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Huang R, Jiang S, Dai M, Shi H, Zhu H, Guo Z. Zinc finger transcription factor MtZPT2-2 negatively regulates salt tolerance in Medicago truncatula. PLANT PHYSIOLOGY 2023; 194:564-577. [PMID: 37801609 DOI: 10.1093/plphys/kiad527] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 10/08/2023]
Abstract
Zinc finger proteins (ZFPs) are transcription factors involved in multiple cellular functions. We identified a C2H2 type ZFP (MtZPT2-2) in Medicago truncatula and demonstrated that it localizes to the nucleus and inhibits the transcription of 2 genes encoding high-affinity potassium transporters (MtHKT1;1 and MtHKT1;2). MtZPT2-2 transcripts were detected in stem, leaf, flower, seeds and roots, with the highest level in the xylem and phloem of roots and stems. MtZPT2-2 transcription in leaves was reduced after salt stress. Compared with the wild-type (WT), transgenic lines overexpressing MtZPT2-2 had decreased salt tolerance, while MtZPT2-2-knockout mutants showed increased salt tolerance. MtHKT1;1 and MtHKT1;2 transcripts and Na+ accumulation in shoots and roots, as well as in the xylem of all genotypes of plants, were increased after salt treatment, with higher levels of MtHKT1;1 and MtHKT1;2 transcripts and Na+ accumulation in MtZPT2-2-knockout mutants and lower levels in MtZPT2-2-overexpressing lines compared with the WT. K+ levels showed no significant difference among plant genotypes under salt stress. Moreover, MtZPT2-2 was demonstrated to bind with the promoter of MtHKT1;1 and MtHKT1;2 to inhibit their expression. Antioxidant enzyme activities and the gene transcript levels were accordingly upregulated in response to salt, with higher levels in MtZPT2-2-knockout mutants and lower levels in MtZPT2-2-overexpressing lines compared with WT. The results suggest that MtZPT2-2 regulates salt tolerance negatively through downregulating MtHKT1;1 and MtHKT1;2 expression directly to reduce Na+ unloading from the xylem and regulates antioxidant defense indirectly.
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Affiliation(s)
- Risheng Huang
- College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Shouzhen Jiang
- College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Mengtong Dai
- College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Haifan Shi
- College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Haifeng Zhu
- College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhenfei Guo
- College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
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Iannelli MA, Nicolodi C, Coraggio I, Fabriani M, Baldoni E, Frugis G. A Novel Role of Medicago truncatula KNAT3/4/5-like Class 2 KNOX Transcription Factors in Drought Stress Tolerance. Int J Mol Sci 2023; 24:12668. [PMID: 37628847 PMCID: PMC10454132 DOI: 10.3390/ijms241612668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/02/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Class 2 KNOX homeobox transcription factors (KNOX2) play a role in promoting cell differentiation in several plant developmental processes. In Arabidopsis, they antagonize the meristematic KNOX1 function during leaf development through the modulation of phytohormones. In Medicago truncatula, three KNOX2 genes belonging to the KNAT3/4/5-like subclass (Mt KNAT3/4/5-like or MtKNOX3-like) redundantly works upstream of a cytokinin-signaling module to control the symbiotic root nodule formation. Their possible role in the response to abiotic stress is as-of-yet unknown. We produced transgenic M. truncatula lines, in which the expression of four MtKNOX3-like genes was knocked down by RNA interference. When tested for response to water withdrawal in the soil, RNAi lines displayed a lower tolerance to drought conditions compared to the control lines, measured as increased leaf water loss, accelerated leaf wilting time, and faster chlorophyll loss. Reanalysis of a transcriptomic M. truncatula drought stress experiment via cluster analysis and gene co-expression networks pointed to a possible role of MtKNOX3-like transcription factors in repressing a proline dehydrogenase gene (MtPDH), specifically at 4 days after water withdrawal. Proline measurement and gene expression analysis of transgenic RNAi plants compared to the controls confirmed the role of KNOX3-like genes in inhibiting proline degradation through the regulation of the MtPDH gene.
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Affiliation(s)
- Maria Adelaide Iannelli
- National Research Council (CNR), Institute of Agricultural Biology and Biotechnology (IBBA), Rome Unit, Via Salaria Km. 29,300, Monterotondo Scalo, 00015 Roma, Italy; (M.A.I.); (C.N.); (I.C.); (M.F.)
| | - Chiara Nicolodi
- National Research Council (CNR), Institute of Agricultural Biology and Biotechnology (IBBA), Rome Unit, Via Salaria Km. 29,300, Monterotondo Scalo, 00015 Roma, Italy; (M.A.I.); (C.N.); (I.C.); (M.F.)
| | - Immacolata Coraggio
- National Research Council (CNR), Institute of Agricultural Biology and Biotechnology (IBBA), Rome Unit, Via Salaria Km. 29,300, Monterotondo Scalo, 00015 Roma, Italy; (M.A.I.); (C.N.); (I.C.); (M.F.)
| | - Marco Fabriani
- National Research Council (CNR), Institute of Agricultural Biology and Biotechnology (IBBA), Rome Unit, Via Salaria Km. 29,300, Monterotondo Scalo, 00015 Roma, Italy; (M.A.I.); (C.N.); (I.C.); (M.F.)
| | - Elena Baldoni
- National Research Council (CNR), Institute of Agricultural Biology and Biotechnology (IBBA), Via Alfonso Corti 12, 20133 Milan, Italy;
| | - Giovanna Frugis
- National Research Council (CNR), Institute of Agricultural Biology and Biotechnology (IBBA), Rome Unit, Via Salaria Km. 29,300, Monterotondo Scalo, 00015 Roma, Italy; (M.A.I.); (C.N.); (I.C.); (M.F.)
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Zhang X, Sun Y, Qiu X, Lu H, Hwang I, Wang T. Tolerant mechanism of model legume plant Medicago truncatula to drought, salt, and cold stresses. FRONTIERS IN PLANT SCIENCE 2022; 13:847166. [PMID: 36160994 PMCID: PMC9490062 DOI: 10.3389/fpls.2022.847166] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 08/15/2022] [Indexed: 06/16/2023]
Abstract
Legume plants produce one-third of the total yield of primary crops and are important food sources for both humans and animals worldwide. Frequent exposure to abiotic stresses, such as drought, salt, and cold, greatly limits the production of legume crops. Several morphological, physiological, and molecular studies have been conducted to characterize the response and adaptation mechanism to abiotic stresses. The tolerant mechanisms of the model legume plant Medicago truncatula to abiotic stresses have been extensively studied. Although many potential genes and integrated networks underlying the M. truncatula in responding to abiotic stresses have been identified and described, a comprehensive summary of the tolerant mechanism is lacking. In this review, we provide a comprehensive summary of the adaptive mechanism by which M. truncatula responds to drought, salt, and cold stress. We also discuss future research that need to be explored to improve the abiotic tolerance of legume plants.
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Affiliation(s)
- Xiuxiu Zhang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciencess, Beijing, China
| | - Yu Sun
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciencess, Changchun, China
| | - Xiao Qiu
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Hai Lu
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, South Korea
| | - Tianzuo Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciencess, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
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Nandety RS, Wen J, Mysore KS. Medicago truncatula resources to study legume biology and symbiotic nitrogen fixation. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Li A, Liu A, Wu S, Qu K, Hu H, Yang J, Shrestha N, Liu J, Ren G. Comparison of structural variants in the whole genome sequences of two Medicago truncatula ecotypes: Jemalong A17 and R108. BMC PLANT BIOLOGY 2022; 22:77. [PMID: 35193491 PMCID: PMC8862580 DOI: 10.1186/s12870-022-03469-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Structural variants (SVs) constitute a large proportion of the genomic variation that results in phenotypic variation in plants. However, they are still a largely unexplored feature in most plant genomes. Here, we present the whole-genome landscape of SVs between two model legume Medicago truncatula ecotypes-Jemalong A17 and R108- that have been extensively used in various legume biology studies. RESULTS To catalogue SVs, we first resolved the previously published R108 genome assembly (R108 v1.0) to chromosome-scale using 124 × Hi-C data, resulting in a high-quality genome assembly. The inter-chromosomal reciprocal translocations between chromosomes 4 and 8 were confirmed by performing syntenic analysis between the two genomes. Combined with the Hi-C data, it appears that these translocation events had a significant effect on chromatin organization. Using both whole-genome and short-read alignments, we identified the genomic landscape of SVs between the two genomes, some of which may account for several phenotypic differences, including their differential responses to aluminum toxicity and iron deficiency, and the development of different anthocyanin leaf markings. We also found extensive SVs within the nodule-specific cysteine-rich gene family which encodes antimicrobial peptides essential for terminal bacteroid differentiation during nitrogen-fixing symbiosis. CONCLUSIONS Our results provide a near-complete R108 genome assembly and the first genomic landscape of SVs obtained by comparing two M. truncatula ecotypes. This may provide valuable genomic resources for the functional and molecular research of legume biology in the future.
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Affiliation(s)
- Ao Li
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Ai Liu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Shuang Wu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Kunjing Qu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Hongyin Hu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Jinli Yang
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Nawal Shrestha
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Jianquan Liu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education & State Key Lab of Hydraulics and Mountain River Engineering, College of Life Sciences, Sichuan University, Chengdu, China
| | - Guangpeng Ren
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, China.
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Castañeda V, González EM. Strategies to Apply Water-Deficit Stress: Similarities and Disparities at the Whole Plant Metabolism Level in Medicago truncatula. Int J Mol Sci 2021; 22:ijms22062813. [PMID: 33802151 PMCID: PMC8002188 DOI: 10.3390/ijms22062813] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/06/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Water-deficit stresses such as drought and salinity are the most important factors limiting crop productivity. Hence, understanding the plant responses to these stresses is key for the improvement of their tolerance and yield. In this study M. truncatula plants were subjected to 250 mM NaCl as well as reduced irrigation (No-W) and 250 g/L polyethylene glycol (PEG)-6000 to induce salinity and drought stress, respectively, provoking a drop to −1.7 MPa in leaf water potential. The whole plant physiology and metabolism was explored by characterizing the stress responses at root, phloem sap and leaf organ level. PEG treatment led to some typical responses of plants to drought stress, but in addition to PEG uptake, an important impairment of nutrient uptake and a different regulation of carbon metabolism could be observed compared to No-W plants. No-W plants showed an important redistribution of antioxidants and assimilates to the root tissue, with a distinctive increase in root proline degradation and alkaline invertase activity. On the contrary, salinity provoked an increase in leaf starch and isocitrate dehydrogenase activity, suggesting key roles in the plant response to this stress. Overall, results suggest higher protection of salt-stressed shoots and non-irrigated roots through different mechanisms, including the regulation of proline and carbon metabolism, while discarding PEG as safe mimicker of drought. This raises the need to understand the effect at the whole plant level of the different strategies employed to apply water-deficit stress.
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Arfan M, Zhang DW, Zou LJ, Luo SS, Tan WR, Zhu T, Lin HH. Hydrogen Peroxide and Nitric Oxide Crosstalk Mediates Brassinosteroids Induced Cold Stress Tolerance in Medicago truncatula. Int J Mol Sci 2019; 20:E144. [PMID: 30609774 PMCID: PMC6337477 DOI: 10.3390/ijms20010144] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/19/2018] [Accepted: 12/25/2018] [Indexed: 12/20/2022] Open
Abstract
Brassinosteroids (BRs) play pivotal roles in modulating plant growth, development, and stress responses. In this study, a Medicago truncatula plant pretreated with brassinolide (BL, the most active BR), enhanced cold stress tolerance by regulating the expression of several cold-related genes and antioxidant enzymes activities. Previous studies reported that hydrogen peroxide (H₂O₂) and nitric oxide (NO) are involved during environmental stress conditions. However, how these two signaling molecules interact with each other in BRs-induced abiotic stress tolerance remain largely unclear. BL-pretreatment induced, while brassinazole (BRZ, a specific inhibitor of BRs biosynthesis) reduced H₂O₂ and NO production. Further, application of dimethylthiourea (DMTU, a H₂O₂ and OH- scavenger) blocked BRs-induced NO production, but BRs-induced H₂O₂ generation was not sensitive to 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO, a scavenger of NO). Moreover, pretreatment with DMTU and PTIO decreased BL-induced mitochondrial alternative oxidase (AOX) and the photosystem capacity. However, pretreatment with PTIO was found to be more effective than DMTU in reducing BRs-induced increases in Valt, Vt, and MtAOX1 gene expression. Similarly, BRs-induced photosystem II efficiency was found in NO dependent manner than H₂O₂. Finally, we conclude that H₂O₂ was involved in NO generation, whereas NO was found to be crucial in BRs-induced AOX capacity, which further contributed to the protection of the photosystem under cold stress conditions in Medicago truncatula.
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Affiliation(s)
- Muhammad Arfan
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
| | - Da-Wei Zhang
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
| | - Li-Juan Zou
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
| | - Shi-Shuai Luo
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
| | - Wen-Rong Tan
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
| | - Tong Zhu
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
| | - Hong-Hui Lin
- Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
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Garmier M, Gentzbittel L, Wen J, Mysore KS, Ratet P. Medicago truncatula: Genetic and Genomic Resources. ACTA ACUST UNITED AC 2017; 2:318-349. [PMID: 33383982 DOI: 10.1002/cppb.20058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Medicago truncatula was chosen by the legume community, along with Lotus japonicus, as a model plant to study legume biology. Since then, numerous resources and tools have been developed for M. truncatula. These include, for example, its genome sequence, core ecotype collections, transformation/regeneration methods, extensive mutant collections, and a gene expression atlas. This review aims to describe the different genetic and genomic tools and resources currently available for M. truncatula. We also describe how these resources were generated and provide all the information necessary to access these resources and use them from a practical point of view. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Marie Garmier
- Institute of Plant Sciences Paris-Saclay, Centre National de la Recherche Scientifique, Institut National de Recherche Agronomique, Université Paris-Sud, Université Evry, Université Paris-Saclay, Orsay, France.,Institute of Plant Sciences Paris-Saclay, Université Paris Diderot, Université Sorbonne Paris-Cité, Orsay, France
| | - Laurent Gentzbittel
- EcoLab, Université de Toulouse, Centre National de la Recherche Scientifique, Institut National Polytechnique de Toulouse, Université Paul Sabatier, Castanet-Tolosan, France
| | | | | | - Pascal Ratet
- Institute of Plant Sciences Paris-Saclay, Centre National de la Recherche Scientifique, Institut National de Recherche Agronomique, Université Paris-Sud, Université Evry, Université Paris-Saclay, Orsay, France.,Institute of Plant Sciences Paris-Saclay, Université Paris Diderot, Université Sorbonne Paris-Cité, Orsay, France
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