Distinct regulatory role for RFL, the rice LFY homolog, in determining flowering time and plant architecture

Rao, Nagashree N and Prasad, Kalika and Ravi Kumar, Puja and Vijayraghavan, Usha (2008) Distinct regulatory role for RFL, the rice LFY homolog, in determining flowering time and plant architecture. In: Proceedings of the National Academy of Sciences of the United States of America (PNAS), 105 (9). pp. 3646-3651.

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Abstract

Activity of axillary meristems dictates the architecture of both vegetative and reproductive parts of a plant. In Arabidopsis 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 orthologous LFY genes regulate vegetative-to-reproductive phase transition when expressed in Arabidopsis, a property not shared by RFL, the homolog in the agronomically important grass, rice. We have characterized RFL by knockdown of its expression and by its ectopic overexpression in transgenic rice. We find that reduction in RFL 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 reveal RFL as a regulator of OsSOC1 (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 regulated RFL 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 for RFL 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.

Item Type:	Journal Article
Publication:	Proceedings of the National Academy of Sciences of the United States of America (PNAS)
Publisher:	National Academy of Sciences
Additional Information:	Copyright of this article belongs to National Academy of Sciences.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	01 Apr 2008
Last Modified:	19 Sep 2010 04:44
URI:	http://eprints.iisc.ac.in/id/eprint/13622

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