Plant Biotechnol J , IF:8.154 , 2020 Oct doi: 10.1111/pbi.13496
Overexpression of GmMYB14 improves high-density yield and drought tolerance through regulating plant architecture mediated by the brassinosteroid pathway.
Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China.; The industrial crop institute, Shanxi Academy of Agricultural Sciences, Taiyuan, 030031, China.; Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, 79409, USA.; Stress Adaptation Research Unit, RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro-cho, Tsurumi, Yokohama, 230-0045, Japan.
MYB transcription factors (TFs) have been reported to regulate the biosynthesis of secondary metabolites, as well as to mediate plant adaption to abiotic stresses, including drought. However, the roles of MYB TFs in regulating plant architecture and yield potential remain poorly understood. Here, we studied the roles of the dehydration-inducible GmMYB14 gene in regulating plant architecture, high-density yield and drought tolerance through the brassinosteroid (BR) pathway in soybean. GmMYB14 was shown to localize to nucleus and have a transactivation activity. Stable GmMYB14-overexpressing (GmMYB14-OX) transgenic soybean plants displayed a semi-dwarfism and compact plant architecture associated with decreased cell size, resulting in a decrease in plant height, internode length, leaf area, leaf petiole length and leaf petiole angle, and improved yield in high density under field conditions. Results of the transcriptome sequencing suggested the involvement of BRs in regulating GmMYB14-OX plant architecture. Indeed, GmMYB14-OX plants showed reduced endogenous BR contents, while exogenous application of brassinolide could partly rescue the phenotype of GmMYB14-OX plants. Furthermore, GmMYB14 was shown to directly bind to the promoter of GmBEN1 and up-regulate its expression, leading to reduced BR content in GmMYB14-OX plants. GmMYB14-OX plants also displayed improved drought tolerance under field conditions. GmBEN1 expression was also up-regulated in the leaves of GmMYB14-OX plants under polyethylene glycol treatment, indicating that the GmBEN1-mediated reduction of BR level under stress also contributed to drought/osmotic stress tolerance of the transgenic plants. Our findings provided a strategy for stably increasing high-density yield and drought tolerance in soybean using a single TF-encoding gene.
PMID: 33098207
Plant Physiol , IF:6.902 , 2020 Oct doi: 10.1104/pp.20.00632
Towards "smart canopy" sorghum: discovery of the genetic control of leaf angle across layers.
Bayer CITY: St Louis STATE: MO United States Of America [US].; Iowa State University CITY: Ames STATE: IA United States Of America [US].; Iowa State Univerisity CITY: Ames STATE: IA United States Of America [US].; Iowa State University 2035B Carver Co-Laboratory CITY: Ames STATE: Iowa POSTAL_CODE: 50011-3650 United States Of America [US].; Iowa State University CITY: Ames STATE: IA POSTAL_CODE: 50011 United States Of America [US] mgsalas@iastate.edu.
A "smart canopy" ideotype has been proposed with leaves being upright at the top and more horizontal towards the bottom of the plant to maximize light interception and conversion efficiencies, and thus increasing yield. The genetic control of leaf angle has to date been studied on one or two leaves, or data have been merged from multiple leaves to generate average values. This approach has limited our understanding of the diversity of leaf angles across layers and their genetic control. Genome wide association studies (GWAS) and quantitative trait loci (QTL) mapping studies in sorghum (Sorghum bicolor) were performed using layer-specific angle data collected manually and via high-throughput phenotyping strategies. The observed distribution of angles in indoor and field settings is opposite to the ideotype. Several genomic regions were associated with leaf angle within layers or across the canopy. The expression of the brassinosteroid-related transcription factor BZR1/BES1 and the auxin-transporter Dw3 were found to be highly correlated with the distribution of angles at different layers. The application of a BR biosynthesis inhibitor could not revert the undesirable overall angle distribution. These discoveries demonstrate that the exploitation of layer-specific QTL/genes will be instrumental to reversing the natural angle distribution in sorghum according to the "smart canopy" ideotype.
PMID: 33093232
Plant Physiol , IF:6.902 , 2020 Oct doi: 10.1104/pp.20.00474
Microtubule-associated protein CLASP is translationally regulated in light-dependent root apical meristem growth.
The University of British Columbia CITY: Vancouver STATE: BC Canada [CA].; The University of British Columbia CITY: Vancouver STATE: BC POSTAL_CODE: V6T 1Z4 Canada [CA] geoffrey.wasteneys@ubc.ca.
The ability for plant growth to be optimized, either in the light or dark, depends on the intricate balance between cell division and differentiation in specialized regions called meristems. When Arabidopsis thaliana seedlings are grown in the dark, hypocotyl elongation is promoted, whereas root growth is greatly reduced as a result of changes in hormone transport and a reduction in meristematic cell proliferation. Previous work showed that the microtubule-associated protein CLASP sustains root apical meristem (RAM) size by influencing microtubule (MT) organization and by modulating the brassinosteroid (BR) signalling pathway. Here, we investigated whether CLASP is involved in light-dependent root growth promotion, since dark-grown seedlings have reduced RAM activity that is observed in the clasp-1 null mutant. We showed that CLASP protein levels were greatly reduced in the root tips of dark-grown seedlings, which could be reversed by exposing plants to light. We confirmed that removing seedlings from the light led to a discernible shift in MT organization from bundled arrays, which are prominent in dividing cells, to transverse orientations typically observed in cells that have exited the meristem. BR receptors and auxin transporters, both of which are sustained by CLASP, were largely degraded in the dark. Interestingly, we found that despite the lack of protein, CLASP transcript levels were higher in dark-grown root tips. Together, these findings uncover a mechanism that sustains meristem homeostasis through CLASP, and advances our understanding of how roots modulate their growth according to the amount of light and nutrients perceived by the plant.
PMID: 33023938
Plant J , IF:6.141 , 2020 Oct doi: 10.1111/tpj.15036
What is going on with the hormonal control of flowering in plants?
Laboratory of Plant Breeding & Genetics, Department of agricultural and environmental biology, The University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo, Japan, 113-8657.
Molecular genetic studies using Arabidopsis thaliana as a model system have overwhelmingly revealed a lot of important molecular mechanisms underlying the control of various biological events, including floral induction in plants. The major genetic pathways of flowering have been characterized in-depth, and include the photoperiod, vernalization, autonomous, and gibberellin (GA) pathways. In recent years, novel flowering pathways are increasingly being identified. These include age-, thermosensory, sugar-, stress-, and hormonal signals to control floral transition. Among them, hormonal control of flowering except the GA pathway is not formally considered as a major flowering pathway per se, due to relatively weak and often pleiotropic genetic effects, complex phenotypic variations, including some controversial ones. However, a number of recent studies have suggested that various stress signals may be mediated by hormonal regulation of flowering. In the view of molecular diversity in plant kingdoms, this review begins with an assessment of photoperiodic flowering, not in A. thaliana, but in rice (Oryza sativa); rice is a staple crop for human consumption worldwide, and is a model system of short-day plants, cereals, and breeding crops. The rice flowering pathway is then compared to that of A. thaliana. This review then aims to update our knowledge on hormonal control of flowering, and integrate it into the entire flowering gene network.
PMID: 33111430
Plant J , IF:6.141 , 2020 Oct doi: 10.1111/tpj.15018
Phytochrome A inhibits shade avoidance responses under strong shade through repressing the brassinosteroid pathway in Arabidopsis.
School of Life Sciences, Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian Province, 361102, China.
In dense canopy, a reduction in red to far-red (R:FR) light ratio triggers shade avoidance responses (SARs) in Arabidopsis thaliana, a shade avoiding plant. Two red/far-red (R/FR) light photoreceptors, PHYB and PHYA, were reported to be key negative regulators of the SARs. PHYB represses the SARs under normal light conditions, however, the role of PHYA in the SARs remain elusive. We set up two shade conditions: Shade and strong Shade (s-Shade) with different R:FR ratios (0.7 and 0.1), which allowed us to observe phenotypes dominated by PHYB- and PHYA-mediated pathway, respectively. By comparing the hypocotyl growth under these two conditions along the time, we found PHYA was predominantly activated in the s-Shade after prolonged shade treatment. We further showed that under the s-Shade, PHYA inhibits hypocotyl elongation partially through repressing the brassinosteroid (BR) pathway. COP1 and PIF4,5 act downstream of PHYA. After prolonged shade treatment, the nuclear localization of COP1 was reduced, while the PIF4 protein level was much lower in the s-Shade than that in Shade. Both changes occurred in a PHYA-dependent manner. We propose that under deep canopy, the R:FR ratio is extremely low, which promotes the nuclear accumulation of PHYA. Activated PHYA reduces COP1 nuclear speckle, which may lead to changes of downstream targets, such as PIF4,5 and HY5. Together, these proteins regulate the BR pathway through modulating BES1/BZR1 and the expression of BR biosynthesis and BR target genes.
PMID: 33037720
J Exp Bot , IF:5.908 , 2020 Oct doi: 10.1093/jxb/eraa495
The conserved brassinosteroid-related transcription factor BIM1a negatively regulates fruit growth in tomato.
INRAE, Univ. Bordeaux, UMR BFP, Villenave d'Ornon, France.; Instituto de Biotecnologia, Instituto Nacional de Tecnologia Agropecuaria, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Castelar, Argentina.; Department of Plant Life Science, Faculty of Agriculture, Ryukoku University, Otsu, Shiga, Japan.; Department of Natural Sciences, International Christian University, Tokyo, Japan.; Faculty of Life and Environmental Sciences, University of Tsukuba, Tskuba, Japan.; Tsukuba Plant Innovation Research Center, University of Tsukuba, Tskuba, Japan.
Brassinosteroids (BRs) are steroid hormones that play key roles in plant development and defense. Our goal is to harness the extensive knowledge of the Arabidopsis BR signalling network for improving productivity in crop species. This first requires identifying components of the conserved network and their function in the target species. Here, we investigated the function of SlBIM1a, the closest tomato homolog of AtBIM1, which is highly expressed in fruit. SlBIM1a overexpressing lines displayed severe plant and fruit dwarfism, and histological characterization of different transgenic lines revealed that SlBIM1a expression negatively correlated with fruit pericarp cell size, resulting in fruit size modifications. These growth phenotypes were in contrast to those found in Arabidopsis, and this was confirmed by the reciprocal ectopic expression of SlBIM1a/b in Arabidopsis and, AtBIM1 in tomato. These results determined that BIM1 function depends more on the recipient species than on its primary sequence. Yeast two-hybrid interaction studies and transcriptomic analyses of SlBIM1a overexpressing fruit, further suggested that SlBIM1a acts through its interaction with SlBZH1 to govern the transcriptional regulation of growth-related BRs target genes. Together, these results suggest that SlBIM1a is a negative regulator of pericarp cell expansion, possibly at the crossroad with auxin and light signalling.
PMID: 33097930
Int J Mol Sci , IF:4.556 , 2020 Oct , V21 (20) doi: 10.3390/ijms21207681
Modification of Serine 1040 of SIBRI1 Increases Fruit Yield by Enhancing Tolerance to Heat Stress in Tomato.
State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, China.; Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China.
High temperature is a major environmental factor that adversely affects plant growth and production. SlBRI1 is a critical receptor in brassinosteroid signalling, and its phosphorylation sites have differential functions in plant growth and development. However, the roles of the phosphorylation sites of SIBRI1 in stress tolerance are unknown. In this study, we investigated the biological functions of the phosphorylation site serine 1040 (Ser-1040) of SlBRI1 in tomato. Phenotype analysis indicated that transgenic tomato harbouring SlBRI1 dephosphorylated at Ser-1040 showed increased tolerance to heat stress, exhibiting better plant growth and plant yield under high temperature than transgenic lines expressing SlBRI1 or SlBRI1 phosphorylated at Ser-1040. Biochemical and physiological analyses further showed that antioxidant activity, cell membrane integrity, osmo-protectant accumulation, photosynthesis and transcript levels of heat stress defence genes were all elevated in tomato plants harbouring SlBRI1 dephosphorylated at Ser-1040, and the autophosphorylation level of SlBRI1 was inhibited when SlBRI1 dephosphorylated at Ser-1040. Taken together, our results demonstrate that the phosphorylation site Ser-1040 of SlBRI1 affects heat tolerance, leading to improved plant growth and yield under high-temperature conditions. Our results also indicate the promise of phosphorylation site modification as an approach for protecting crop yields from high-temperature stress.
PMID: 33081382
J Agric Food Chem , IF:4.192 , 2020 Oct , V68 (43) : P11987-11996 doi: 10.1021/acs.jafc.0c04466
Brassinosteroid Regulates 3-Hydroxy-3-methylglutaryl CoA Reductase to Promote Grape Fruit Development.
College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.; China Wine Industry Technology Institute, Yinchuan 750000, China.
Brassinosteroids (BRs) are known to regulate plant growth and development. However, only little is known about their mechanism in the regulation of berry development in grapes. This study demonstrates that BR treatment enhances the accumulation of fruit sugar components, reduces the content of organic acids (e.g., tartaric acid), promotes coloration, and increases the anthocyanin content in grape berries at the onset of the veraison, half veraison, and full veraison stages at the rate of 0.0998, 0.0560, and 0.0281 mg.g(-1), respectively. In addition, BR treatment was also found to accelerate the biosynthesis of terpenoid aroma components, such as alpha-pinene, d-limonene, and gamma-terpinene, which influence the aromatic composition of grapes. BRs can negatively regulate the expression of VvHMGR, a key gene involved in the mevalonate (MVA) pathway, and reduce the activity of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR). Inhibiting the expression of HMGR promoted the accumulation of anthocyanins and fruit coloration. Meanwhile, after the inhibition, the contents of auxin indole-3-acetic acid (IAA), abscisic acid (ABA), and brassinosteroid (BR) increased, while gibberellin (GA3) and zeatin riboside (ZR) decreased, and its aromatic composition also changed. Therefore, it may be concluded that BRs inhibited HMGR activity and cooperated with VvHMGR to regulate the formation of color, aroma, and other quality characteristics in fruits.
PMID: 33059448
Ann Bot , IF:4.005 , 2020 Oct , V126 (5) : P807-824 doi: 10.1093/aob/mcaa121
Associations between phytohormones and cellulose biosynthesis in land plants.
School of Biosciences, University of Melbourne, Parkville, Victoria, Australia.; Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, USA.; Department of Chemistry, University of Nevada, Reno, Nevada, USA.
BACKGROUND: Phytohormones are small molecules that regulate virtually every aspect of plant growth and development, from basic cellular processes, such as cell expansion and division, to whole plant environmental responses. While the phytohormone levels and distribution thus tell the plant how to adjust itself, the corresponding growth alterations are actuated by cell wall modification/synthesis and internal turgor. Plant cell walls are complex polysaccharide-rich extracellular matrixes that surround all plant cells. Among the cell wall components, cellulose is typically the major polysaccharide, and is the load-bearing structure of the walls. Hence, the cell wall distribution of cellulose, which is synthesized by large Cellulose Synthase protein complexes at the cell surface, directs plant growth. SCOPE: Here, we review the relationships between key phytohormone classes and cellulose deposition in plant systems. We present the core signalling pathways associated with each phytohormone and discuss the current understanding of how these signalling pathways impact cellulose biosynthesis with a particular focus on transcriptional and post-translational regulation. Because cortical microtubules underlying the plasma membrane significantly impact the trajectories of Cellulose Synthase Complexes, we also discuss the current understanding of how phytohormone signalling impacts the cortical microtubule array. CONCLUSION: Given the importance of cellulose deposition and phytohormone signalling in plant growth and development, one would expect that there is substantial cross-talk between these processes; however, mechanisms for many of these relationships remain unclear and should be considered as the target of future studies.
PMID: 32619216
Sci Rep , IF:3.998 , 2020 Oct , V10 (1) : P17329 doi: 10.1038/s41598-020-73677-x
Role of myo-inositol during skotomorphogenesis in Arabidopsis.
Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.; Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India. param@genomeindia.org.
Myo-inositol is a ubiquitous metabolite of plants. It is synthesized by a highly conserved enzyme L-myo-inositol phosphate synthase (MIPS; EC 5.5.1.4). Myo-inositol is well characterized during abiotic stress tolerance but its role during growth and development is unclear. In this study, we demonstrate that the apical hook maintenance and hypocotyl growth depend on myo-inositol. We discovered the myo-inositol role during hook formation and its maintenance via ethylene pathway in Arabidopsis by supplementation assays and qPCR. Our results suggest an essential requirement of myo-inositol for mediating the ethylene response and its interaction with brassinosteroid to regulate the skotomorphogenesis. A model is proposed outlining how MIPS regulates apical hook formation and hypocotyl growth.
PMID: 33060662
3 Biotech , IF:1.798 , 2020 Nov , V10 (11) : P466 doi: 10.1007/s13205-020-02454-4
Plant growth regulators: a sustainable approach to combat pesticide toxicity.
School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, Punjab 144411 India.grid.449005.c; Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab 143005 India.grid.411894.10000 0001 0726 8286; Department of Botany, S.P College, Cluster University, Srinagar, Kashmir 190005 India.grid.507608.c
Pesticides are chemical substances intended for preventing or controlling pests. These are toxic substances which contaminate soil, water bodies and vegetative crops. Excessive use of pesticides may cause destruction of biodiversity. In plants, pesticides lead to oxidative stress, inhibition of physiological and biochemical pathways, induce toxicity, impede photosynthesis and negatively affect yield of crops. Increased production of reactive oxygen species like superoxide radicals, O(-) 2 hydrogen peroxide, H2O2; singlet oxygen, O2; hydroxyl radical, OH(-); and hydroperoxyl radical HO2-, causes damage to protein, lipid, carbohydrate and DNA within plants. Plant growth regulators (PGR) are recognized for promoting growth and development under optimal as well as stress conditions. PGR combat adverse effect by acting as chemical messenger and under complex regulation, enable plants to survive under stress conditions. PGR mediate various physiological and biochemical responses, thereby reducing pesticide-induced toxicity. Exogenous applications of PGRs, such as brassinosteroid, cytokinins, salicylic acid, jasmonic acid, etc., mitigate pesticide toxicity by stimulating antioxidant defense system and render tolerance towards stress conditions. They provide resistance against pesticides by controlling production of reactive oxygen species, nutrient homeostasis, increase secondary metabolite production, and trigger antioxidant mechanisms. These phytohormones protect plants against oxidative damage by activating mitogen-stimulated protein kinase cascade. Current study is based on reported research work that has shown the effect of PGR in promoting plant growth subjected to pesticide stress. The present review covers the aspects of pesticidal response of plants and evaluates the contribution of PGRs in mitigating pesticide-induced stress and increasing the tolerance of plants. Further, the study suggests the use of PGRs as a tool in mitigating effects of pesticidal stress together with improved growth and development.
PMID: 33088662
Plant Signal Behav , IF:1.671 , 2020 Oct : P1837544 doi: 10.1080/15592324.2020.1837544
Phytohormones: structural and functional relationship to purine nucleotides and some pharmacologic agents.
Faculty of Life Sciences & Education, University of South Wales , Cardiff, UK.
Structural components of second messenger signaling (nucleotides and associated enzyme systems) within plant and animal cells have more in common than the hormones that initiate metabolic and functional changes. Neurotransmitters and hormones of mammalian pharmacologic classes relate to purine nucleotides in respect of chemical structure and the molecular changes they initiate. This study compares the molecular structures of purine nucleotides with compounds from the abscisic acid, auxin, brassinosteroid, cytokinin, gibberellin, and jasmonate classes by means of a computational program. The results illustrate how phytohomones relate to each other through the structures of nucleotides and cyclic nucleotides. Molecular similarity within the phytohormone structures relates to synergism, antagonism and the modulation of nucleotide function that regulates germination and plant development. As with the molecular evolution of mammalian hormones, cell signaling and cross-talk within the phytohormone classes is purine nucleotide centered.
PMID: 33100143