Plant Biotechnol J , IF:8.154 , 2020 Jan doi: 10.1111/pbi.13351
The high-quality genome of diploid strawberry (Fragaria nilgerrensis) provides new insights into anthocyanin accumulation.
Liaoning Key Laboratory of Strawberry Breeding and Cultivation, College of Horticulture, Shenyang Agricultural University, Shenyang, China.; Biomarker Technologies Corporation, Beijing, China.
Fragaria nilgerrensis is a wild diploid strawberry species endemic to east and southeast region in Asia and provides a rich source of genetic variations for strawberry improvement. Here, we present a chromosome-scale assembly of F. nilgerrensis using single-molecule real-time (SMRT) Pacific Biosciences sequencing and chromosome conformation capture (Hi-C) genome scaffolding. The genome assembly size was 270.3 Mb, with a contig N50 of approximately 8.5 Mb. A total of 28 780 genes and 117.2 Mb of transposable elements were annotated for this genome. Next, detailed comparative genomics with the high-quality F. vesca reference genome was conducted to obtain the difference among transposable elements, SNPs, Indels, and so on. The genome size of F. nilgerrensis was enhanced by around 50 Mb relatively to F. vesca, which is mainly due to expansion of transposable elements. In comparison with the F. vesca genome, we identified 4 561 825 SNPs, 846 301 Indels, 4243 inversions, 35 498 translocations and 10 099 relocations. We also found a marked expansion of genes involved in phenylpropanoid biosynthesis, starch and sucrose metabolism, cyanoamino acid metabolism, plant-pathogen interaction, brassinosteroid biosynthesis and plant hormone signal transduction in F. nilgerrensis, which may account for its specific phenotypes and considerable environmental adaptability. Interestingly, we found sequence variations in the upstream regulatory region of FnMYB10, a core transcriptional activator of anthocyanin biosynthesis, resulted in the low expression level of the FnMYB10 gene, which is likely responsible for white fruit phenotype of F. nilgerrensis. The high-quality F. nilgerrensis genome will be a valuable resource for biological research and comparative genomics research.
PMID: 32003918
Plant Physiol , IF:6.902 , 2020 Jan , V182 (1) : P669-678 doi: 10.1104/pp.19.00448
A Mutant Allele Uncouples the Brassinosteroid-Dependent and Independent Functions of BRASSINOSTEROID INSENSITIVE 1.
Department of Cell Biology, Centre for Organismal Studies Heidelberg, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.; Plant Physiology, Center for Plant Molecular Biology, Universitat Tubingen, Auf der Morgenstelle 32, 72076 Tubingen, Germany.; Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universite Paris-Saclay, 78000 Versailles, France.; Department of Cell Biology, Centre for Organismal Studies Heidelberg, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany sebastian.wolf@cos.uni-heidelberg.de.
Plants depend on various cell surface receptors to integrate extracellular signals with developmental programs. One of the best-studied receptors is BRASSINOSTEROID INSENSITIVE 1 (BRI1) in Arabidopsis (Arabidopsis thaliana). Upon binding of its hormone ligands, BRI1 forms a complex with a shape-complementary coreceptor and initiates a signal transduction cascade, which leads to a variety of responses. At the macroscopic level, brassinosteroid (BR) biosynthetic and receptor mutants have similar growth defects, which initially led to the assumption that the signaling pathways were largely linear. However, recent evidence suggests that BR signaling is interconnected with several other pathways through various mechanisms. We recently described that feedback from the cell wall is integrated at the level of the receptor complex through interaction with RECEPTOR-LIKE PROTEIN 44 (RLP44). Moreover, BRI1 is required for another function of RLP44: the control of procambial cell fate. Here, we report a BRI1 mutant, bri1 (cnu4) , which differentially affects canonical BR signaling and RLP44 function in the vasculature. Although BR signaling is only mildly impaired, bri1 (cnu4) mutants show ectopic xylem in place of procambium. Mechanistically, this is explained by an increased association between RLP44 and the mutated BRI1 protein, which prevents the former from acting in vascular cell fate maintenance. Consistent with this, the mild BR response phenotype of bri1 (cnu4) is a recessive trait, whereas the RLP44-mediated xylem phenotype is semidominant. Our results highlight the complexity of plant plasma membrane receptor function and provide a tool to dissect BR signaling-related roles of BRI1 from its noncanonical functions.
PMID: 31641077
Plant Physiol , IF:6.902 , 2020 Jan , V182 (1) : P185-203 doi: 10.1104/pp.19.00416
PcG Proteins MSI1 and BMI1 Function Upstream of miR156 to Regulate Aerial Tuber Formation in Potato.
Biology Division, Indian Institute of Science Education and Research, Pune 411008, Maharashtra, India.; Biology Division, Indian Institute of Science Education and Research, Pune 411008, Maharashtra, India akb@iiserpune.ac.in.
Polycomb Repressive Complexes (PRC1 and PRC2) regulate developmental transitions in plants. AtBMI1, a PRC1 member, represses micro RNA156 (miR156) to trigger the onset of adult phase in Arabidopsis (Arabidopsis thaliana). miR156 overexpression (OE) reduces below-ground tuber yield, but stimulates aerial tubers in potato (Solanum tuberosum ssp andigena) under short-day (SD) photoperiodic conditions. Whether PRC members could govern tuber development through photoperiod-mediated regulation of miR156 is unknown. Here, we investigated the role of two PRC proteins, StMSI1 (PRC2 member) and StBMI1-1, in potato development. In wild-type andigena plants, StMSI1 and miR156 levels increased in stolon, whereas StBMI1-1 decreased under SD conditions. StMSI1-OE and StBMI1-1-antisense (AS) lines produced pleiotropic effects, including altered leaf architecture/compounding and reduced below-ground tuber yield. Notably, these lines showed enhanced miR156 accumulation accompanied by aerial stolons and tubers from axillary nodes, similar to miR156-OE lines. Further, grafting of StMSI1-OE or StBMI1-1-AS on wild-type stock resulted in reduced root biomass and showed increased accumulation of miR156a/b and -c precursors in the roots of wild-type stocks. RNA-sequencing of axillary nodes from StMSI1-OE and StBMI1-1-AS lines revealed downregulation of auxin and brassinosteroid genes, and upregulation of cytokinin transport/signaling genes, from 1,023 differentially expressed genes shared between the two lines. Moreover, we observed downregulation of genes encoding H2A-ubiquitin ligase and StBMI1-1/3, and upregulation of Trithorax group H3K4-methyl-transferases in StMSI1-OE Chromatin immunoprecipitation-quantitative PCR confirmed H3K27me3-mediated suppression of StBMI1-1/3, and H3K4me3-mediated activation of miR156 in StMSI1-OE plants. In summary, we show that cross talk between histone modifiers regulates miR156 and alters hormonal response during aerial tuber formation in potato under SD conditions.
PMID: 31427464
J Exp Bot , IF:5.908 , 2020 Jan , V71 (3) : P970-985 doi: 10.1093/jxb/erz468
CIRCADIAN CLOCK ASSOCIATED 1 and ATAF2 differentially suppress cytochrome P450-mediated brassinosteroid inactivation.
Department of Crop and Soil Sciences, Washington State University, Pullman, WA, USA.
Brassinosteroids (BRs) are a group of steroid hormones regulating plant growth and development. Since BRs do not undergo transport among plant tissues, their metabolism is tightly regulated by transcription factors (TFs) and feedback loops. BAS1 (CYP734A1, formerly CYP72B1) and SOB7 (CYP72C1) are two BR-inactivating cytochrome P450s identified in Arabidopsis thaliana. We previously found that a TF ATAF2 (ANAC081) suppresses BAS1 and SOB7 expression by binding to the Evening Element (EE) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1)-binding site (CBS) on their promoters. Both the EE and CBS are known binding targets of the circadian regulatory protein CCA1. Here, we confirm that CCA1 binds the EE and CBS motifs on BAS1 and SOB7 promoters, respectively. Elevated accumulations of BAS1 and SOB7 transcripts in the CCA1 null mutant cca1-1 indicate that CCA1 is a repressor of their expression. When compared with either cca1-1 or the ATAF2 null mutant ataf2-2, the cca1-1 ataf2-2 double mutant shows higher SOB7 transcript accumulations and a stronger BR-insensitive phenotype of hypocotyl elongation in white light. CCA1 interacts with ATAF2 at both DNA-protein and protein-protein levels. ATAF2, BAS1, and SOB7 are all circadian regulated with distinct expression patterns. These results demonstrate that CCA1 and ATAF2 differentially suppress BAS1- and SOB7-mediated BR inactivation.
PMID: 31639820
Int J Mol Sci , IF:4.556 , 2020 Jan , V21 (3) doi: 10.3390/ijms21030872
Roles of Brassinosteroids in Plant Reproduction.
Key Laboratory of Plant Development and Environmental Adaption Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China.; National Key Laboratory of Plant Molecular Genetics & Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China.
Brassinosteroids (BRs) are a group of steroid hormones, essentially important for plant development and growth. BR signaling functions to promote cell expansion and cell division, and plays a role in etiolation and reproduction. As the phytohormone originally identified in the pollen grains of Brassica napus, BR promotes the elongation of stigma. Recent studies have revealed that BR is also critical for floral transition, inflorescence stem architecture formation and other aspects of plant reproductive processes. In this review, we focus on the current understanding of BRs in plant reproduction, the spatial and temporal control of BR signaling, and the downstream molecular mechanisms in both the model plant Arabidopsis and crops. The crosstalk of BR with environmental factors and other hormones in reproduction will also be discussed.
PMID: 32013254
Int J Mol Sci , IF:4.556 , 2020 Jan , V21 (3) doi: 10.3390/ijms21030848
Transcriptome Analysis of Rice Roots in Response to Root-Knot Nematode Infection.
College of Plant Protection, Nematology Institute of Northern China, Shenyang Agricultural University, Shenyang 110866, China.; Shaanxi Key Laboratory of Chinese Jujube, College of Life Science, Yan'an University, Yan'an, Shaanxi 716000, China.
Meloidogyne incognita and Meloidogyne graminicola are root-knot nematodes (RKNs) infecting rice (Oryza sativa L.) roots and severely decreasing yield, whose mechanisms of action remain unclear. We investigated RKN invasion and development in rice roots through RNA-seq transcriptome analysis. The results showed that 952 and 647 genes were differently expressed after 6 (invasion stage) and 18 (development stage) days post inoculation, respectively. Gene annotation showed that the differentially expressed genes were classified into diverse metabolic and stress response categories. Furthermore, phytohormone, transcription factor, redox signaling, and defense response pathways were enriched upon RKN infection. RNA-seq validation using qRT-PCR confirmed that CBL-interacting protein kinase (CIPK) genes (CIPK5, 8, 9, 11, 14, 23, 24, and 31) as well as brassinosteroid (BR)-related genes (OsBAK1, OsBRI1, D2, and D11) were altered by RKN infection. Analysis of the CIPK9 mutant and overexpressor indicated that the RKN populations were smaller in cipk9 and larger in CIPK9 OX, while more galls were produced in CIPK9 OX plant roots than the in wild-type roots. Significantly fewer numbers of second-stage infective juveniles (J2s) were observed in the plants expressing the BR biosynthesis gene D2 mutant and the BR receptor BRI1 activation-tagged mutant (bri1-D), and fewer galls were observed in bri1-D roots than in wild-type roots. The roots of plants expressing the regulator of ethylene signaling ERS1 (ethylene response sensor 1) mutant contained higher numbers of J2s and developed more galls compared with wild-type roots, suggesting that these signals function in RKN invasion or development. Our findings broaden our understanding of rice responses to RKN invasion and provide useful information for further research on RKN defense mechanisms.
PMID: 32013011
Int J Mol Sci , IF:4.556 , 2020 Jan , V21 (1) doi: 10.3390/ijms21010354
Exploring the Brassinosteroid Signaling in Monocots Reveals Novel Components of the Pathway and Implications for Plant Breeding.
Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, Jagiellonska 28, 40-032 Katowice, Poland.
Brassinosteroids (BRs) are a class of steroidal phytohormones which are key regulators of diverse processes during whole life cycle of plants. Studies conducted in the dicot model species Arabidopsis thaliana have allowed identification and characterization of various components of the BR signaling. It is currently known that the BR signaling is interconnected at various stages with other phytohormonal and stress signaling pathways. It enables a rapid and efficient adaptation of plant metabolism to constantly changing environmental conditions. However, our knowledge about mechanism of the BR signaling in the monocot species is rather limited. Thus, identification of new components of the BR signaling in monocots, including cereals, is an ongoing process and has already led to identification of some monocot-specific components of the BR signaling. It is of great importance as disturbances in the BR signaling influence architecture of mutant plants, and as a consequence, the reaction to environmental conditions. Currently, the modulation of the BR signaling is considered as a target to enhance yield and stress tolerance in cereals, which is of particular importance in the face of global climate change.
PMID: 31948086
Int J Mol Sci , IF:4.556 , 2020 Jan , V21 (2) doi: 10.3390/ijms21020426
Dynamic Transcriptome Analysis Reveals Uncharacterized Complex Regulatory Pathway Underlying Dose IBA-Induced Embryogenic Redifferentiation in Cotton.
State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an 271018, China.; College of Life Sciences, Huaibei Normal University, Huaibei 235000, China.
The somatic embryogenesis (SE) process of plants is regulated by exogenous hormones. During the SE, different genes sensitively respond to hormone signals through complex regulatory networks to exhibit plant totipotency. When cultured in indole-3-butyric acid (IBA) concentration gradient medium supplemented with 0 mg dm(-3), 0.025 mg dm(-3), and 0.05 mg dm(-3) IBA, the callus differentiation rate first increased then decreased in cotton. To characterize the molecular basis of IBA-induced regulating SE, transcriptome analysis was conducted on embryogenic redifferentiation. Upon the examination of the IBA's embryogenic inductive effect, it was revealed that pathways related to plant hormone signal transduction and alcohol degradation were significantly enriched in the embryogenic responsive stage (5 days). The photosynthesis, alcohol metabolism and cell cycle pathways were specifically regulated in the pre-embryonic initial period (20 days). Upon the effect of the IBA dose, in the embryogenic responsive stage (5 days), the metabolism of xenobiotics by the cytochrome P450 pathway and secondary metabolism pathways of steroid, flavonoid, and anthocyanin biosynthesis were significantly enriched. The phenylpropanoid, brassinosteroid, and anthocyanin biosynthesis pathways were specifically associated in the pre-embryonic initial period (20 days). At different developmental stages of embryogenic induction, photosynthesis, flavonoid biosynthesis, phenylpropanoid biosynthesis, mitogen-activated protein kinase (MAPK) signaling, xenobiotics metabolism by cytochrome P450, and brassinosteroid biosynthesis pathways were enriched at low a IBA concentration. Meanwhile, at high IBA concentration, the carbon metabolism, alcohol degradation, circadian rhythm and biosynthesis of amino acids pathways were significantly enriched. The results reveal that complex regulating pathways participate in the process of IBA-induced redifferentiation in cotton somatic embryogenesis. In addition, collections of potential essential signaling and regulatory genes responsible for dose IBA-induced efficient embryogenic redifferentiation were identified. Quantitative real-time PCR (qRT-PCR) was performed on the candidate genes with different expression patterns, and the results are basically consistent with the RNA-seq data. The results suggest that the complicated and concerted IBA-induced mechanisms involving multiple cellular pathways are responsible for dose-dependent plant growth regulator-induced SE. This report represents a systematic study and provides new insight into molecular signaling and regulatory basis underlying the process of dose IBA-induced embryogenic redifferentiation during SE.
PMID: 31936561
J Agric Food Chem , IF:4.192 , 2020 Jan , V68 (3) : P703-711 doi: 10.1021/acs.jafc.9b06491
Molecular Mechanism Underlying the Effect of the Intraspecific Alternation of Seed Size on Plant Drought Tolerance.
Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province , Jiangsu Normal University , Xuzhou , Jiangsu 221116 , People's Republic of China.; State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology , Lanzhou University , Lanzhou , Gansu 730020 , People's Republic of China.
In crop plants, the yield loss caused by drought exceeds the losses resulting from other adverse environment stresses. In numerous plant species, seedling establishment is positively correlated with the initial seed size under drought stress conditions. In intra- and interspecies, plants with large seeds can withstand water deficiency stresses, whereas those with small seeds are efficient colonizers as a result of their ability to produce more seeds. Therefore, larger initial seeds confer more drought resistance on germinating seedlings. Although this phenomenon has been observed by evolutionary biologists and ecologists, the correlation of initial seed size with the drought resistance of seedlings/plants is not well-reviewed and characterized. Furthermore, the related molecular mechanisms are unknown. Understanding these mechanisms will benefit future breeding or design strategies to increase crop yields. In the present review, we focus on recent research to analyze the genetic factors of plants/crops involved in the regulation of seed size and drought tolerance and their corresponding signal transduction pathways. Several signaling pathways that determine plant drought tolerance through influencing the initial seed size are identified. Such pathways include those that are involved in mitogen-activated protein kinase, abscisic acid, brassinosteroids, and several transcription factors and sugar signaling pathways.
PMID: 31904950
Sci Rep , IF:3.998 , 2020 Jan , V10 (1) : P897 doi: 10.1038/s41598-020-57717-0
Transcriptional trajectories of anther development provide candidates for engineering male fertility in sorghum.
Crop Genetics & Informatics Group, School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.; Division of Plant Physiology, Indian Agricultural Research Institute, Pusa, New Delhi, 110012, India.; Crop Genetics & Informatics Group, School of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.; Crop Genetics & Informatics Group, School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India. rita.genomics@gmail.com.
Sorghum is a self-pollinated crop with multiple economic uses as cereal, forage, and biofuel feedstock. Hybrid breeding is a cornerstone for sorghum improvement strategies that currently relies on cytoplasmic male sterile lines. To engineer genic male sterility, it is imperative to examine the genetic components regulating anther/pollen development in sorghum. To this end, we have performed transcriptomic analysis from three temporal stages of developing anthers that correspond to meiotic, microspore and mature pollen stages. A total of 5286 genes were differentially regulated among the three anther stages with 890 of them exhibiting anther-preferential expression. Differentially expressed genes could be clubbed into seven distinct developmental trajectories using K-means clustering. Pathway mapping revealed that genes involved in cell cycle, DNA repair, regulation of transcription, brassinosteroid and auxin biosynthesis/signalling exhibit peak expression in meiotic anthers, while those regulating abiotic stress, carbohydrate metabolism, and transport were enriched in microspore stage. Conversely, genes associated with protein degradation, post-translational modifications, cell wall biosynthesis/modifications, abscisic acid, ethylene, cytokinin and jasmonic acid biosynthesis/signalling were highly expressed in mature pollen stage. High concurrence in transcriptional dynamics and cis-regulatory elements of differentially expressed genes in rice and sorghum confirmed conserved developmental pathways regulating anther development across species. Comprehensive literature survey in conjunction with orthology analysis and anther-preferential accumulation enabled shortlisting of 21 prospective candidates for in-depth characterization and engineering male fertility in sorghum.
PMID: 31964983
Plant Cell Rep , IF:3.825 , 2020 Jan , V39 (1) : P35-46 doi: 10.1007/s00299-019-02471-5
Banana MaBZR1/2 associate with MaMPK14 to modulate cell wall modifying genes during fruit ripening.
Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation, Ministry of Education, College of Horticulture, South China Agricultural University, Guangzhou, 510642, People's Republic of China.; Hainan Key Laboratory of Banana Genetic Improvement, Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, 570102, People's Republic of China.; Guangdong Food and Drug Vocational College, Longdongbei Road 321, Tianhe District, Guangzhou, 510520, People's Republic of China. suxg@gdyzy.edu.cn.; Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation, Ministry of Education, College of Horticulture, South China Agricultural University, Guangzhou, 510642, People's Republic of China. jfkuang@scau.edu.cn.
KEY MESSAGE: Banana MaBZR1/2 interact with MaMPK14 to enhance the transcriptional inhibition of cell wall modifying genes including MaEXP2, MaPL2 and MaXET5. Fruit ripening and softening, the major attributes to perishability in fleshy fruits, are modulated by various plant hormones and gene expression. Banana MaBZR1/2, the central transcription factors of brassinosteroid (BR) signaling, mediate fruit ripening through regulation of ethylene biosynthesis, but their possible roles in fruit softening as well as the underlying mechanisms remain to be determined. In this work, we found that MaBZR1/2 directly bound to and repressed the promoters of several cell wall modifying genes such as MaEXP2, MaPL2 and MaXET5, whose transcripts were elevated concomitant with fruit ripening. Moreover, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays indicated that MaBZR1/2 physically interacted with a mitogen-activated protein kinase MaMPK14, and this interaction strengthened the MaBZR1/2-mediated transcriptional inhibitory abilities. Collectively, our study provides insight into the mechanism of MaBZR1/2 contributing to fruit ripening and softening, which may have potential for banana molecular improvement.
PMID: 31501956
Planta , IF:3.39 , 2020 Jan , V251 (2) : P43 doi: 10.1007/s00425-019-03335-8
Systematic identification of genes associated with plant growth-defense tradeoffs under JA signaling in Arabidopsis.
State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, No. 94 Weijin Road, Tianjin, 300071, People's Republic of China.; State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, No. 94 Weijin Road, Tianjin, 300071, People's Republic of China. fanzj@nankai.edu.cn.
MAIN CONCLUSION: Co-expression and regulatory networks yield important insights into the growth-defense tradeoffs mechanism under jasmonic acid (JA) signals in Arabidopsis. Elevated defense is commonly associated with growth inhibition. However, a comprehensive atlas of the genes associated with the plant growth-defense tradeoffs under JA signaling is lacking. To gain an insight into the dynamic architecture of growth-defense tradeoffs, a coexpression network analysis was employed on publicly available high-resolution transcriptomes of Arabidopsis treated with coronatine (COR), a mimic of jasmonoyl-l-isoleucine. The genes involved in JA-mediated growth-defense tradeoffs were systematically revealed. Promoter enrichment analysis revealed the core regulatory module in which the genes underwent rapid activation, sustained upregulation after COR treatment, and mediated the growth-defense tradeoffs. Several transcription factors (TFs), including RAP2.6L, MYB44, WRKY40, and WRKY18, were identified as instantly activated components associated with pathogen and insect resistance. JA might rapidly activate RAV1 and KAN1 to repress brassinosteroid (BR) response genes, upregulate KAN1, the C2H2 TF families ZF2, ZF3, ZAT6, and STZ/ZAT10 to repress the biosynthesis, transport, and signaling of auxin to arrest growth. Independent datasets and preserved analyses validated the reproducibility of the results. Our study provided a comprehensive snapshot of genes that respond to JA signals and provided valuable resources for functional studies on the genetic modification of breeding population that exhibit robust growth and defense simultaneously.
PMID: 31907627
Photosynth Res , IF:3.216 , 2020 Jan doi: 10.1007/s11120-020-00708-z
24-Epibrassinolide alleviates the toxic effects of NaCl on photosynthetic processes in potato plants.
National Research Tomsk State University, Tomsk, Russian Federation.; K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russian Federation. ilya.zlobin.90@mail.ru.; K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russian Federation.; Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russian Federation.; Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Belarus, Belarus.; K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russian Federation. suleyman.allakhverdiev@gmail.com.; Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russian Federation. suleyman.allakhverdiev@gmail.com.; M.V. Lomonosov Moscow State University, Moscow, Russia. suleyman.allakhverdiev@gmail.com.; College of Science, King Saud University, Riyadh, Saudi Arabia. suleyman.allakhverdiev@gmail.com.; Institute of Molecular Biology and Biotechnology, ANAS, Baku, Azerbaijan. suleyman.allakhverdiev@gmail.com.; Moscow Institute of Physics and Technology, Dolgoprudny, Moscow, Russian Federation. suleyman.allakhverdiev@gmail.com.
Brassinosteroids are promising agents for alleviating the negative effects of salinity on plants, but the mechanism of their protective action is far from being understood. We investigated the effect of pretreatment with 24-epibrassinolide (24-EBL) on the photosynthetic and physiological parameters of potato plants under progressive salinity stress caused by root application of 100 mM NaCl. Salinity clearly inhibited primary photosynthetic processes in potato plants by reducing the contents of photosynthetic pigments, photosynthetic electron transport and photosystem II (PSII) maximal and effective quantum yields. These negative effects of salinity on primary photosynthetic processes were mainly due to toxic ionic effects on the plant's ability to oxidize the plastoquinone pool. Pretreatment with 24-EBL alleviated this stress effect and allowed the maintenance of plastoquinone pool oxidation and the efficiency of photosystem II photochemistry to be at the same levels as those in unstressed plants; however, the pretreatment did not affect the photosynthetic pigment content. 24-EBL pretreatment clearly alleviated the decrease in leaf osmotic potential under salinity stress. The stress-induced increases in lipid peroxidation and proline contents were not changed under brassinosteroid pretreatment. However, 24-EBL pretreatment increased the peroxidase activity and improved the K(+)/Na(+) ratio in potato leaves, which were likely responsible for the protective 24-EBL action under salt stress.
PMID: 31939071
J Plant Physiol , IF:3.013 , 2020 Jan , V244 : P153090 doi: 10.1016/j.jplph.2019.153090
Plasma membrane ATPase and the aquaporin HvPIP1 in barley brassinosteroid mutants acclimated to high and low temperature.
Polish Academy of Sciences, The Franciszek Gorski Institute of Plant Physiology, Niezapominajek 21, 30-239 Krakow, Poland. Electronic address: i.sadura@ifr-pan.edu.pl.; Polish Academy of Sciences, The Franciszek Gorski Institute of Plant Physiology, Niezapominajek 21, 30-239 Krakow, Poland.; University of Agriculture in Krakow, Department of Plant Physiology, Podluzna 3, 30-239 Krakow, Poland.; University of Silesia, Faculty of Biology and Environment Protection, Department of Genetics, Jagiellonska 28, 40-032 Katowice, Poland.
The integral parts of the cell membranes are the functional proteins, which are crucial for cell life. Among them, proton-pumping ATPase and aquaporins appear to be of particular importance. There is some knowledge about the effect of the temperature during plant growth, including stress-inducing temperatures, on the accumulation of the membrane proteins: plasma membrane H(+)-ATPase and aquaporins, but not much is known about the effect of the phytohormones (i.e. brassinosteroids (BR)) on control of accumulation of these proteins. The aim of our study was to answer the question of how a BR deficit and disturbances in the BR perception/signalling affect the accumulation of plasma membrane H(+)-ATPase (PM H(+)-ATPase), the aquaporin HvPIP1 transcript and protein in barley growing at 20 degrees C and during its acclimation at 5 degrees C and 27 degrees C. For the studies, the BR-deficient mutant 522DK (derived from the wild-type Delisa), the BR-deficient mutant BW084 and the BR-signalling mutant BW312 and their wild-type Bowman were used. Generally, temperature of growth was significant factor influencing on the level of the accumulation of the H(+)-ATPase and HvPIP1 transcript and the PM H(+)-ATPase and HvPIP1 protein in barley leaves. The level of the accumulation of the HvPIP1 transcript decreased at 5 degrees C (compared to 20 degrees C), but was higher at 27 degrees C than at 20 degrees C in the analyzed cultivars. In both cultivars the protein HvPIP1 was accumulated in the highest amounts at 27 degrees C. On the other hand, the barley mutants with a BR deficiency or with BR signalling disturbances were characterised by an altered accumulation level of PM H(+)-ATPase, the aquaporin HvPIP1 transcript and protein (compared to the wild types), which may suggest the involvement of brassinosteroids in regulating PM H(+)-ATPase and aquaporin HvPIP1 at the transcriptional and translational levels.
PMID: 31841952
J Phys Chem B , IF:2.857 , 2020 Jan , V124 (2) : P355-365 doi: 10.1021/acs.jpcb.9b09377
Molecular Mechanism of Brassinosteroid Perception by the Plant Growth Receptor BRI1.
Department of Food Technology and Biochemical Engineering , Jadavpur University , Kolkata , West Bengal 700032 , India.; National Center for Supercomputing Applications , Urbana , Illinois 61801 , United States.
Brassinosteroids (BRs) are essential phytohormones, which bind to the plant receptor, BRI1, to regulate various physiological processes. The molecular mechanism of the perception of BRs by the ectodomain of BRI1 remains not fully understood. It also remains elusive why a substantial difference in biological activity exists between the BRs. In this work, we study the binding mechanisms of the two most bioactive BRs, brassinolide (BLD) and castasterone (CAT), using molecular dynamics simulations. We report free-energy landscapes of the binding processes of both ligands, as well as detailed ligand binding pathways. Our results suggest that CAT has a lower binding affinity compared to BLD due to its inability to form hydrogen-bonding interactions with a tyrosine residue in the island domain of BRI1. We uncover a conserved nonproductive binding state for both BLD and CAT, which is more stable for CAT and may further contribute to the bioactivity difference. Finally, we validate past observations about the conformational restructuring and ordering of the island domain upon BLD binding. Overall, this study provides new insights into the fundamental mechanism of the perception of the two most bioactive BRs, which may create new avenues for genetic and agrochemical control of their signaling cascade.
PMID: 31873025
Plant Biol (Stuttg) , IF:2.167 , 2020 Jan , V22 (1) : P129-133 doi: 10.1111/plb.13040
Active BR signalling adjusts the subcellular localisation of BES1/HSP90 complex formation.
Laboratory of Molecular Biology, Agricultural University of Athens, Athens, Greece.; Department of Cell Biology Centre of the Region Hana for Biotechnological and Agricultural Research, Palacky University Olomouc, Slechtitelu 27, Olomouc, 783 71, Czech Republic.
Heat shock proteins 90 (HSP90) are essential and play critical roles in the adaptation of organisms to diverse stimuli. In plants, HSP90 are involved in auxin, jasmonate and brassinosteroid (BR) signalling pathways. The BR-promoted activation of the BES1 transcription factor regulates BR-responsive genes. Using genetic, physiological, fluorescence live cell imaging, molecular and biochemical approaches, such as phenotypic analysis, co-immunoprecipitation assay, yeast-two hybrid and Bimolecular fluorescence complementation (BiFC), we studied complex formation between BES1 and HSP90 under control conditions and active BR signalling. Further, we determined the effect of the pharmacological inhibition of HSP90 ATPase activity on hypocotyl elongation of bes1-D mutant. We determined that HSP90 interact with BES1 in the nucleus and in the cytoplasm. During active BR signalling, nuclear complexes were absent while cytoplasmic HSP90/BES1 complexes were prominent. Our results showed that the hypocotyl length of bes1-D mutants was highly reduced when HSP90 was challenged by the geldanamycin (GDA) inhibitor of the ATPase activity of HSP90. Active BR signalling could not rescue the GDA effect on the hypocotyl elongation of bes1-D. Our results reveal that the constitutively active BES1 in the bes1-D mutant is hypersensitive to GDA. The interaction of HSP90 with BES1 argues that HSP90 facilitate the nuclear metastable conformation of BES1 to regulate BR-dependent gene expression, and our data show that HSP90 assist in the compartmentalised cycle of BES1 during active BR signalling.
PMID: 31469500