525 / 2019-03-04 19:57:38

MCTP-SNARE Complex-Mediated Regulation of Florigen Transport in Arabidopsis

MCTP, SNARE, FT, Flowering

全体主题 > Development

Multiple flowering pathways in Arabidopsis thaliana converge on the transcriptional regulation of FLOWERING LOCUS T (FT), which encodes a mobile floral stimulus that moves from leaves to the shoot apex. Despite the progress in understanding FT movement, the mechanisms underlying its transport along the ER-plasmalemma pathway in phloem companion cells remain largely unclear. Here, we show that a plasma membrane (PM)-resident syntaxin-like Q-SNARE, SYNTAXIN OF PLANTS 121 (SYP121), interacts with QUIRKY (QKY), a member of the family of multiple C2 domain and transmembrane region proteins (MCTPs), to mediate FT transport in Arabidopsis. In coordination, QKY and SYP121 regulate FT movement to the plasmalemma through the endosomal trafficking pathway and are required for FT export from companion cells to sieve elements, thus affecting FT transport through the phloem to the shoot apical meristem. These findings suggest that MCTP-SNARE complex-mediated endosomal trafficking is essential for florigen export from phloem companion cells to induce flowering.