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Hd3a promotes lateral branching in rice
Author(s) -
Tsuji Hiroyuki,
Tachibana Chika,
Tamaki Shojiro,
Taoka Kenichiro,
Kyozuka Junko,
Shimamoto Ko
Publication year - 2015
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12811
Subject(s) - biology , axillary bud , meristem , strigolactone , microbiology and biotechnology , phloem , botany , arabidopsis , lateral shoot , mutant , branching (polymer chemistry) , transcription factor , shoot , gene , genetics , tissue culture , materials science , in vitro , composite material
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 apical cells, where it interacts with 14–3–3 proteins and transcription factor Os FD 1 to form a florigen activation complex ( FAC ) that activates a rice homolog of the floral identity gene APETALA 1 . 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 produced in the phloem reached the axillary meristem in the lateral bud, and its transport was required for promotion of branching. Moreover, mutant Hd3a proteins defective in FAC formation but competent with respect to transport did not promote branching. Finally, we show that Hd3a promotes branching independently from strigolactone and FC 1, a transcription factor that inhibits branching in rice. Together, these results suggest that Hd3a functions as a mobile signal for branching in rice.