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Poulet A, Zhao M, Peng Y, Tham F, Jaudal M, Zhang L, van Wolfswinkel JC, Putterill J. Gene-edited Mtsoc1 triple mutant Medicago plants do not flower. FRONTIERS IN PLANT SCIENCE 2024; 15:1357924. [PMID: 38469328 PMCID: PMC10926907 DOI: 10.3389/fpls.2024.1357924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/02/2024] [Indexed: 03/13/2024]
Abstract
Optimized flowering time is an important trait that ensures successful plant adaptation and crop productivity. SOC1-like genes encode MADS transcription factors, which are known to play important roles in flowering control in many plants. This includes the best-characterized eudicot model Arabidopsis thaliana (Arabidopsis), where SOC1 promotes flowering and functions as a floral integrator gene integrating signals from different flowering-time regulatory pathways. Medicago truncatula (Medicago) is a temperate reference legume with strong genomic and genetic resources used to study flowering pathways in legumes. Interestingly, despite responding to similar floral-inductive cues of extended cold (vernalization) followed by warm long days (VLD), such as in winter annual Arabidopsis, Medicago lacks FLC and CO which are key regulators of flowering in Arabidopsis. Unlike Arabidopsis with one SOC1 gene, multiple gene duplication events have given rise to three MtSOC1 paralogs within the Medicago genus in legumes: one Fabaceae group A SOC1 gene, MtSOC1a, and two tandemly repeated Fabaceae group B SOC1 genes, MtSOC1b and MtSOC1c. Previously, we showed that MtSOC1a has unique functions in floral promotion in Medicago. The Mtsoc1a Tnt1 retroelement insertion single mutant showed moderately delayed flowering in long- and short-day photoperiods, with and without prior vernalization, compared to the wild-type. In contrast, Mtsoc1b Tnt1 single mutants did not have altered flowering time or flower development, indicating that it was redundant in an otherwise wild-type background. Here, we describe the generation of Mtsoc1a Mtsoc1b Mtsoc1c triple mutant lines using CRISPR-Cas9 gene editing. We studied two independent triple mutant lines that segregated plants that did not flower and were bushy under floral inductive VLD. Genotyping indicated that these non-flowering plants were homozygous for the predicted strong mutant alleles of the three MtSOC1 genes. Gene expression analyses using RNA-seq and RT-qPCR indicated that these plants remained vegetative. Overall, the non-flowering triple mutants were dramatically different from the single Mtsoc1a mutant and the Arabidopsis soc1 mutant; implicating multiple MtSOC1 genes in critical overlapping roles in the transition to flowering in Medicago.
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Affiliation(s)
- Axel Poulet
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, New Haven, CT, United States
| | - Min Zhao
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Yongyan Peng
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Mt Albert Research Centre, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - FangFei Tham
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Mauren Jaudal
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Mt Albert Research Centre, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Lulu Zhang
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Josien C. van Wolfswinkel
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, New Haven, CT, United States
| | - Joanna Putterill
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Duk MA, Gursky VV, Samsonova MG, Surkova SY. Modeling the Flowering Activation Motif during Vernalization in Legumes: A Case Study of M. trancatula. Life (Basel) 2023; 14:26. [PMID: 38255642 PMCID: PMC10817331 DOI: 10.3390/life14010026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/04/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
In many plant species, flowering is promoted by the cold treatment or vernalization. The mechanism of vernalization-induced flowering has been extensively studied in Arabidopsis but remains largely unknown in legumes. The orthologs of the FLC gene, a major regulator of vernalization response in Arabidopsis, are absent or non-functional in the vernalization-sensitive legume species. Nevertheless, the legume integrator genes FT and SOC1 are involved in the transition of the vernalization signal to meristem identity genes, including PIM (AP1 ortholog). However, the regulatory contribution of these genes to PIM activation in legumes remains elusive. Here, we presented the theoretical and data-driven analyses of a feed-forward regulatory motif that includes a vernalization-responsive FT gene and several SOC1 genes, which independently activate PIM and thereby mediate floral transition. Our theoretical model showed that the multiple regulatory branches in this regulatory motif facilitated the elimination of no-sense signals and amplified useful signals from the upstream regulator. We further developed and analyzed four data-driven models of PIM activation in Medicago trancatula in vernalized and non-vernalized conditions in wild-type and fta1-1 mutants. The model with FTa1 providing both direct activation and indirect activation via three intermediate activators, SOC1a, SOC1b, and SOC1c, resulted in the most relevant PIM dynamics. In this model, the difference between regulatory inputs of SOC1 genes was nonessential. As a result, in the M. trancatula model, the cumulative action of SOC1a, SOC1b, and SOC1c was favored. Overall, in this study, we first presented the in silico analysis of vernalization-induced flowering in legumes. The considered vernalization network motif can be supplemented with additional regulatory branches as new experimental data become available.
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Affiliation(s)
- Maria A. Duk
- Mathematical Biology and Bioinformatics Laboratory, Peter the Great Saint Petersburg Polytechnic University, 195251 St. Petersburg, Russia
- Theoretical Department, Ioffe Institute, 194021 St. Petersburg, Russia
| | - Vitaly V. Gursky
- Theoretical Department, Ioffe Institute, 194021 St. Petersburg, Russia
| | - Maria G. Samsonova
- Mathematical Biology and Bioinformatics Laboratory, Peter the Great Saint Petersburg Polytechnic University, 195251 St. Petersburg, Russia
| | - Svetlana Yu. Surkova
- Mathematical Biology and Bioinformatics Laboratory, Peter the Great Saint Petersburg Polytechnic University, 195251 St. Petersburg, Russia
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Jaudal M, Mayo‐Smith M, Poulet A, Whibley A, Peng Y, Zhang L, Thomson G, Trimborn L, Jacob Y, van Wolfswinkel JC, Goldstone DC, Wen J, Mysore KS, Putterill J. MtING2 encodes an ING domain PHD finger protein which affects Medicago growth, flowering, global patterns of H3K4me3, and gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:1029-1050. [PMID: 36178149 PMCID: PMC9828230 DOI: 10.1111/tpj.15994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 09/04/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Flowering of the reference legume Medicago truncatula is promoted by winter cold (vernalization) followed by long-day photoperiods (VLD) similar to winter annual Arabidopsis. However, Medicago lacks FLC and CO, key regulators of Arabidopsis VLD flowering. Most plants have two INHIBITOR OF GROWTH (ING) genes (ING1 and ING2), encoding proteins with an ING domain with two anti-parallel alpha-helices and a plant homeodomain (PHD) finger, but their genetic role has not been previously described. In Medicago, Mting1 gene-edited mutants developed and flowered normally, but an Mting2-1 Tnt1 insertion mutant and gene-edited Mting2 mutants had developmental abnormalities including delayed flowering particularly in VLD, compact architecture, abnormal leaves with extra leaflets but no trichomes, and smaller seeds and barrels. Mting2 mutants had reduced expression of activators of flowering, including the FT-like gene MtFTa1, and increased expression of the candidate repressor MtTFL1c, consistent with the delayed flowering of the mutant. MtING2 overexpression complemented Mting2-1, but did not accelerate flowering in wild type. The MtING2 PHD finger bound H3K4me2/3 peptides weakly in vitro, but analysis of gene-edited mutants indicated that it was dispensable to MtING2 function in wild-type plants. RNA sequencing experiments indicated that >7000 genes are mis-expressed in the Mting2-1 mutant, consistent with its strong mutant phenotypes. Interestingly, ChIP-seq analysis identified >5000 novel H3K4me3 locations in the genome of Mting2-1 mutants compared to wild type R108. Overall, our mutant study has uncovered an important physiological role of a plant ING2 gene in development, flowering, and gene expression, which likely involves an epigenetic mechanism.
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Affiliation(s)
- Mauren Jaudal
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
| | - Matthew Mayo‐Smith
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
| | - Axel Poulet
- Yale UniversityDepartment of MolecularCellular and Developmental BiologyFaculty of Arts and Sciences260 Whitney AvenueNew HavenCT06511USA
| | - Annabel Whibley
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
| | - Yongyan Peng
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
| | - Lulu Zhang
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
| | - Geoffrey Thomson
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
- Yale UniversityDepartment of MolecularCellular and Developmental BiologyFaculty of Arts and Sciences260 Whitney AvenueNew HavenCT06511USA
| | - Laura Trimborn
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
- Institute for Plant Sciences, BiocenterUniversity of CologneZülpicher Str. 47b50674CologneGermany
| | - Yannick Jacob
- Yale UniversityDepartment of MolecularCellular and Developmental BiologyFaculty of Arts and Sciences260 Whitney AvenueNew HavenCT06511USA
| | - Josien C. van Wolfswinkel
- Yale UniversityDepartment of MolecularCellular and Developmental BiologyFaculty of Arts and Sciences260 Whitney AvenueNew HavenCT06511USA
| | - David C. Goldstone
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
| | - Jiangqi Wen
- Institute for Agricultural BiosciencesOklahoma State University3210 Sam Noble ParkwayArdmoreOK73401USA
| | - Kirankumar S. Mysore
- Institute for Agricultural BiosciencesOklahoma State University3210 Sam Noble ParkwayArdmoreOK73401USA
| | - Joanna Putterill
- School of Biological SciencesUniversity of AucklandPrivate Bag 92019Auckland1142New Zealand
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Surkova SY, Samsonova MG. Mechanisms of Vernalization-Induced Flowering in Legumes. Int J Mol Sci 2022; 23:ijms23179889. [PMID: 36077286 PMCID: PMC9456104 DOI: 10.3390/ijms23179889] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Vernalization is the requirement for exposure to low temperatures to trigger flowering. The best knowledge about the mechanisms of vernalization response has been accumulated for Arabidopsis and cereals. In Arabidopsis thaliana, vernalization involves an epigenetic silencing of the MADS-box gene FLOWERING LOCUS C (FLC), which is a flowering repressor. FLC silencing releases the expression of the main flowering inductor FLOWERING LOCUS T (FT), resulting in a floral transition. Remarkably, no FLC homologues have been identified in the vernalization-responsive legumes, and the mechanisms of cold-mediated transition to flowering in these species remain elusive. Nevertheless, legume FT genes have been shown to retain the function of the main vernalization signal integrators. Unlike Arabidopsis, legumes have three subclades of FT genes, which demonstrate distinct patterns of regulation with respect to environmental cues and tissue specificity. This implies complex mechanisms of vernalization signal propagation in the flowering network, that remain largely elusive. Here, for the first time, we summarize the available information on the genetic basis of cold-induced flowering in legumes with a special focus on the role of FT genes.
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Dong W, Li D, Zhang L, Yin B, Zhang Y. Transcriptome Analysis of Short-Day Photoperiod Inducement in Adzuki Bean ( Vigna angularis L.) Based on RNA-Seq. FRONTIERS IN PLANT SCIENCE 2022; 13:893245. [PMID: 35845693 PMCID: PMC9280645 DOI: 10.3389/fpls.2022.893245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
The flowering characteristics of adzuki bean are influenced by several environmental factors. Light is an important ecological factor that induces flowering in adzuki bean, but to date, there have been few reports on the transcriptomic features of photoperiodic regulation of adzuki bean flowering. This study is based on RNA sequencing (RNA-seq) techniques to elucidate the expression of light-related regulatory genes under short-day photoperiod inducement of adzuki bean flowering, providing an important theoretical basis for its accelerated breeding. Short-day photoperiod inducement of 10 h was conducted for 5 day, 10 day, and 15 day periods on "Tang shan hong xiao dou" varieties, which are more sensitive to short-day photoperiod conditions than the other varieties. Plants grown under natural light (14.5 h) for 5 days, 10 days, and 15 days were used as controls to compare the progress of flower bud differentiation and flowering characteristics. The topmost unfolded functional leaves were selected for transcriptome sequencing and bioinformatics analysis. The short-day photoperiod inducement promoted flower bud differentiation and advanced flowering time in adzuki bean. Transcriptomic analysis revealed 5,608 differentially expressed genes (DEGs) for the combination of CK-5d vs. SD-5d, CK-10d vs. SD-10d, and CK-15d vs. SD-15d. The three groups of the DEGs were analyzed using the Gene Ontology (GO) and the Kyoto Encyclopedia of Genomes and Genomes (KEGG) databases; the DEGs were associated with flowering, photosystem, and the circadian rhythm and were mainly concentrated in the hormone signaling and metabolism, circadian rhythm, and antenna protein pathways; So, 13 light-related genes across the three pathways were screened for differential and expression characteristics. Through the functional annotations of orthologs, these genes were related to flowering, which were supposed to be good candidate genes in adzuki bean. The findings provide a deep understanding of the molecular mechanisms of adzuki bean flowering in response to short-day photoperiod inducement, which laid a foundation for the functional verification of genes in the next step, and provide an important reference for the molecular breeding of adzuki bean.
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Affiliation(s)
- Weixin Dong
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth Regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, China
- Hebei Open University, Shijiazhuang, China
| | - Dongxiao Li
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth Regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, China
| | - Lei Zhang
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth Regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, China
| | - Baozhong Yin
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth Regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, China
| | - Yuechen Zhang
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth Regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, China
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Williams O, Vander Schoor JK, Butler JB, Ridge S, Sussmilch FC, Hecht VFG, Weller JL. The genetic architecture of flowering time changes in pea from wild to crop. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3978-3990. [PMID: 35383838 PMCID: PMC9238443 DOI: 10.1093/jxb/erac132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Abstract
Change in phenology has been an important component in crop evolution, and selection for earlier flowering through a reduction in environmental sensitivity has helped broaden adaptation in many species. Natural variation for flowering in domesticated pea (Pisum sativum L.) has been noted and studied for decades, but there has been no clear account of change relative to its wild progenitor. Here we examined the genetic control of differences in flowering time between wild P. sativum ssp. humile and a typical late-flowering photoperiodic P. s. sativum accession in a recombinant inbred population under long and short photoperiods. Our results confirm the importance of the major photoperiod sensitivity locus Hr/PsELF3a and identify two other loci on chromosomes 1 (DTF1) and 3 (DTF3) that contribute to earlier flowering in the domesticated line under both photoperiods. The domesticated allele at a fourth locus on chromosome 6 (DTF6) delays flowering under long days only. Map positions, inheritance patterns, and expression analyses in near-isogenic comparisons imply that DTF1, DTF3, and DTF6 represent gain-of-function alleles of the florigen/antiflorigen genes FTa3, FTa1, and TFL1c/LF, respectively. This echoes similar variation in chickpea and lentil, and suggests a conserved route to reduced photoperiod sensitivity and early phenology in temperate pulses.
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Affiliation(s)
- Owen Williams
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | | | - Jakob B Butler
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | - Stephen Ridge
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | - Frances C Sussmilch
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | - Valerie F G Hecht
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | - James L Weller
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
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Razzaq MK, Akhter M, Ahmad RM, Cheema KL, Hina A, Karikari B, Raza G, Xing G, Gai J, Khurshid M. CRISPR-Cas9 based stress tolerance: New hope for abiotic stress tolerance in chickpea (Cicer arietinum). Mol Biol Rep 2022; 49:8977-8985. [DOI: 10.1007/s11033-022-07391-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 02/19/2022] [Accepted: 03/16/2022] [Indexed: 02/09/2023]
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8
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Chiurazzi MJ, Nørrevang AF, García P, Cerdán PD, Palmgren M, Wenkel S. Controlling flowering of Medicago sativa (alfalfa) by inducing dominant mutations. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:205-214. [PMID: 34761872 PMCID: PMC9303315 DOI: 10.1111/jipb.13186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
Breeding plants with polyploid genomes is challenging because functional redundancy hampers the identification of loss-of-function mutants. Medicago sativa is tetraploid and obligate outcrossing, which together with inbreeding depression complicates traditional breeding approaches in obtaining plants with a stable growth habit. Inducing dominant mutations would provide an alternative strategy to introduce domestication traits in plants with high gene redundancy. Here we describe two complementary strategies to induce dominant mutations in the M. sativa genome and how they can be relevant in the control of flowering time. First, we outline a genome-engineering strategy that harnesses the use of microProteins as developmental regulators. MicroProteins are small proteins that appeared during genome evolution from genes encoding larger proteins. Genome-engineering allows us to retrace evolution and create microProtein-coding genes de novo. Second, we provide an inventory of genes regulated by microRNAs that control plant development. Making respective gene transcripts microRNA-resistant by inducing point mutations can uncouple microRNA regulation. Finally, we investigated the recently published genomes of M. sativa and provide an inventory of breeding targets, some of which, when mutated, are likely to result in dominant traits.
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Affiliation(s)
- Maurizio Junior Chiurazzi
- NovoCrops CenterUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Copenhagen Plant Science CentreUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
| | - Anton Frisgaard Nørrevang
- NovoCrops CenterUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Copenhagen Plant Science CentreUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
| | - Pedro García
- Fundación Instituto LeloirIIBBA‐CONICETAvenida Patricias Argentinas 435Buenos Aires1405Argentina
| | - Pablo D. Cerdán
- Fundación Instituto LeloirIIBBA‐CONICETAvenida Patricias Argentinas 435Buenos Aires1405Argentina
| | - Michael Palmgren
- NovoCrops CenterUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Copenhagen Plant Science CentreUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
| | - Stephan Wenkel
- NovoCrops CenterUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Copenhagen Plant Science CentreUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
- Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40Frederiksberg C1871Denmark
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Sun Q, Huang R, Zhu H, Sun Y, Guo Z. A novel Medicago truncatula calmodulin-like protein (MtCML42) regulates cold tolerance and flowering time. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1069-1082. [PMID: 34528312 DOI: 10.1111/tpj.15494] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 05/20/2023]
Abstract
Calmodulin-like proteins (CMLs) are one of the Ca2+ sensors in plants, but the functions of most CMLs remain unknown. The regulation of cold tolerance and flowering time by MtCML42 in Medicago truncatula and the underlying mechanisms were investigated using MtCML42-overexpressing plants and cml42 Medicago mutants with a Tnt1 retrotransposon insertion. Compared with the wild type (WT), MtCML42-overexpressing lines had increased cold tolerance, whereas cml42 mutants showed decreased cold tolerance. The impaired cold tolerance in cml42 could b complemented by MtCML42 expression. The transcript levels of MtCBF1, MtCBF4, MtCOR413, MtCAS15, MtLTI6A, MtGolS1 and MtGolS2 and the concentrations of raffinose and sucrose were increased in response to cold treatment, whereas higher levels were observed in MtCML42-overexpressing lines and lower levels were observed in cml42 mutants. In addition, early flowering with upregulated MtFTa1 and downregulated MtABI5 transcripts was observed in MtCML42-overexpressing lines, whereas delayed flowering with downregulated MtFTa1 and upregulated MtABI5 was observed in cml42. MtABI5 expression could complement the flowering phenotype in the Arabidopsis mutant abi5. Our results suggest that MtCML42 positively regulates MtCBF1 and MtCBF4 expression, which in turn upregulates the expression of some COR genes, MtGolS1 and MtGolS2, which leads to raffinose accumulation and increased cold tolerance. MtCML42 regulates flowering time through sequentially downregulating MtABI5 and upregulating MtFTa1 expression.
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Affiliation(s)
- Qiguo Sun
- College of Grassland Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Risheng Huang
- College of Grassland Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Haifeng Zhu
- College of Grassland Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yanmei Sun
- 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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Taylor CM, Garg G, Berger JD, Ribalta FM, Croser JS, Singh KB, Cowling WA, Kamphuis LG, Nelson MN. A Trimethylguanosine Synthase1-like (TGS1) homologue is implicated in vernalisation and flowering time control. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2021; 134:3411-3426. [PMID: 34258645 PMCID: PMC8440268 DOI: 10.1007/s00122-021-03910-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 07/06/2021] [Indexed: 05/30/2023]
Abstract
KEY MESSAGE A plant-specific Trimethylguanosine Synthase1-like homologue was identified as a candidate gene for the efl mutation in narrow-leafed lupin, which alters phenology by reducing vernalisation requirement. The vernalisation pathway is a key component of flowering time control in plants from temperate regions but is not well understood in the legume family. Here we examined vernalisation control in the temperate grain legume species, narrow-leafed lupin (Lupinus angustifolius L.), and discovered a candidate gene for an ethylene imine mutation (efl). The efl mutation changes phenology from late to mid-season flowering and additionally causes transformation from obligate to facultative vernalisation requirement. The efl locus was mapped to pseudochromosome NLL-10 in a recombinant inbred line (RIL) mapping population developed by accelerated single seed descent. Candidate genes were identified in the reference genome, and a diverse panel of narrow-leafed lupins was screened to validate mutations specific to accessions with efl. A non-synonymous SNP mutation within an S-adenosyl-L-methionine-dependent methyltransferase protein domain of a Trimethylguanosine Synthase1-like (TGS1) orthologue was identified as the candidate mutation giving rise to efl. This mutation caused substitution of an amino acid within an established motif at a position that is otherwise highly conserved in several plant families and was perfectly correlated with the efl phenotype in F2 and F6 genetic population and a panel of diverse accessions, including the original efl mutant. Expression of the TGS1 homologue did not differ between wild-type and efl genotypes, supporting altered functional activity of the gene product. This is the first time a TGS1 orthologue has been associated with vernalisation response and flowering time control in any plant species.
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Affiliation(s)
- Candy M Taylor
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, 6009, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6009, Australia
| | - Gagan Garg
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat, WA, 6014, Australia
| | - Jens D Berger
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat, WA, 6014, Australia
| | - Federico M Ribalta
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, 6009, Australia
| | - Janine S Croser
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, 6009, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6009, Australia
| | - Karam B Singh
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6009, Australia
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat, WA, 6014, Australia
- Centre for Crop and Disease Management, Curtin University, Bentley, WA, 6102, Australia
| | - Wallace A Cowling
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, 6009, Australia.
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6009, Australia.
| | - Lars G Kamphuis
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6009, Australia
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat, WA, 6014, Australia
- Centre for Crop and Disease Management, Curtin University, Bentley, WA, 6102, Australia
| | - Matthew N Nelson
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6009, Australia
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat, WA, 6014, Australia
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Genome-Wide Identification and Analysis of the Polycomb Group Family in Medicago truncatula. Int J Mol Sci 2021; 22:ijms22147537. [PMID: 34299158 PMCID: PMC8303337 DOI: 10.3390/ijms22147537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/01/2021] [Accepted: 07/12/2021] [Indexed: 12/20/2022] Open
Abstract
Polycomb group (PcG) proteins, which are important epigenetic regulators, play essential roles in the regulatory networks involved in plant growth, development, and environmental stress responses. Currently, as far as we know, no comprehensive and systematic study has been carried out on the PcG family in Medicago truncatula. In the present study, we identified 64 PcG genes with distinct gene structures from the M. truncatula genome. All of the PcG genes were distributed unevenly over eight chromosomes, of which 26 genes underwent gene duplication. The prediction of protein interaction network indicated that 34 M. truncatula PcG proteins exhibited protein-protein interactions, and MtMSI1;4 and MtVRN2 had the largest number of protein-protein interactions. Based on phylogenetic analysis, we divided 375 PcG proteins from 27 species into three groups and nine subgroups. Group I and Group III were composed of five components from the PRC1 complex, and Group II was composed of four components from the PRC2 complex. Additionally, we found that seven PcG proteins in M. truncatula were closely related to the corresponding proteins of Cicer arietinum. Syntenic analysis revealed that PcG proteins had evolved more conservatively in dicots than in monocots. M. truncatula had the most collinearity relationships with Glycine max (36 genes), while collinearity with three monocots was rare (eight genes). The analysis of various types of expression data suggested that PcG genes were involved in the regulation and response process of M. truncatula in multiple developmental stages, in different tissues, and for various environmental stimuli. Meanwhile, many differentially expressed genes (DEGs) were identified in the RNA-seq data, which had potential research value in further studies on gene function verification. These findings provide novel and detailed information on the M. truncatula PcG family, and in the future it would be helpful to carry out related research on the PcG family in other legumes.
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Cheng X, Li G, Krom N, Tang Y, Wen J. Genetic regulation of flowering time and inflorescence architecture by MtFDa and MtFTa1 in Medicago truncatula. PLANT PHYSIOLOGY 2021; 185:161-178. [PMID: 33631796 PMCID: PMC8133602 DOI: 10.1093/plphys/kiaa005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/11/2020] [Indexed: 05/29/2023]
Abstract
Regulation of floral transition and inflorescence development is crucial for plant reproductive success. FLOWERING LOCUS T (FT) is one of the central players in the flowering genetic regulatory network, whereas FLOWERING LOCUS D (FD), an interactor of FT and TERMINAL FLOWER 1 (TFL1), plays significant roles in both floral transition and inflorescence development. Here we show the genetic regulatory networks of floral transition and inflorescence development in Medicago truncatula by characterizing MtFTa1 and MtFDa and their genetic interactions with key inflorescence meristem (IM) regulators. Both MtFTa1 and MtFDa promote flowering; the double mutant mtfda mtfta1 does not proceed to floral transition. RNAseq analysis reveals that a broad range of genes involved in flowering regulation and flower development are up- or downregulated by MtFTa1 and/or MtFDa mutations. Furthermore, mutation of MtFDa also affects the inflorescence architecture. Genetic analyses of MtFDa, MtFTa1, MtTFL1, and MtFULc show that MtFDa is epistatic to MtFULc and MtTFL1 in controlling IM identity. Our results demonstrate that MtFTa1 and MtFDa are major flowering regulators in M. truncatula, and MtFDa is essential both in floral transition and secondary inflorescence development. The study will advance our understanding of the genetic regulation of flowering time and inflorescence development in legumes.
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Affiliation(s)
- Xiaofei Cheng
- Noble Research Institute, Ardmore, Oklahoma 73401, USA
| | - Guifen Li
- Noble Research Institute, Ardmore, Oklahoma 73401, USA
| | - Nick Krom
- Noble Research Institute, Ardmore, Oklahoma 73401, USA
| | - Yuhong Tang
- Noble Research Institute, Ardmore, Oklahoma 73401, USA
| | - Jiangqi Wen
- Noble Research Institute, Ardmore, Oklahoma 73401, USA
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13
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Su YH, Tang LP, Zhao XY, Zhang XS. Plant cell totipotency: Insights into cellular reprogramming. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:228-243. [PMID: 32437079 DOI: 10.1111/jipb.12972] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Plant cells have a powerful capacity in their propagation to adapt to environmental change, given that a single plant cell can give rise to a whole plant via somatic embryogenesis without the need for fertilization. The reprogramming of somatic cells into totipotent cells is a critical step in somatic embryogenesis. This process can be induced by stimuli such as plant hormones, transcriptional regulators and stress. Here, we review current knowledge on how the identity of totipotent cells is determined and the stimuli required for reprogramming of somatic cells into totipotent cells. We highlight key molecular regulators and associated networks that control cell fate transition from somatic to totipotent cells. Finally, we pose several outstanding questions that should be addressed to enhance our understanding of the mechanisms underlying plant cell totipotency.
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Affiliation(s)
- Ying Hua Su
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Li Ping Tang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Xiang Yu Zhao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Xian Sheng Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
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14
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Labandera A, Tedds HM, Bailey M, Sprigg C, Etherington RD, Akintewe O, Kalleechurn G, Holdsworth MJ, Gibbs DJ. The PRT6 N-degron pathway restricts VERNALIZATION 2 to endogenous hypoxic niches to modulate plant development. THE NEW PHYTOLOGIST 2021; 229:126-139. [PMID: 32043277 PMCID: PMC7754370 DOI: 10.1111/nph.16477] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 02/04/2020] [Indexed: 05/20/2023]
Abstract
VERNALIZATION2 (VRN2), an angiosperm-specific subunit of the polycomb repressive complex 2 (PRC2), is an oxygen (O2 )-regulated target of the PCO branch of the PRT6 N-degron pathway of ubiquitin-mediated proteolysis. How this post-translational regulation coordinates VRN2 activity remains to be fully established. Here we use Arabidopsis thaliana ecotypes, mutants and transgenic lines to determine how control of VRN2 stability contributes to its functions during plant development. VRN2 localizes to endogenous hypoxic regions in aerial and root tissues. In the shoot apex, VRN2 differentially modulates flowering time dependent on photoperiod, whilst its presence in lateral root primordia and the root apical meristem negatively regulates root system architecture. Ectopic accumulation of VRN2 does not enhance its effects on flowering, but does potentiate its repressive effects on root growth. In late-flowering vernalization-dependent ecotypes, VRN2 is only active outside meristems when its proteolysis is inhibited in response to cold exposure, as its function requires concomitant cold-triggered increases in other PRC2 subunits and cofactors. We conclude that the O2 -sensitive N-degron of VRN2 has a dual function, confining VRN2 to meristems and primordia, where it has specific developmental roles, whilst also permitting broad accumulation outside of meristems in response to environmental cues, leading to other functions.
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Affiliation(s)
| | - Hannah M. Tedds
- School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
| | - Mark Bailey
- School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
| | - Colleen Sprigg
- School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
| | | | | | | | | | - Daniel J. Gibbs
- School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
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15
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Jaudal M, Wen J, Mysore KS, Putterill J. Medicago PHYA promotes flowering, primary stem elongation and expression of flowering time genes in long days. BMC PLANT BIOLOGY 2020; 20:329. [PMID: 32652925 PMCID: PMC7353751 DOI: 10.1186/s12870-020-02540-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/05/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND Flowering time is an important trait for productivity in legumes, which include many food and fodder plants. Medicago truncatula (Medicago) is a model temperate legume used to study flowering time pathways. Like Arabidopsis thaliana (Arabidopsis), its flowering is promoted by extended periods of cold (vernalization, V), followed by warm long day (LD) photoperiods. However, Arabidopsis flowering-time genes such as the FLOWERING LOCUS C (FLC)/ MADS AFFECTING FLOWERING (MAF) clade are missing and CONSTANS-LIKE (CO-LIKE) genes do not appear to have a role in Medicago or Pisum sativum (pea). Another photoperiodic regulator, the red/far red photoreceptor PHYTOCHROME A (PHYA), promotes Arabidopsis flowering by stabilizing the CO protein in LD. Interestingly, despite the absence of CO-LIKE function in pea, PsPHYA plays a key role in promoting LD photoperiodic flowering and plant architecture. Medicago has one homolog of PHYA, MtPHYA, but its function is not known. RESULTS Genetic analysis of two MtPHYA Tnt1 insertion mutant alleles indicates that MtPHYA has an important role in promoting Medicago flowering and primary stem elongation in VLD and LD and in perception of far-red wavelengths in seedlings. MtPHYA positively regulates the expression of MtE1-like (MtE1L), a homologue of an important legume-specific flowering time gene, E1 in soybean and other Medicago LD-regulated flowering-time gene homologues, including the three FLOWERING LOCUS T-LIKE (FT-LIKE) genes, MtFTa1, MtFTb1 and MtFTb2 and the two FRUITFULL-LIKE (FUL-LIKE) genes MtFULa and MtFULb. MtPHYA also modulates the expression of the circadian clock genes, GIGANTEA (GI) and TIMING OF CAB EXPRESSION 1a (TOC1a). Genetic analyses indicate that Mtphya-1 Mte1l double mutants flowered at the same time as the single mutants. However, Mtphya-1 Mtfta1 double mutants had a weak additive effect in delaying flowering and in reduction of primary axis lengths beyond what was conferred by either of the single mutants. CONCLUSION MtPHYA has an important role in LD photoperiodic control of flowering, plant architecture and seedling de-etiolation under far-red wavelengths in Medicago. It promotes the expression of LD-induced flowering time genes and modulates clock-related genes. In addition to MtFTa1, MtPHYA likely regulates other targets during LD floral induction in Medicago.
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Affiliation(s)
- Mauren Jaudal
- The Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand.
| | - Jiangqi Wen
- Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK73401, USA
| | | | - Joanna Putterill
- The Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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Rani A, Devi P, Jha UC, Sharma KD, Siddique KHM, Nayyar H. Developing Climate-Resilient Chickpea Involving Physiological and Molecular Approaches With a Focus on Temperature and Drought Stresses. FRONTIERS IN PLANT SCIENCE 2020; 10:1759. [PMID: 32161601 PMCID: PMC7052492 DOI: 10.3389/fpls.2019.01759] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/16/2019] [Indexed: 05/19/2023]
Abstract
Chickpea is one of the most economically important food legumes, and a significant source of proteins. It is cultivated in more than 50 countries across Asia, Africa, Europe, Australia, North America, and South America. Chickpea production is limited by various abiotic stresses (cold, heat, drought, salt, etc.). Being a winter-season crop in northern south Asia and some parts of the Australia, chickpea faces low-temperature stress (0-15°C) during the reproductive stage that causes substantial loss of flowers, and thus pods, to inhibit its yield potential by 30-40%. The winter-sown chickpea in the Mediterranean, however, faces cold stress at vegetative stage. In late-sown environments, chickpea faces high-temperature stress during reproductive and pod filling stages, causing considerable yield losses. Both the low and the high temperatures reduce pollen viability, pollen germination on the stigma, and pollen tube growth resulting in poor pod set. Chickpea also experiences drought stress at various growth stages; terminal drought, along with heat stress at flowering and seed filling can reduce yields by 40-45%. In southern Australia and northern regions of south Asia, lack of chilling tolerance in cultivars delays flowering and pod set, and the crop is usually exposed to terminal drought. The incidences of temperature extremes (cold and heat) as well as inconsistent rainfall patterns are expected to increase in near future owing to climate change thereby necessitating the development of stress-tolerant and climate-resilient chickpea cultivars having region specific traits, which perform well under drought, heat, and/or low-temperature stress. Different approaches, such as genetic variability, genomic selection, molecular markers involving quantitative trait loci (QTLs), whole genome sequencing, and transcriptomics analysis have been exploited to improve chickpea production in extreme environments. Biotechnological tools have broadened our understanding of genetic basis as well as plants' responses to abiotic stresses in chickpea, and have opened opportunities to develop stress tolerant chickpea.
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Affiliation(s)
- Anju Rani
- Department of Botany, Panjab University, Chandigarh, India
| | - Poonam Devi
- Department of Botany, Panjab University, Chandigarh, India
| | - Uday Chand Jha
- Department of Crop Improvement Division, Indian Institute of Pulses Research, Kanpur, India
| | - Kamal Dev Sharma
- Department of Agricultural Biotechnology, Himachal Pradesh Agricultural University, Palampur, India
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Harsh Nayyar
- Department of Botany, Panjab University, Chandigarh, India
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17
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Ortega R, Hecht VFG, Freeman JS, Rubio J, Carrasquilla-Garcia N, Mir RR, Penmetsa RV, Cook DR, Millan T, Weller JL. Altered Expression of an FT Cluster Underlies a Major Locus Controlling Domestication-Related Changes to Chickpea Phenology and Growth Habit. FRONTIERS IN PLANT SCIENCE 2019; 10:824. [PMID: 31333691 PMCID: PMC6616154 DOI: 10.3389/fpls.2019.00824] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 06/07/2019] [Indexed: 05/20/2023]
Abstract
Flowering time is a key trait in breeding and crop evolution, due to its importance for adaptation to different environments and for yield. In the particular case of chickpea, selection for early phenology was essential for the successful transition of this species from a winter to a summer crop. Here, we used genetic and expression analyses in two different inbred populations to examine the genetic control of domestication-related differences in flowering time and growth habit between domesticated chickpea and its wild progenitor Cicer reticulatum. A single major quantitative trait locus for flowering time under short-day conditions [Days To Flower (DTF)3A] was mapped to a 59-gene interval on chromosome three containing a cluster of three FT genes, which collectively showed upregulated expression in domesticated relative to wild parent lines. An equally strong association with growth habit suggests a pleiotropic effect of the region on both traits. These results indicate the likely molecular explanation for the characteristic early flowering of domesticated chickpea, and the previously described growth habit locus Hg. More generally, they point to de-repression of this specific gene cluster as a conserved mechanism for achieving adaptive early phenology in temperate legumes.
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Affiliation(s)
- Raul Ortega
- School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
| | | | - Jules S. Freeman
- School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
- Scion, Rotorua, New Zealand
| | - Josefa Rubio
- E. Genomica y Biotecnologia, Instituto Andaluz de Investigación y Formación Agraria y Pesquera (IFAPA), Córdoba, Spain
| | | | - Reyazul Rouf Mir
- Department of Plant Pathology, University of California, Davis, Davis, CA, United States
- Division of Genetics and Plant Breeding, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar, India
| | - R. Varma Penmetsa
- Department of Plant Pathology, University of California, Davis, Davis, CA, United States
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
| | - Douglas R. Cook
- Department of Plant Pathology, University of California, Davis, Davis, CA, United States
| | - Teresa Millan
- Department of Genetics ETSIAM, University of Córdoba, Córdoba, Spain
| | - James L. Weller
- School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
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18
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Jaudal M, Zhang L, Che C, Li G, Tang Y, Wen J, Mysore KS, Putterill J. A SOC1-like gene MtSOC1a promotes flowering and primary stem elongation in Medicago. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4867-4880. [PMID: 30295903 PMCID: PMC6137972 DOI: 10.1093/jxb/ery284] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/10/2018] [Indexed: 05/19/2023]
Abstract
Medicago flowering, like that of Arabidopsis, is promoted by vernalization and long days, but alternative mechanisms are predicted because Medicago lacks the key regulators CO and FLC. Three Medicago SOC1-like genes, including MtSOC1a, were previously implicated in flowering control, but no legume soc1 mutants with altered flowering were reported. Here, reverse transciption-quantitative PCR (RT-qPCR) indicated that the timing and magnitude of MtSOC1a expression was regulated by the flowering promoter FTa1, while in situ hybridization indicated that MtSOC1a expression increased in the shoot apical meristem during the floral transition. A Mtsoc1a mutant showed delayed flowering and short primary stems. Overexpression of MtSOC1a partially rescued the flowering of Mtsoc1a, but caused a dramatic increase in primary stem height, well before the transition to flowering. Internode cell length correlated with stem height, indicating that MtSOC1a promotes cell elongation in the primary stem. However, application of gibberellin (GA3) caused stem elongation in both the wild type and Mtsoc1a, indicating that the mutant was not defective in gibberellin responsiveness. These results indicate that MtSOC1a may function as a floral integrator gene and promotes primary stem elongation. Overall, this study suggests that apart from some conservation with the Arabidopsis flowering network, MtSOC1a has a novel role in regulating aspects of shoot architecture.
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Affiliation(s)
- Mauren Jaudal
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Lulu Zhang
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Chong Che
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Guifen Li
- Noble Research Institute, LLC, Ardmore, OK, USA
| | - Yuhong Tang
- Noble Research Institute, LLC, Ardmore, OK, USA
| | - Jiangqi Wen
- Noble Research Institute, LLC, Ardmore, OK, USA
| | | | - Joanna Putterill
- Flowering Lab, School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Functional Genomics and Flowering Time in Medicago truncatula: An Overview. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2018; 1822:261-271. [PMID: 30043309 DOI: 10.1007/978-1-4939-8633-0_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Flowering time is an important trait that influences adaptation and yield in many crop legumes. Both the inherent earliness of flowering and the degree to which it is responsive to environmental factors determine both the eco-geographic range across which crops can be successfully grown and the seasonal cycles most suitable for production. This chapter will provide a brief review of studies investigating the genetic control of flowering time in Medicago truncatula.
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20
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Vachon G, Engelhorn J, Carles CC. Interactions between transcription factors and chromatin regulators in the control of flower development. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2461-2471. [PMID: 29506187 DOI: 10.1093/jxb/ery079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/22/2018] [Indexed: 06/08/2023]
Abstract
Chromatin modifiers and remodelers are involved in generating dynamic changes at the chromatin, which allow differential and specific readouts of the genome. While genetic evidence indicates that several chromatin factors play a key role in controlling basic developmental programs for inflorescence and flower morphogenesis, it remained unknown until recently how they exert their specificity toward gene expression, both temporally and spatially. An emerging topic is the recruitment or eviction of chromatin factors through the activity of sequence-specific DNA-binding domains, present in the chromatin factors themselves or in partnering transcription factors. Here we summarize recent progress that has been made in this regard in the model plant Arabidopsis thaliana. We further outline the different possible modes through which chromatin complexes specifically target genes involved in flower development.
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Affiliation(s)
- Gilles Vachon
- LPCV, CNRS, CEA, INRA, Université Grenoble Alpes, BIG, Grenoble, France
| | - Julia Engelhorn
- LPCV, CNRS, CEA, INRA, Université Grenoble Alpes, BIG, Grenoble, France
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21
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Fudge JB, Lee RH, Laurie RE, Mysore KS, Wen J, Weller JL, Macknight RC. Medicago truncatula SOC1 Genes Are Up-regulated by Environmental Cues That Promote Flowering. FRONTIERS IN PLANT SCIENCE 2018; 9:496. [PMID: 29755488 PMCID: PMC5934494 DOI: 10.3389/fpls.2018.00496] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 04/03/2018] [Indexed: 05/20/2023]
Abstract
Like Arabidopsis thaliana, the flowering of the legume Medicago truncatula is promoted by long day (LD) photoperiod and vernalization. However, there are differences in the molecular mechanisms involved, with orthologs of two key Arabidopsis thaliana regulators, FLOWERING LOCUS C (FLC) and CONSTANS (CO), being absent or not having a role in flowering time function in Medicago. In Arabidopsis, the MADS-box transcription factor gene, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (AtSOC1), plays a key role in integrating the photoperiodic and vernalization pathways. In this study, we set out to investigate whether the Medicago SOC1 genes play a role in regulating flowering time. Three Medicago SOC1 genes were identified and characterized (MtSOC1a-MtSOC1c). All three MtSOC1 genes, when heterologously expressed, were able to promote earlier flowering of the late-flowering Arabidopsis soc1-2 mutant. The three MtSOC1 genes have different patterns of expression. However, consistent with a potential role in flowering time regulation, all three MtSOC1 genes are expressed in the shoot apex and are up-regulated in the shoot apex of plants in response to LD photoperiods and vernalization. The up-regulation of MtSOC1 genes was reduced in Medicago fta1-1 mutants, indicating that they are downstream of MtFTa1. Insertion mutant alleles of Medicago soc1b do not flower late, suggestive of functional redundancy among Medicago SOC1 genes in promoting flowering.
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Affiliation(s)
- Jared B. Fudge
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Robyn H. Lee
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Rebecca E. Laurie
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Kirankumar S. Mysore
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, OK, United States
| | - Jiangqi Wen
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, OK, United States
| | - James L. Weller
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Richard C. Macknight
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- New Zealand Institute for Plant and Food Research Ltd., University of Otago, Dunedin, New Zealand
- *Correspondence: Richard C. Macknight,
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