Dwarf and Increased Branching 1 controls plant height and axillary bud outgrowth in Medicago truncatula

2020 ◽  
Vol 71 (20) ◽  
pp. 6355-6365
Author(s):  
Xiaojia Zhang ◽  
Liangliang He ◽  
Baolin Zhao ◽  
Shaoli Zhou ◽  
Youhan Li ◽  
...  
Keyword(s):  
Plant Height ◽  
Medicago Truncatula ◽  
Plant Architecture ◽  
Molecular Mechanisms ◽  
Crop Yields ◽  
Crop Improvement ◽  
Axillary Bud ◽  
Loss Of Function ◽  
Model Legume ◽  
Axillary Bud Outgrowth

Abstract Optimizing plant architecture is an efficient approach for breeders to increase crop yields, and phytohormones such as gibberellins (GAs) play an important role in controlling growth. Medicago truncatula is a model legume species, but the molecular mechanisms underlying its architecture are largely unknown. In this study, we examined a tobacco retrotransposon Tnt1-tagged mutant collection of M. truncatula and identified dwarf and increased branching 1 (dib1), which exhibited extreme dwarfism and increased numbers of lateral branches. By analysis of the flanking sequences of Tnt1 insertions in different alleles of the tagged lines, we were able to clone DIB1. Linkage analysis and reverse screening of the flanking-sequence tags identified Medtr2g102570 as the gene corresponding to the DIB1 locus in the dib1 loss-of-function mutants. Phylogenetic analysis indicated that DIB1 was the ortholog of PsGA3ox1/Le in Pisum sativum. Expression analysis using a GUS-staining reporter line showed that DIB1 was expressed in the root apex, pods, and immature seeds. Endogenous GA4 concentrations were markedly decreased whilst some of representative GA biosynthetic enzymes were up-regulated in the dib1 mutant. In addition, exogenous application of GA3 rescued the dib1 mutant phenotypes. Overall, our results suggest that DIB1 controls plant height and axillary bud outgrowth via an influence on the biosynthesis of bioactive GAs. DIB1 could therefore be a good candidate gene for breeders to optimize plant architecture for crop improvement.

scholarly journals The GA 20-Oxidase Encoding Gene MSD1 Controls the Main Stem Elongation in Medicago truncatula

2021 ◽  
Vol 12 ◽  
Author(s):  
Wanying Li ◽  
Qingxia Ma ◽  
Pengcheng Yin ◽  
Jiangqi Wen ◽  
Yanxi Pei ◽  
...  
Keyword(s):  
Plant Height ◽  
Medicago Truncatula ◽  
Crop Production ◽  
Molecular Mechanisms ◽  
Stem Elongation ◽  
Biologically Active ◽  
Main Stem ◽  
Loss Of Function ◽  
Main Shoot ◽  
Model Legume

Plant height is an important agronomic trait that is closely related to biomass yield and crop production. Despite legumes comprise one of the largest monophyletic families that are second only to grasses in terms of economic and nutritional values, due to an ancient genome duplication event, most legume plants have complex genomes, thus the molecular mechanisms that determine plant height are less known in legumes. Here, we report the identification and characterization of MAIN STEM DWARF1 (MSD1), which is required for the plant height in the model legume Medicago truncatula. Loss of function of MSD1 leads to severely reduced main stem height but normal lateral branch elongation in M. truncatula. Histological analysis revealed that the msd1-1 main stem has shorter internodes with reduced cell size and number compared with the wild type, indicating that MSD1 affects cell elongation and cell proliferation. MSD1 encodes a putative GA 20-oxidase that is expressed at significantly higher levels in the main shoot apex than in the lateral shoot apices, suggesting that MSD1 expression is associated with its effect on the main stem elongation. UPLC-MS/MS analysis showed that GA9 and GA4, two identified products of the GA 20-oxidase, were severely reduced in msd1-1, and the dwarf phenotype of msd1-1 could be rescued by supplementation with gibberellic acid GA3, confirming that MSD1 functions as a biologically active GA 20-oxidase. Moreover, we found that disruption of either MtGA20ox7 or MtGA20ox8, homologs of MSD1, has little effects on the elongation of the main stem, while the msd1-1 mtga20ox7-1 mtga20ox8 triple mutants exhibits a severe short main shoot and lateral branches, as well as reduced leaf size, suggesting that MSD1 and its homologs MtGA20ox7 and MtGA20ox8, redundantly regulate M. truncatula shoot elongation and leaf development. Taken together, our findings demonstrate the molecular mechanism of MSD1-mediated regulation of main stem elongation in M. truncatula and provide insights into understanding the functional diversity of GA 20-oxidases in optimizing plant architecture in legumes.

scholarly journals Cloning and Functional Analysis of Dwarf Gene Mini Plant 1 (MNP1) in Medicago truncatula

2020 ◽  
Vol 21 (14) ◽  
pp. 4968
Author(s):  
Shiqi Guo ◽  
Xiaojia Zhang ◽  
Quanzi Bai ◽  
Weiyue Zhao ◽  
Yuegenwang Fang ◽  
...  
Keyword(s):  
Plant Height ◽  
Medicago Truncatula ◽  
Crop Yields ◽  
Genetic Regulation ◽  
Cell Number ◽  
Lodging Resistance ◽  
Dwarf Gene ◽  
Model Legume ◽  
Close Relationship ◽  
Ga Biosynthesis

Plant height is a vital agronomic trait that greatly determines crop yields because of the close relationship between plant height and lodging resistance. Legumes play a unique role in the worldwide agriculture; however, little attention has been given to the molecular basis of their height. Here, we characterized the first dwarf mutant mini plant 1 (mnp1) of the model legume plant Medicago truncatula. Our study found that both cell length and the cell number of internodes were reduced in a mnp1 mutant. Using the forward genetic screening and subsequent whole-genome resequencing approach, we cloned the MNP1 gene and found that it encodes a putative copalyl diphosphate synthase (CPS) implicated in the first step of gibberellin (GA) biosynthesis. MNP1 was highly homologous to Pisum sativum LS. The subcellular localization showed that MNP1 was located in the chloroplast. Further analysis indicated that GA3 could significantly restore the plant height of mnp1-1, and expression of MNP1 in a cps1 mutant of Arabidopsis partially rescued its mini-plant phenotype, indicating the conservation function of MNP1 in GA biosynthesis. Our results provide valuable information for understanding the genetic regulation of plant height in M. truncatula.

The interaction between MtDELLA-MtGAF1 complex and MtARF3 mediates transcriptional control of MtGA3ox1 to elaborate leaf margin formation in Medicago truncatula

2021 ◽  
Author(s):  
Lizhu Wen ◽  
Yiming Kong ◽  
Hongfeng Wang ◽  
Yiteng Xu ◽  
Zhichao Lu ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Medicago Truncatula ◽  
Transcriptional Control ◽  
Molecular Mechanisms ◽  
Leaf Shape ◽  
Critical Role ◽  
Competitive Inhibitor ◽  
Leaf Margin ◽  
Loss Of Function ◽  
Model Legume

Abstract The molecular mechanisms underlying diversity of leaf shapes have been of great interest to researchers. Leaf shape depends on the pattern of serrations and the degree of indentation of leaf margins. Multiple transcription factors and hormone signaling are involved in this process. In this study, we characterized the developmental roles of SMALL AND SERRATED LEAF (SSL) by analyzing a recessive mutant in the model legume Medicago truncatula. An ortholog of Arabidopsis thaliana GA3-oxidase 1 (GA3ox1), MtGA3ox1/SSL, is required for GA biosynthesis. Loss of function in MtGA3ox1 results in the small plant and lateral organs. The prominent phenotype of the mtga3ox1 mutant is the more pronounced leaf margin, indicating the critical role of GA level in leaf margin formation. Moreover, 35S: MtDELLA2  ΔDELLAand 35S: MtARF3 transgenic plants display leaves with the deeply wavy margin, which resembles those of mtga3ox1. Further investigations show that the MtGA3ox1 is under the control of MtDELLA1/2/3-MtGAF1 complexes-dependent feedback regulation. Meanwhile, MtARF3 behaves as a competitive inhibitor of MtDELLA2/3-MtGAF1 complexes to repress the expression of MtGA3ox1 indirectly. These findings suggest that GA feedback regulatory circuits play a fundamental role in leaf margin formation, in which the posttranslational interaction between transcription factors functions as an additional feature.

scholarly journals AGLF provides C-function in floral organ identity through transcriptional regulation of AGAMOUS in Medicago truncatula

2019 ◽  
Vol 116 (11) ◽  
pp. 5176-5181 ◽  
Author(s):  
Yang Zhao ◽  
Rong Liu ◽  
Yiteng Xu ◽  
Minmin Wang ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Flower Development ◽  
Molecular Mechanisms ◽  
Floral Organ ◽  
Model Systems ◽  
Loss Of Function ◽  
Model Legume ◽  
Floral Organ Identity ◽  
Organ Identity ◽  
Class B

Floral development is one of the model systems for investigating the mechanisms underlying organogenesis in plants. Floral organ identity is controlled by the well-known ABC model, which has been generalized to many flowering plants. Here, we report a previously uncharacterized MYB-like gene, AGAMOUS-LIKE FLOWER (AGLF), involved in flower development in the model legume Medicago truncatula. Loss-of-function of AGLF results in flowers with stamens and carpel transformed into extra whorls of petals and sepals. Compared with the loss-of-function mutant of the class C gene AGAMOUS (MtAG) in M. truncatula, the defects in floral organ identity are similar between aglf and mtag, but the floral indeterminacy is enhanced in the aglf mutant. Knockout of AGLF in the mutants of the class A gene MtAP1 or the class B gene MtPI leads to an addition of a loss-of-C-function phenotype, reflecting a conventional relationship of AGLF with the canonical A and B genes. Furthermore, we demonstrate that AGLF activates MtAG in transcriptional levels in control of floral organ identity. These data shed light on the conserved and diverged molecular mechanisms that control flower development and morphology among plant species.

scholarly journals A New RING Finger Protein, PLANT ARCHITECTURE and GRAIN NUMBER 1, Affects Plant Architecture and Grain Yield in Rice

2022 ◽  
Vol 23 (2) ◽  
pp. 824
Author(s):  
Peiwen Yan ◽  
Yu Zhu ◽  
Ying Wang ◽  
Fuying Ma ◽  
Dengyong Lan ◽  
...  
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Plant Architecture ◽  
Crop Improvement ◽  
Ring Finger ◽  
Cell Number ◽  
Ring Finger Protein ◽  
Loss Of Function ◽  
Grain Number ◽  
New Gene

Developing methods for increasing the biomass and improving the plant architecture is important for crop improvement. We herein describe a gene belonging to the RING_Ubox (RING (Really Interesting New Gene) finger domain and U-box domain) superfamily, PLANT ARCHITECTURE and GRAIN NUMBER 1 (PAGN1), which regulates the number of grains per panicle, the plant height, and the number of tillers. We used the CRISPR/Cas9 system to introduce loss-of-function mutations to OsPAGN1. Compared with the control plants, the resulting pagn1 mutant plants had a higher grain yield because of increases in the plant height and in the number of tillers and grains per panicle. Thus, OsPAGN1 may be useful for the genetic improvement of plant architecture and yield. An examination of evolutionary relationships revealed that OsPAGN1 is highly conserved in rice. We demonstrated that OsPAGN1 can interact directly with OsCNR10 (CELL NUMBER REGULATOR10), which negatively regulates the number of rice grains per panicle. A transcriptome analysis indicated that silencing OsPAGN1 affects the levels of active cytokinins in rice. Therefore, our findings have clarified the OsPAGN1 functions related to rice growth and grain development.

scholarly journals Sinorhizobium meliloti Controls Nitric Oxide–Mediated Post-Translational Modification of a Medicago truncatula Nodule Protein

2015 ◽  
Vol 28 (12) ◽  
pp. 1353-1363 ◽  
Author(s):  
Pauline Blanquet ◽  
Liliana Silva ◽  
Olivier Catrice ◽  
Claude Bruand ◽  
Helena Carvalho ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Molecular Mechanisms ◽  
Root Nodules ◽  
Plant Protein ◽  
Post Translational Modification ◽  
Model Legume ◽  
Bacterial Mutants

Nitric oxide (NO) is involved in various plant-microbe interactions. In the symbiosis between soil bacterium Sinorhizobium meliloti and model legume Medicago truncatula, NO is required for an optimal establishment of the interaction but is also a signal for nodule senescence. Little is known about the molecular mechanisms responsible for NO effects in the legume-rhizobium interaction. Here, we investigate the contribution of the bacterial NO response to the modulation of a plant protein post-translational modification in nitrogen-fixing nodules. We made use of different bacterial mutants to finely modulate NO levels inside M. truncatula root nodules and to examine the consequence on tyrosine nitration of the plant glutamine synthetase, a protein responsible for assimilation of the ammonia released by nitrogen fixation. Our results reveal that S. meliloti possesses several proteins that limit inactivation of plant enzyme activity via NO-mediated post-translational modifications. This is the first demonstration that rhizobia can impact the course of nitrogen fixation by modulating the activity of a plant protein.

Integrating the dynamics of yield traits in rice in response to environmental changes

2019 ◽  
Vol 71 (2) ◽  
pp. 490-506 ◽  
Author(s):  
Kamlesh Kant Nutan ◽  
Ray Singh Rathore ◽  
Amit Kumar Tripathi ◽  
Manjari Mishra ◽  
Ashwani Pareek ◽  
...  
Keyword(s):  
Plant Architecture ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Crop Yields ◽  
Current Knowledge ◽  
Global Climate ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Yield Traits ◽  
Comprehensive Understanding

Abstract Reductions in crop yields as a consequence of global climate change threaten worldwide food security. It is therefore imperative to develop high-yielding crop plants that show sustainable production under stress conditions. In order to achieve this aim through breeding or genetic engineering, it is crucial to have a complete and comprehensive understanding of the molecular basis of plant architecture and the regulation of its sub-components that contribute to yield under stress. Rice is one of the most widely consumed crops and is adversely affected by abiotic stresses such as drought and salinity. Using it as a model system, in this review we present a summary of our current knowledge of the physiological and molecular mechanisms that determine yield traits in rice under optimal growth conditions and under conditions of environmental stress. Based on physiological functioning, we also consider the best possible combination of genes that may improve grain yield under optimal as well as environmentally stressed conditions. The principles that we present here for rice will also be useful for similar studies in other grain crops.

scholarly journals Rice Transcription Factor OsWRKY55 Is Involved in the Drought Response and Regulation of Plant Growth

2021 ◽  
Vol 22 (9) ◽  
pp. 4337
Author(s):  
Kai Huang ◽  
Tao Wu ◽  
Ziming Ma ◽  
Zhao Li ◽  
Haoyuan Chen ◽  
...  
Keyword(s):  
Drought Stress ◽  
Plant Growth ◽  
Plant Height ◽  
Molecular Mechanisms ◽  
Crop Improvement ◽  
Critical Role ◽  
Luciferase Reporter ◽  
Mitogen Activated Protein ◽  
Two Hybrid ◽  
Dual Luciferase Reporter Assay

WRKY transcription factors (TFs) have been reported to respond to biotic and abiotic stresses and regulate plant growth and development. However, the molecular mechanisms of WRKY TFs involved in drought stress and regulating plant height in rice remain largely unknown. In this study, we found that transgenic rice lines overexpressing OsWRKY55 (OsWRKY55-OE) exhibited reduced drought resistance. The OsWRKY55-OE lines showed faster water loss and greater accumulation of hydrogen peroxide (H2O2) and superoxide radical (O2−·) compared to wild-type (WT) plants under drought conditions. OsWRKY55 was expressed in various tissues and was induced by drought and abscisic acid (ABA) treatments. Through yeast two-hybrid assays, we found that OsWRKY55 interacted with four mitogen-activated protein kinases (MAPKs) that could be induced by drought, including OsMPK7, OsMPK9, OsMPK20-1, and OsMPK20-4. The activation effects of the four OsMPKs on OsWRKY55 transcriptional activity were demonstrated by a GAL4-dependent chimeric transactivation assay in rice protoplasts. Furthermore, OsWRKY55 was able to reduce plant height under normal conditions by decreasing the cell size. In addition, based on a dual luciferase reporter assay, OsWRKY55 was shown to bind to the promoter of OsAP2-39 through a yeast one-hybrid assay and positively regulate OsAP2-39 expression. These results suggest that OsWRKY55 plays a critical role in responses to drought stress and the regulation of plant height in rice, further providing valuable information for crop improvement.

scholarly journals The Genetic Control of the Compound Leaf Patterning in Medicago truncatula

2022 ◽  
Vol 12 ◽  
Author(s):  
Xiaoyu Mo ◽  
Liangliang He ◽  
Ye Liu ◽  
Dongfa Wang ◽  
Baolin Zhao ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Genetic Control ◽  
Medicago Truncatula ◽  
Molecular Mechanisms ◽  
Molecular Design ◽  
Current Knowledge ◽  
Leaf Morphogenesis ◽  
Model Legume ◽  
Compound Leaf ◽  
Leaf Patterning

Simple and compound which are the two basic types of leaves are distinguished by the pattern of the distribution of blades on the petiole. Compared to simple leaves comprising a single blade, compound leaves have multiple blade units and exhibit more complex and diverse patterns of organ organization, and the molecular mechanisms underlying their pattern formation are receiving more and more attention in recent years. Studies in model legume Medicago truncatula have led to an improved understanding of the genetic control of the compound leaf patterning. This review is an attempt to summarize the current knowledge about the compound leaf morphogenesis of M. truncatula, with a focus on the molecular mechanisms involved in pattern formation. It also includes some comparisons of the molecular mechanisms between leaf morphogenesis of different model species and offers useful information for the molecular design of legume crops.

scholarly journals A BIN2-like1 Protein Confers Dwarf by Interacting with BZR1 of Brassinosteroid Signaling in Allotetraploid Brassica Napus

2021 ◽  
Author(s):  
Mao Yang ◽  
Jianbo He ◽  
Shubei Wan ◽  
Weiyan Li ◽  
Wenjing Chen ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Plant Height ◽  
Plant Architecture ◽  
Molecular Mechanisms ◽  
Glycogen Synthase ◽  
Molecular Evidence ◽  
Dwarf Phenotype ◽  
Brassinosteroid Signaling ◽  
Successive Generations

Abstract Brassinosteroids (BRs) are steroid hormones that play essential roles in plant growth and development. In this study, we identified a new dwarf mutant in Brassica napus. By map-based cloning, BnaC04.BIL1 (BnaC04g41660D) gene, a BIN2-like1 (BIL1) encoding a GLYCOGEN SYNTHASE KINASE 3 (GSK3-like) protein kinase, was isolated. To date, how BIL1 involves in BR signal transduction remains uncovered. Genetic transformation experiments confirmed that the BnaC04.BIL1 is responsible for the plant dwarf phenotype in the Bndwarf2 mutants. Overexpression of BnaC04.BIL1 not only reduced plant height, but also resulted in compact plant architecture. Using CRISPR/Cas9, two sgRNAs were designed to target BnaC04.BIL1 gene. The gene editing experiments generated mutations of BnaC04.BIL1 sequence, which were stably transmitted to successive generations, and lead to restoration of plant height and plant architecture. The molecular mechanism of Bndwarf2 dwarfing was further verified by Y2H and BiFC assays. Results shown that a Thr187Ser amino acid substitution residing in the conserved region promotes the interaction between BnaC04.BIL1Mut with BnaBZR1, thus enhances the negative regulation of plant growth. The genetic and molecular evidence clarifies first the BnaC04.BIL1 can sharply change plant architecture in natural plant accessions in allotetraploid, and provides new insights into the molecular mechanisms of BR signaling.

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