title: Overexpression of Medicago SVP genes causes floral defects and delayed flowering in Arabidopsis but only affects floral development in Medicago.
abstract: The MADS-domain transcription factor SHORT VEGETATIVE PHASE plays a key role as a repressor of the transition to flowering and as a regulator of early floral development in Arabidopsis thaliana (Arabidopsis). However, no flowering-time repressors have been functionally identified in the model legume Medicago truncatula (Medicago). In this study, phylogenetic analysis of two closely-related MtSVP-like sequences, MtSVP1 and MtSVP2, showed that their predicted proteins clustered together within the eudicot SVP clade. To determine if the MtSVP-like genes have a role in flowering, they were functionally characterized in Medicago and Arabidopsis. Transcripts of both MtSVP genes were abundant and broadly expressed in vegetative tissues but were detected at much lower levels in flowers in Medicago. Over-expression of the MtSVP genes in Arabidopsis resulted in delayed flowering and flowers with many abnormal phenotypes such as leafy sepals, changes to floral organ number and longer pedicels than the wild type. By contrast, in transgenic Medicago, over-expression of MtSVP1 resulted in alterations to flower development, but did not alter flowering time, suggesting that MtSVP1 may not function to repress the transition to flowering in Medicago.
authors.affiliation: Flowering Laboratory, School of Biological Sciences, University of Auckland, Private Bag, Auckland 92019, New Zealand.
authors.forename: Mauren
authors.initials: M
authors.lastname: Jaudal
authors.forename: Jacob
authors.initials: J
authors.lastname: Monash
authors.forename: Lulu
authors.initials: L
authors.lastname: Zhang
authors.forename: Jiangqi
authors.initials: J
authors.lastname: Wen
authors.forename: Kirankumar S
authors.initials: KS
authors.lastname: Mysore
authors.forename: Richard
authors.initials: R
authors.lastname: Macknight
authors.forename: Joanna
authors.initials: J
authors.lastname: Putterill
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology*; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D029902:Medicago / Q000235:genetics* / Q000254:growth & development*; D016254:Mutagenesis, Insertional / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D060888:Real-Time Polymerase Chain Reaction; D018626:Retroelements / Q000235:genetics; D013997:Time Factors
chemical_list: D010940:Plant Proteins; D018626:Retroelements
keywords: Arabidopsis; MADS; Medicago; SVP.; flowering; legume