Open AccessDistinct regulatory role for RFL , the rice LFY homolog, in determining flowering time and plant architecture
Author(s) -
Nagashree N Rao,
Kalika Prasad,
Puja Ravi Kumar,
Usha Vijayraghavan
Publication year - 2008
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0709059105
Subject(s) - meristem , biology , primordium , inflorescence , axillary bud , arabidopsis , leafy , arabidopsis thaliana , ectopic expression , botany , microbiology and biotechnology , silique , transcription factor , genetics , gene , shoot , mutant , in vitro , explant culture
Activity of axillary meristems dictates the architecture of both vegetative and reproductive parts of a plant. InArabidopsis thaliana , a model eudicot species, the transcription factor LFY confers a floral fate to new meristems arising from the periphery of the reproductive shoot apex. Diverse orthologousLFY genes regulate vegetative-to-reproductive phase transition when expressed inArabidopsis , a property not shared byRFL , the homolog in the agronomically important grass, rice. We have characterizedRFL by knockdown of its expression and by its ectopic overexpression in transgenic rice. We find that reduction inRFL expression causes a dramatic delay in transition to flowering, with the extreme phenotype being no flowering. Conversely,RFL overexpression triggers precocious flowering. In these transgenics, the expression levels of known flowering time genes revealRFL as a regulator ofOsSOC1 (OsMADS50 ), an activator of flowering. Aside from facilitating a transition of the main growth axis to an inflorescence meristem,RFL expression status affects vegetative axillary meristems and therefore regulates tillering. The unique spatially and temporally regulatedRFL expression during the development of vegetative axillary bud (tiller) primordia and inflorescence branch primordia is therefore required to produce tillers and panicle branches, respectively. Our data provide mechanistic insights into a unique role forRFL in determining the typical rice plant architecture by regulating distinct downstream pathways. These results offer a means to alter rice flowering time and plant architecture by manipulating RFL-mediated pathways.