文档介绍：The Plant Journal (2015) 82, 256–266 doi:
Hd3a promotes lateral branching in rice
Hiroyuki Tsuji1,*, Chika Tachibana1, Shojiro Tamaki1, Ken-ichiro Taoka1, Junko Kyozuka2 and Ko Shimamoto1,†
1Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology,
8916–5 Takayama, Ikoma, Nara 630–0192, Japan, and
2Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo, Tokyo 113–8657, Japan
Received 9 December 2012; revised 16 February 2015; accepted 23 February 2015; published online 3 March 2015.
*For correspondence (e-mail ******@).
†Ko Shimamoto passed away on 28th September 2013.
SUMMARY
Accumulating evidence indicates that the FLOWERING LOCUS T (FT) protein is the mobile floral signal
known as florigen. A rice FT homolog, Heading date 3a (Hd3a), is transported from the phloem to shoot api-
cal cells, where it interacts with 14–3–3 proteins and transcription factor OsFD1 to form a florigen activation
complex (FAC) that activates a rice homolog of the floral identity gene APETALA1. Recent studies showed
that florigen has roles in plant development beyond flowering; however, the exact nature of these roles is
not well understood. It is not clear whether FT is transported to organs outside the shoot apex, and
whether FAC formation is required for processes other than flowering. We show here that the Hd3a protein
accumulates in axillary meristems to promote branching, and that FAC formation is required. Analysis of
transgenic plants revealed that Hd3a promotes branching through lateral bud outgrowth. Hd3a protein pro-
duced in the phloem reached the axillary meristem in the lateral bud, and its transport was required for pro-
motion of branching. Moreover, mutant Hd3a proteins defective in FAC formation