title: FLOWERING LOCUS T has higher protein mobility than TWIN SISTER OF FT.
abstract: In plants, successful reproduction requires the proper timing of flowering under changing environmental conditions. Arabidopsis FLOWERING LOCUS T (FT), which encodes a proposed phloem-mobile florigen, has a close homologue, TWIN SISTER OF FT (TSF). During the vegetative phase, TSF shows high levels of expression in the hypocotyl before FT induction, but the tsf mutation does not have an apparent flowering-time phenotype on its own under long-day conditions. This study compared the protein mobility of FT and TSF. With TSF-overexpressing plants as the rootstock, the flowering time of ft tsf scion plants was only slightly accelerated. Previous work has shown that FT is graft-transmissible; by contrast, this study did not detect movement of TSF from the roots into the shoot of the scion plants. This study used plants overexpressing FT/TSF chimeric proteins to map a region responsible for FT movement. A chimeric TSF with region II of FT (L28 to G98) expressed in the rootstock caused early flowering in ft tsf scion plants; movement of the chimeric protein from the rootstocks into the shoot apical region of the ft tsf scion plants was also detected. Misexpression of TSF in the leaf under the control of the FT promoter or grafting of 35S::TSF cotyledons accelerated flowering of ft-10 plants. FT was more stable than TSF. Taking these results together, we propose that protein mobility of FT is higher than that of TSF, possibly due to a protein domain that confers mobility and/or protein stability.
authors.affiliation: Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 136-701, South Korea.
authors.forename: Suhyun
authors.initials: S
authors.lastname: Jin
authors.affiliation: Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 136-701, South Korea.
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Jung
authors.affiliation: Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 136-701, South Korea.
authors.forename: Kyung Sook
authors.initials: KS
authors.lastname: Chung
authors.affiliation: Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 136-701, South Korea.
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 136-701, South Korea jahn@korea.ac.kr.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Ahn
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D049488:Phosphatidylethanolamine Binding Protein / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction
chemical_list: D029681:Arabidopsis Proteins; C418905:FT protein, Arabidopsis; D049488:Phosphatidylethanolamine Binding Protein; C500577:TSF protein, Arabidopsis
keywords: Arabidopsis thaliana; FLOWERING LOCUS T (FT); Flowering time; TWIN SISTER OF FT (TSF).; long-distance signalling; micrografting