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Floral homeotic genes are targets of gibberellin signaling in flower development

Yu, Hao and Ito, Toshiro and Zhao, Yuanxiang and Peng, Jinrong and Kumar, Prakash and Meyerowitz, Elliot M. (2004) Floral homeotic genes are targets of gibberellin signaling in flower development. Proceedings of the National Academy of Sciences of the United States of America, 101 (20). pp. 7827-7832. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:YUHpnas04

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Abstract

Gibberellins (GAS) are a class of plant hormones involved in the regulation of flower development in Arabidopsis. The GA-deficient ga1-3 mutant shows retarded growth of all floral organs, especially abortive stamen development that results in complete male sterility. Until now, it has not been clear how GA regulates the late-stage development of floral organs after the establishment of their identities within floral meristems. Various combinations of null mutations of DELLA proteins can gradually rescue floral defects in ga1-3. In particular, the synergistic effect of rga-t2 and rgl2-1 can substantially restore flower development in ga1-3. We find that the transcript levels of floral homeotic genes APETALA3 (AP3), PISTILLATA (PO, and AGAMOUS (AG) are immediately upregulated in young flowers of ga1-3 upon GA treatment. Using a steroid-inducible activation of RGA, we further demonstrated that these floral homeotic genes are transcriptionally repressed by RGA activity in young flowers whereas the expression of LEAFY (LFY) and APETALA1 (AP1) is not substantially affected. In addition, we observed the partial rescue of floral defects in ga1-3 by overexpression of AG. Our results indicate that GA promotes the expression of floral homeotic genes by antagonizing the effects of DELLA proteins, thereby allowing continued flower development.


Item Type:Article
Additional Information:Copyright © 2004 by the National Academy of Sciences. Contributed by Elliot M. Meyerowitz, April 3, 2004. We thank Dr. Nick Harberd and Dr. Tai-Ping Sun for helpful comments and critical reading of the manuscript. This work was funded by National Institutes of Health Grant GM45697 (to E.M.M). H.Y. was supported in part by an overseas postdoctoral fellowship from the National University of Singapore. Supplementary material http://www.pubmedcentral.gov/articlerender.fcgi?artid=419691#supplementary-material-sec
Subject Keywords:ARABIDOPSIS-THALIANA, MERISTEM IDENTITY, CELL FATE, APETALA1, RGA, EXPRESSION, REGULATOR, PATHWAY, ENCODES, LEAFY
Record Number:CaltechAUTHORS:YUHpnas04
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:YUHpnas04
Alternative URL:http://dx.doi.org/10.1073/pnas.0402377101
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:923
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Nov 2005
Last Modified:26 Dec 2012 08:42

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