J Integr Plant Biol ›› 2011, Vol. 53 ›› Issue (11): 869-878.DOI: 10.1111/j.1744-7909.2011.01075.x

Special Issue: Rice Genomics and Agriculture

• Plant-environmental Interactions • Previous Articles     Next Articles

Rice Homeobox Transcription Factor HOX1a Positively Regulates Gibberellin Responses by Directly Suppressing EL1

Bi-Qing Wen, Mei-Qing Xing, Hua Zhang, Cheng Dai and Hong-Wei Xue*   

  1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200032, China
  • Received:2011-07-12 Accepted:2011-09-14 Published:2011-09-21
  • About author:*Corresponding author Tel: +86 21 5492 4059; Fax: +86 21 5492 4059; E-mail: hwxue@sibs.ac.cn

Abstract:

Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox proteins have been identified. We here show that overexpression of rice homeobox gene HOX1a resulted in enhanced gibberellin (GA) response, indicating a positive effect of HOX1a in GA signaling. HOX1a is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOX1a suppresses the transcription of early flowering1 (EL1), a negative regulator of GA signaling, and further electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that HOX1a directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOX1a functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling.

 Wen BQ, Xing MQ, Zhang H, Dai C, Xue HW (2011) Rice homeobox transcription factor HOX1a positively regulates giberellin responses by directly suppressing EL1. J. Integr. Plant Biol. 53(11), 869–878.

Key words: EL1, giberellin, giberellin signaling, HOX1a, homeobox

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