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.

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.

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 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.

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.

scholarly journals Transcriptome Profiling Provides Insights into Molecular Mechanism in Peanut Semi-dwarf Mutant

2020 ◽  
Author(s):  
Fengdan Guo ◽  
Junjie Ma ◽  
Lei Hou ◽  
Suhua Shi ◽  
Jinbo Sun ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Plant Height ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Main Stem ◽  
Differentially Expressed ◽  
Dwarf Mutant ◽  
Mature Stage ◽  
Stem Height

Abstract Background: Plant height, mainly decided by main stem height, is the major agronomic trait and closely correlated to crop yield. A number of studies had been conducted on model plants and crops to understand the molecular and genetic basis of plant height. However, little is known on the molecular mechanisms of peanut main stem height. Results: In this study, a semi-dwarf peanut mutant was identified from 60 Co γ-ray induced mutant population and designated as semi-dwarf mutant 2 ( sdm2 ). The height of sdm2 was only 59.3% of its wild line Fenghua 1 (FH1) at the mature stage. The sdm2 has less internode number and short internode length to compare with FH1. Gene expression profiles of stem and leaf from both sdm2 and FH1 were analyzed using high throughput RNA sequencing. The differentially expressed genes (DEGs) were involved in hormone biosynthesis and signaling pathways, cell wall synthetic and metabolic pathways. BR, GA and IAA biosynthesis and signal transduction pathways were significantly enriched. The expression of several genes in BR biosynthesis and signaling were found to be significantly down-regulated in sdm2 as compared to FH1. Many transcription factors encoding genes were identified as DEGs. Conclusions: A large number of genes were found differentially expressed between sdm2 and FH1. These results provide useful information for uncovering the molecular mechanism regulating peanut stem height. It could facilitate identification of causal genes for breeding peanut varieties with semi-dwarf phenotype.

scholarly journals Transcriptome Profiling Provides Insights into Molecular Mechanism in Peanut Semi-dwarf Mutant

2020 ◽  
Author(s):  
Fengdan Guo ◽  
Junjie Ma ◽  
Lei Hou ◽  
Suhua Shi ◽  
Jinbo Sun ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Plant Height ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Main Stem ◽  
Differentially Expressed ◽  
Dwarf Mutant ◽  
Mature Stage ◽  
Stem Height

Abstract Background: Plant height, mainly decided by main stem height, is the major agronomic trait and closely correlated to crop yield. A number of studies had been conducted on model plants and crops to understand the molecular and genetic basis of plant height. However, little is known on the molecular mechanisms of peanut main stem height. Results: In this study, a semi-dwarf peanut mutant was identified from 60 Co γ-ray induced mutant population and designated as semi-dwarf mutant 2 ( sdm2 ). The height of sdm2 was only 59.3% of its wild line Fenghua 1 (FH1) at the mature stage. The sdm2 has less internode number and short internode length to compare with FH1. Gene expression profiles of stem and leaf from both sdm2 and FH1 were analyzed using high throughput RNA sequencing. The differentially expressed genes (DEGs) were involved in hormone biosynthesis and signaling pathways, cell wall synthetic and metabolic pathways. BR, GA and IAA biosynthesis and signal transduction pathways were significantly enriched. The expression of several genes in BR biosynthesis and signaling were found to be significantly down-regulated in sdm2 as compared to FH1. Many transcription factors encoding genes were identified as DEGs. Conclusions: A large number of genes were found differentially expressed between sdm2 and FH1. These results provide useful information for uncovering the molecular mechanism regulating peanut stem height. It could facilitate identification of causal genes for breeding peanut varieties with semi-dwarf phenotype.

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 MtPIN1 and MtPIN3 Play Dual Roles in Regulation of Shade Avoidance Response under Different Environments in Medicago truncatula

2020 ◽  
Vol 21 (22) ◽  
pp. 8742
Author(s):  
Xue Zhang ◽  
Lu Liu ◽  
Hongfeng Wang ◽  
Zhiqun Gu ◽  
Yafei Liu ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Auxin Transport ◽  
Stem Elongation ◽  
Normal Growth ◽  
Shade Avoidance ◽  
Dual Roles ◽  
Model Legume ◽  
Auxin Synthesis ◽  
Asymmetric Distributions ◽  
R:Fr Ratio

Polar auxin transport mediated by PIN-FORMED (PIN) proteins is critical for plant growth and development. As an environmental cue, shade stimulates hypocotyls, petiole, and stem elongation by inducing auxin synthesis and asymmetric distributions, which is modulated by PIN3,4,7 in Arabidopsis. Here, we characterize the MtPIN1 and MtPIN3, which are the orthologs of PIN3,4,7, in model legume species Medicago truncatula. Under the low Red:Far-Red (R:FR) ratio light, the expression of MtPIN1 and MtPIN3 is induced, and shadeavoidance response is disrupted in mtpin1 mtpin3 double mutant, indicating that MtPIN1 and MtPIN3 have a conserved function in shade response. Surprisingly, under the normal growth condition, mtpin1 mtpin3 displayed the constitutive shade avoidance responses, such as the elongated petiole, smaller leaf, and increased auxin and chlorophyll content. Therefore, MtPIN1 and MtPIN3 play dual roles in regulation of shadeavoidance response under different environments. Furthermore, these data suggest that PIN3,4,7 and its orthologs have evolved conserved and specific functions among species.

scholarly journals UGT84F9 is the major flavonoid UDP-glucuronosyltransferase in Medicago truncatula

2021 ◽  
Author(s):  
Olubu A Adiji ◽  
Maite L Docampo-Palacios ◽  
Anislay Alvarez-Hernandez ◽  
Giulio M Pasinetti ◽  
Xiaoqiang Wang ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Phase Ii ◽  
Loss Of Function ◽  
In Planta ◽  
Model Legume ◽  
Flavonoid Compounds ◽  
Wide Range ◽  
Udp Glucuronosyltransferase ◽  
Phase Ii Metabolites

Abstract Mammalian phase II metabolism of dietary plant flavonoid compounds generally involves substitution with glucuronic acid. In contrast, flavonoids mainly exist as glucose conjugates in plants, and few plant UDP-glucuronosyltransferase enzymes have been identified to date. In the model legume Medicago truncatula, the major flavonoid compounds in the aerial parts of the plant are glucuronides of the flavones apigenin and luteolin. Here we show that the M. truncatula glycosyltransferase UGT84F9 is a bi-functional glucosyl/glucuronosyl transferase in vitro, with activity against a wide range of flavonoid acceptor molecules including flavones. However, analysis of metabolite profiles in leaves and roots of M. truncatula ugt84f9 loss of function mutants revealed that the enzyme is essential for formation of flavonoid glucuronides, but not most flavonoid glucosides, in planta. We discuss the use of plant UGATs for the semi-synthesis of flavonoid phase II metabolites for clinical studies.

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