaves across different crops through meta-analysis of RNA-Seq data.

Benny, Jubina and Pisciotta, Antonino and Caruso, Tiziano and Martinelli, Federico

Dipartimento di Scienze Agrarie Alimentari e Forestali, Universita degli Studi di Palermo, viale delle scienze ed. 4, Palermo, 90128, Italy.; Dipartimento di Biologia, Universita degli Studi di Firenze, Via Madonna del Piano 6, Sesto Fiorentino, FI, 50019, Italy. federico.martinelli@unifi.it.

BACKGROUND: Our study is the first to provide RNA-Seq data analysis related to transcriptomic responses towards drought across different crops. The aim was to identify and map which genes play a key role in drought response on leaves across different crops. Forty-two RNA-seq samples were analyzed from 9 published studies in 7 plant species (Arabidopsis thaliana, Solanum lycopersicum, Zea mays, Vitis vinifera, Malus X domestica, Solanum tuberosum, Triticum aestivum). RESULTS: Twenty-seven (16 up-regulated and 11 down-regulated) drought-regulated genes were commonly present in at least 7 of 9 studies, while 351 (147 up-regulated and 204 down-regulated) were commonly drought-regulated in 6 of 9 studies. Across all kind of leaves, the drought repressed gene-ontologies were related to the cell wall and membrane re-structuring such as wax biosynthesis, cell wall organization, fatty acid biosynthesis. On the other hand, drought-up-regulated biological processes were related to responses to osmotic stress, abscisic acid, water deprivation, abscisic-activated signalling pathway, salt stress, hydrogen peroxide treatment. A common metabolic feature linked to drought response in leaves is the repression of terpenoid pathways. There was an induction of AL1 (alfin-like), UGKYAH (trihelix), WRKY20, homeobox genes and members of the SET domain family in 6 of 9 studies. Several genes involved in detoxifying and antioxidant reactions, signalling pathways and cell protection were commonly modulated by drought across the 7 species. The chromosome (Chr) mapping of these key abiotic stress genes highlighted that Chr 4 in Arabidopsis thaliana, Chr 1 in Zea mays, Chr 2 and Chr 5 in Triticum aestivum contained a higher presence of drought-related genes compared to the other remaining chromosomes. In seedling studies, it is worth notice the up-regulation of ERF4 and ESE3 (ethylene), HVA22 (abscisic acid), TIR1 (auxin) and some transcription factors (MYB3, MYB94, MYB1, WRKY53 and WRKY20). In mature leaves, ERF1 and Alfin-like 1 were induced by drought while other transcription factors (YABBY5, ARR2, TRFL2) and genes involved phospholipid biosynthesis were repressed. CONCLUSIONS: The identified and mapped genes might be potential targets of molecular breeding activities to develop cultivars with enhanced drought resistance and tolerance across different crops.

PMID: 31077147

BMC Plant Biol , IF:3.497 , 2019 May , V19 (1) : P192 doi: 10.1186/s12870-019-1792-0

Integrated analysis of mRNA-seq and miRNA-seq in calyx abscission zone of Korla fragrant pear involved in calyx persistence.

Ma, Li and Zhou, Li and Quan, Shaowen and Xu, Hang and Yang, Jieping and Niu, Jianxin

Department of Horticulture, College of Agriculture, Shihezi University, Shihezi, 832003, Xinjiang, China.; Xinjiang Production and Construction Corps Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization, Shihezi, 832003, Xinjiang, China.; Department of Horticulture, College of Agriculture, Shihezi University, Shihezi, 832003, Xinjiang, China. njx105@163.com.; Xinjiang Production and Construction Corps Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization, Shihezi, 832003, Xinjiang, China. njx105@163.com.

BACKGROUND: The objective of this study was to characterize molecular mechanism of calyx persistence in Korla fragrant pear by transcriptome and small RNA sequencing. Abscission zone tissues of flowers at three stages (the first, fifth and ninth days of the late bloom stage), with 50 mg/L GA3 (calyx persistence treatment, C_1, C_5, C_9) or 500 mg/L PP333 (calyx abscission treatment, T_1, T_5, T_9), were collected and simultaneously conducted transcriptome and small RNA sequencing. RESULTS: Through association analysis of transcriptome and small RNA sequencing, mRNA-miRNA network was conducted. Compared calyx persistence groups with calyx abscission groups during the same stage, 145, 56 and 150 mRNA-miRNA pairs were obtained in C_1 vs T_1, C_5 vs T_5 and C_9 vs T_9, respectively; When C_1 compared with C_5 and C_9, 90 and 506 mRNA-miRNA pairs were screened respectively, and 255 mRNA-miRNA pairs were obtained from the comparison between C_5 and C_9; When T_1 compared with the T_5 and T_9, respectively, 206 and 796 mRNA-miRNA pairs were obtained, and 383 mRNA-miRNA pairs were obtained from the comparison between T_5 and T_9. These mRNAs in miRNA-mRNA pairs were significantly enriched into the terpenoid backbone biosynthesis, photosynthesis - antenna proteins, porphyrin and chlorophyll metabolism, carotenoid biosynthesis, zeatin biosynthesis and plant hormone signal transduction. In addition, we obtained some key genes from miRNA-mRNA pairs that may be associated with calyx abscission, including protein phosphatase 2C (psi-miR394a-HAB1), receptor-like protein kinase (psi-miR396a-5p-HERK1), cellulose synthase-like protein D3 (psi-miR827-CSLD3), beta-galactosidase (psi-miR858b-beta-galactosidase), SPL-psi-miR156j/157d, abscisic acid 8'-hydroxylase 1 (psi-miR396a-5p-CYP707A1) and auxin response factor (psi-miR160a-3p-ARF6, psi-miR167d-ARF18, psi-miR167a-5p-ARF25), etc. CONCLUSION: By integrated analysis mRNA and miRNA, our study gives a better understanding of the important genes and regulation pathway related to calyx abscission in Korla fragrant pear. We have also established the network of miRNA-mRNA pairs to learn about precise regulation of miRNA on calyx abscission.

PMID: 31072362

Planta , IF:3.39 , 2019 May , V249 (5) : P1449-1463 doi: 10.1007/s00425-018-03074-2

Effects of exogenous 24-epibrassinolide and brassinazole on negative gravitropism and tension wood formation in hybrid poplar (Populus deltoids x Populus nigra).

Gao, Junlan and Yu, Min and Zhu, Shiliu and Zhou, Liang and Liu, Shengquan

School of Forestry and Landscape Architecture, Anhui Agricultural University, Hefei, 230036, Anhui, People's Republic of China.; School of Forestry and Landscape Architecture, Anhui Agricultural University, Hefei, 230036, Anhui, People's Republic of China. liusq@ahau.edu.cn.

MAIN CONCLUSION: Exogenous 24-epibrassinolide (BL) and brassinazole (BRZ) have regulatory roles in G-fiber cell wall development and secondary xylem cell wall carbohydrate biosynthesis during tension wood formation in hybrid poplar. Brassinosteroids (BRs) play important roles in regulating gravitropism and vasculature development. Here, we report the effect of brassinosteroids on negative gravitropism and G-fiber cell wall development of the stem in woody angiosperms. We applied exogenous 24-epibrassinolide (BL) or its biosynthesis inhibitor brassinazole (BRZ) to slanted hybrid poplar trees (Populus deltoids x Populus nigra) and measured the morphology of gravitropic stems, anatomy and chemistry of secondary cell wall. We furthermore analyzed the expression levels of auxin transport and cellulose biosynthetic genes after 24-epibrassinolide (BL) or brassinazole (BRZ) application. The BL-treated seedlings showed no negative gravitropism bending, whereas application of BRZ dramatically enhanced negative gravitropic bending. BL treatment stimulated secondary xylem fiber elongation and G-fiber formation on the upper side of stems but delayed G-fiber maturation. BRZ inhibited xylem fiber elongation but induced the production of more mature G-fibers on the upper side of stems. Wood chemistry analyses and immunolocalization demonstrated that BL and BRZ treatments increased the cellulose content and modified the deposition of cell wall carbohydrates including arabinose, galactose and rhamnose in the secondary xylem. The expression of cellulose biosynthetic genes, especially those related to cellulose microfibril deposition (PtFLA12 and PtCOBL4) was significantly upregulated in BL- and BRZ-treated TW stems compared with control stems. The significant differences of G-fibers development and negative gravitropism bending between 24-epibrassinolide (BL) and brassinazole (BRZ) application suggest that brassinosteroids are important for secondary xylem development during tension wood formation. Our findings provide potential insights into the mechanism by which BRs regulate G-fiber cell wall development to accomplish negative gravitropism in TW formation.

PMID: 30689054

Phytopathology , IF:3.234 , 2019 May , V109 (5) : P810-818 doi: 10.1094/PHYTO-06-18-0213-R

Understanding the Resistance Mechanism in Brassica napus to Clubroot Caused by Plasmodiophora brassicae.

Mei, Jiaqin and Guo, Zhen and Wang, Jinhua and Feng, Yuxia and Ma, Guanhua and Zhang, Chunyu and Qian, Wei and Chen, Guokang

1 College of Agronomy and Biotechnology, Southwest University, Chongqing 400716, China.; 2 Academy of Agricultural Sciences, Southwest University, Chongqing, China.; 3 College of Plant Protection, Southwest University, Chongqing 400716, China; and.; 4 College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, 430070, China.

Exploring the mechanism of plant resistance has become the basis for selection of resistance varieties but reports on revealing resistant mechanism in Brassica napus against Plasmodiophora brassicae are rare. In this study, RNA-seq was conducted in the clubroot-resistant B. napus breeding line ZHE-226 and in the clubroot-susceptible rapeseed cultivar Zhongshuang 11 at 0, 3, 6, 9, and 12 days after inoculation. Strong alteration was detected specifically in ZHE-226 as soon as the root hair infection happened, and significant promotion was found in ZHE-226 on cell division or cell cycle, DNA repair and synthesis, protein synthesis, signaling, antioxidation, and secondary metabolites. Combining results from physiological, biochemical, and histochemical assays, our study highlights an effective signaling in ZHE-226 in response to P. brassicae. This response consists of a fast initiation of receptor kinases by P. brassicae; the possible activation of host intercellular G proteins which might, together with an enhanced Ca(2+) signaling, promote the production of reactive oxygen species; and programmed cell death in the host. Meanwhile, a strong ability to maintain homeostasis of auxin and cytokinin in ZHE-226 might effectively limit the formation of clubs on host roots. Our study provides initial insights into resistance mechanism in rapeseed to P. brassicae.

PMID: 30614377

J Plant Physiol , IF:3.013 , 2019 May , V236 : P117-123 doi: 10.1016/j.jplph.2019.03.008

Adventitious rooting of Chrysanthemum is stimulated by a low red:far-red ratio.

Christiaens, Annelies and Gobin, Bruno and Van Huylenbroeck, Johan and Van Labeke, Marie-Christine

PCS Ornamental Plant Research, Schaessestraat 18, B-9070 Destelbergen, Belgium; Ghent University, Faculty of Bioscience Engineering, Department Plants and Crops, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: annelies.christiaens@pcsierteelt.be.; PCS Ornamental Plant Research, Schaessestraat 18, B-9070 Destelbergen, Belgium. Electronic address: bruno.gobin@pcsierteelt.be.; Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Caritasstraat 39, B-9090 Melle, Belgium. Electronic address: johan.vanhuylenbroeck@ilvo.vlaanderen.be.; Ghent University, Faculty of Bioscience Engineering, Department Plants and Crops, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: mariechristine.vanlabeke@ugent.be.

Adventitious rooting, a critical process in the vegetative propagation of many ornamentals, can be affected by both light intensity and light quality. We investigated the use of spectral light quality to improve adventitious rooting of Chrysanthemum morifolium cuttings by applying different combinations of blue, red and far-red light. Additionally, unrooted cuttings were treated before planting with two auxin transport inhibitors (TIBA and NPA) to study the effect of light quality on auxin biosynthesis and/or transport. Results showed that lowering the R:FR ratio (decreasing the phytochrome photostationary state, PSS) improved rooting significantly and decreased the inhibiting effect of the auxin transport inhibitor NPA. An extra decrease of PSS by adding blue light to a red + far-red spectrum further enhanced rooting. In contrast, adding blue light to solely red light decreased rooting, an effect which was more pronounced in combination with the auxin transport inhibitors TIBA and NPA. Our results show that phytochrome plays a role in adventitious root formation through the action of auxin, but that also blue light receptors interact in this process.

PMID: 30974405

J Plant Physiol , IF:3.013 , 2019 May , V236 : P51-60 doi: 10.1016/j.jplph.2019.02.014

Spatio-temporal IAA gradient is determined by interactions with ET and governs flower abscission.

Kucko, Agata and Wilmowicz, Emilia and Ostrowski, Maciej

Chair of Plant Physiology and Biotechnology, Nicolaus Copernicus University, 1 LwowskaStreet, 87-100, Torun, Poland; Chair of Plant Physiology and Biotechnology, University of Gdansk, 59 Wita Stwosza, 80-308 Gdansk, Poland. Electronic address: kuckoa@poczta.onet.pl.; Chair of Plant Physiology and Biotechnology, Nicolaus Copernicus University, 1 LwowskaStreet, 87-100, Torun, Poland. Electronic address: emwil@umk.pl.; Department of Biochemistry, Nicolaus Copernicus University, 1 LwowskaStreet, 87-100, Torun, Poland. Electronic address: maciejost@umk.pl.

The abscission zone (AZ) is a specialized tissue that usually develops at the base of an organ and is highly sensitive to phytohormones, e.g., abscisic acid (ABA), ethylene (ET), and gibberellins (GAs). A current model of organ abscission assumes that the formation of an auxin gradient around the AZ area determines the time of shedding; however, that thesis is supported by studies that are primarily concerned with auxin transporters. To better understand the events underlying the progression of abscission, we focused for the first time on indole-3-acetic acid (IAA) distribution following AZ activation. We performed a series of immunolocalization studies in proximal and distal regions of floral AZ cells in yellow lupine, which is an agriculturally important legume. The examined phytohormone was abundant in natural active AZ cells, as well as above and below parts of this structure. A similar gradient of IAA was observed during the early steps of abscission, which was induced artificially by flower removal. Surprisingly, IAA was not detected in inactive AZ cells. This paper is also a consequence of our comprehensive studies concerning the phytohormonal regulation of flower abscission in yellow lupine. We present new data on interactions between IAA and ET, previously pointed out as a strong modulator of flower separation. The detailed analysis shows that disruption of the natural auxin gradient around the AZ area through the application of synthetic IAA had a positive effect on ET biosynthesis genes. We proved that these changes are accompanied by an accumulation of the ET precursor. On the other hand, exposure to ET significantly affected IAA localization in the whole AZ area in a time-dependent manner. Our results provide insight into the existence of a spatio-temporal sequential pattern of the IAA gradient related to the abscission process; this pattern is maintained by interactions with ET. We present new valuable evidence for the existence of conservative mechanisms that regulate generative organ separation and can help to improve the yield of agronomically significant species in the future.

PMID: 30878877

J Plant Physiol , IF:3.013 , 2019 May , V236 : P39-50 doi: 10.1016/j.jplph.2019.03.002

Cloning and expression analysis of LoCCD8 during IAA-induced bulbils outgrowth in lily (Oriental Hybrid 'Sorbonne').

Li, Jingrui and Chai, Min and Zhu, Xiaopei and Zhang, Xuhong and Li, Hui and Wang, Di and Xing, Quan and Zhang, Jinzheng and Sun, Meiyu and Shi, Lei

Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China.; Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.; Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: sunmeiyu@ibcas.ac.cn.; Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: shilei_67@126.com.

Aerial bulbils, which resemble tiny bulbs, develop from axillary buds and facilitate rapid propagation of Lilium. In most species of lily, bulbils are perpetually dormant and little is known about induction of these vegetative structures. Herein, we proposed that strigolactones (SLs) may regulate the induction of bulbils in Lilium. We tested this hypothesis by isolating and investigating the expression patterns of 2 copies of the carotenoid cleavage dioxygenase8 (CCD8) gene in lily-LoCCD8a and LoCCD8b-with regard to biosynthesis of SLs. Expression analyses revealed that LoCCD8a principally is expressed during vegetative growth, whereas LoCCD8b mainly is expressed during reproductive growth. The maximum quantity of LoCCD8a transcripts was observed in the basal plate in most developmental stages, which suggests that SLs may originate from underground parts, especially the basal plate, and move upward. The effects of treatments with indole-3-acetic acid or SL analog (GR24) on outgrowth of bulbils and expression of LoCCD8 genes suggested that SLs function downstream of auxin to inhibit the outgrowth of bulbil. The expression patterns of LoCCD8a and LoCCD8b at sprouting and bulblet weighting stages also implied that SLs may function in nutrient redistribution. Our findings are expected to promote the utilization of bulbils as vegetative propagules for commercial practice.

PMID: 30878012

World J Microbiol Biotechnol , IF:2.477 , 2019 May , V35 (6) : P90 doi: 10.1007/s11274-019-2659-0

A comparative analysis of exopolysaccharide and phytohormone secretions by four drought-tolerant rhizobacterial strains and their impact on osmotic-stress mitigation in Arabidopsis thaliana.

Ghosh, Daipayan and Gupta, Anshika and Mohapatra, Sridev

Department of Biological Sciences, Birla Institute of Technology and Science (Pilani), Hyderabad Campus, Hyderabad, Telangana, 500078, India.; Department of Biological Sciences, Birla Institute of Technology and Science (Pilani), Hyderabad Campus, Hyderabad, Telangana, 500078, India. sridev.mohapatra@hyderabad.bits-pilani.ac.in.

The ability of plant growth promoting rhizobacteria (PGPR) for imparting abiotic stress tolerance to plants has been widely explored in recent years; however, the diversity and potential of these microbes have not been maximally exploited. In this study, we characterized four bacterial strains, namely, Pseudomonas aeruginosa PM389, Pseudomonas aeruginosa ZNP1, Bacillus endophyticus J13 and Bacillus tequilensis J12, for potential plant growth promoting (PGP) traits under osmotic-stress, induced by 25% polyethylene glycol (PEG) in the growth medium. Growth curve analysis was performed in LB medium with or without PEG, in order to understand the growth patterns of these bacteria under osmotic-stress. All strains were able to grow and proliferate under osmotic-stress, although their growth rate was slower than that under non-stressed conditions (LB without PEG). Bacterial secretions were analyzed for the presence of exopolysaccharides and phytohormones and it was observed that all four strains released these compounds into the media, both, under stressed and non-stressed conditions. In the Pseudomonas strains, osmotic stress caused a decrease in the levels of auxin (IAA) and cytokinin (tZ), but an increase in the levels of gibberellic acid. The Bacillus strains on the other hand showed a stress-induced increase in the levels of all three phytohormones. P. aeruginosa ZNP1 and B. endophyticus J13 exhibited increased EPS production under osmotic-stress. While osmotic stress caused a decrease in the levels of EPS in P. aeruginosa PM389, B. tequilensis J12 showed no change in EPS quantities released into the media under osmotic stress when compared to non-stressed conditions. Upon inoculating Arabidopsis thaliana seedlings with these strains individually, it was observed that all four strains were able to ameliorate the adverse effects of osmotic-stress (induced by 25% PEG in MS-Agar medium) in the plants, as evidenced by their enhanced fresh weight, dry weight and plant water content, as opposed to osmotic-stressed, non-inoculated plants.

PMID: 31147784

J Plant Res , IF:2.185 , 2019 May , V132 (3) : P301-309 doi: 10.1007/s10265-019-01100-2

A gene regulatory network for root hair development.

Shibata, Michitaro and Sugimoto, Keiko

RIKEN Center for Sustainable Resource Science, 230-0045, Yokohama, Japan. michitaro.shibata@riken.jp.; RIKEN Center for Sustainable Resource Science, 230-0045, Yokohama, Japan.

Root hairs play important roles for the acquisition of nutrients, microbe interaction and plant anchorage. In addition, root hairs provide an excellent model system to study cell patterning, differentiation and growth. Arabidopsis root hairs have been thoroughly studied to understand how plants regulate cell fate and growth in response to environmental signals. Accumulating evidence suggests that a multi-layered gene regulatory network is the molecular secret to enable the flexible and adequate response to multiple signals. In this review, we describe the key transcriptional regulators controlling cell fate and/or cell growth of root hairs. We also discuss how plants integrate phytohormonal and environmental signals, such as auxin, ethylene and phosphate availability, and modulate the level of these transcriptional regulators to tune root hair development.

PMID: 30903397

J AOAC Int , IF:1.51 , 2019 May , V102 (3) : P748-760 doi: 10.5740/jaoacint.18-0310

Comparative Analysis of Soluble Proteins in Four Medicinal Aloe Species by Two-Dimensional Electrophoresis and MALDI-TOF-MS.

Fan, Jiao-Jiao and Li, Chun-Hong and Hu, Guang and Tan, Cheng-Ning and Yang, Feng-Qing and Chen, Hua and Xia, Zhi-Ning

Chongqing University, School of Chemistry and Chemical Engineering, 174 Shazheng St, Chongqing 400031, China.; Sunshine Lake Pharma Co., Ltd, Dongguan, 1 Gongye N Rd, Guangdong 523850, China.; Chongqing University of Technology, College of Pharmacy and Bioengineering, 69 Hongguang Ave, Chongqing 400054, China.

Background: Aloe barbadensis Miller 1768, A. vera L. var. chinensis (Haw.) Berger 1908, A. ferox Miller 1768, and A. arborescens Miller 1768 are the most widely cultivated species of Aloe and are used in Asia along with 400 other Aloe species worldwide because of their potent and potential bioactivity. Objective: The objective was to analyze and compare the soluble proteins of four commonly used medicinal Aloe species. Methods: Aloe protein samples were obtained by TCA/acetone-saturated phenol-methanol/ammonium acetate combined extraction (phenol extraction), and then were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis. Finally, the differentially expressed proteins of four Aloe species were identified by matrix-assisted laser desorption ionization-time-of-flight-MS analysis. Results: The phenol extraction method was the most suitable method for the protein extraction of Aloe. Fifty differentially expressed proteins in four Aloe species were successfully identified and divided into eight functional categories. Furthermore, Malate dehydrogenase and ran-binding protein in A. barbadensis, cytoskeletal-related protein tubulin in A. vera var. chinensis and auxin-induced protein PCNT-115 in A. arborescens are closely related to their morphological characteristics. Conclusions: There are differences in the soluble proteins of the four Aloe species. Those proteins, related to the difference of their morphology of Aloe, might be used to identify different species. Highlights: Fifty differentially expressed proteins in four medicinal Aloe species were identified, and these proteins were classified into eight categories according to their biological functions. Four special proteins closely related to the morphological characteristics of Aloe were found and might be used to identify these four Aloe species.

PMID: 30388972

J Pestic Sci , IF:1.101 , 2019 May , V44 (2) : P136-140 doi: 10.1584/jpestics.D19-005

Physiological disorder of plants depending on clopyralid concentration in the soil and plant.

Namiki, Sayuri and Seike, Nobuyasu and Watanabe, Eiki

Institute for Agro-Environmental Sciences, NARO.

The influence of clopyralid in soil on plant growth was investigated over time using three plants. The order of clopyralid sensitivity was as follows: Solanum lycopersicum>Solanum melongena>Momordica charantia, especially physiological disorder of S. lycopersicum were rapidly expressed as various serious symptoms with increasing concentration of clopyralid. In contrast, the clopyralid concentration of above-ground part was in the following order: M. charantia>S. lycopersicum, S. melongena, which differed from the order of sensitivity to clopyralid.

PMID: 31148940