title: Flowering time modulation by a vacuolar SNARE via FLOWERING LOCUS C in Arabidopsis thaliana.
abstract: The transition of plant growth from vegetative to reproductive phases is one of the most important and dramatic events during the plant life cycle. In Arabidopsis thaliana, flowering promotion involves at least four genetically defined regulatory pathways, including the photoperiod-dependent, vernalization-dependent, gibberellin-dependent, and autonomous promotion pathways. Among these regulatory pathways, the vernalization-dependent and autonomous pathways are integrated by the expression of FLOWERING LOCUS C (FLC), a negative regulator of flowering; however, the upstream regulation of this locus has not been fully understood. The SYP22 gene encodes a vacuolar SNARE protein that acts in vacuolar and endocytic trafficking pathways. Loss of SYP22 function was reported to lead to late flowering in A. thaliana plants, but the mechanism has remained completely unknown. In this study, we demonstrated that the late flowering phenotype of syp22 was due to elevated expression of FLC caused by impairment of the autonomous pathway. In addition, we investigated the DOC1/BIG pathway, which is also suggested to regulate vacuolar/endosomal trafficking. We found that elevated levels of FLC transcripts accumulated in the doc1-1 mutant, and that syp22 phenotypes were exaggerated with a double syp22 doc1-1 mutation. We further demonstrated that the elevated expression of FLC was suppressed by ara6-1, a mutation in the gene encoding plant-unique Rab GTPase involved in endosomal trafficking. Our results indicated that vacuolar and/or endocytic trafficking is involved in the FLC regulation of flowering time in A. thaliana.
authors: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors: Kazuo
authors: K
authors: Ebine
authors: Tomohiro
authors: T
authors: Uemura
authors: Akihiko
authors: A
authors: Nakano
authors: Takashi
authors: T
authors: Ueda
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000235:genetics; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D035264:Flowers / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D050765:Qa-SNARE Proteins / Q000378:metabolism*; D013997:Time Factors; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C434262:BIG protein, Arabidopsis; D002148:Calmodulin-Binding Proteins; C418902:At5g10140 protein, Arabidopsis; D005875:Gibberellins; D026161:MADS Domain Proteins; D050765:Qa-SNARE Proteins; C108430:Vam3 protein, Arabidopsis; C007842:gibberellic acid; C436706:Ara6 protein, Arabidopsis; D020691:rab GTP-Binding Proteins