Molecular Plant Advance Access originally published online on October 12, 2007
Molecular Plant 2008 1(1):42-57; doi:10.1093/mp/ssm004
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© The Author 2007. Published by Oxford University Press on behalf of CSPP and IPPE, SIBS, CAS.
Role of Arabidopsis RAP2.4 in Regulating Light- and Ethylene-Mediated Developmental Processes and Drought Stress Tolerance
Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853, USA
1 To whom correspondence should be addressed. E-mail hw75{at}cornell.edu, tel. 1–607–254–7476; fax 1–607–254–1242.
Light and the plant hormone ethylene regulate many aspects of plant growth and development in an overlapping and interdependent fashion. Little is known regarding how their signal transduction pathways cross-talk to regulate plant development in a coordinated manner. Here, we report functional characterization of an AP2/DREB-type transcription factor, Arabidopsis RAP2.4, in mediating light and ethylene signaling. Expression of the RAP2.4 gene is down-regulated by light but up-regulated by salt and drought stresses. RAP2.4 protein is constitutively targeted to the nucleus and it can bind to both the ethylene-responsive GCC-box and the dehydration-responsive element (DRE). We show that RAP2.4 protein possesses an intrinsic transcriptional activation activity in yeast cells and that it can activate a reporter gene driven by the DRE cis-element in Arabidopsis protoplasts. Overexpression of RAP2.4 or mutation in RAP2.4 cause altered expression of representative light-, ethylene-, and drought-responsive genes. Although no salient phenotype was observed with a rap2.4 loss-of-function mutant, constitutive overexpression of RAP2.4 results in defects in multiple developmental processes regulated by light and ethylene, including hypocotyl elongation and gravitropism, apical hook formation and cotyledon expansion, flowering time, root elongation, root hair formation, and drought tolerance. Based on these observations, we propose that RAP2.4 acts at or downstream of a converging point of light and ethylene signaling pathways to coordinately regulate multiple developmental processes and stress responses.
Key Words: Arabidopsis RAP2.4 transcription factor light signaling ethylene response drought tolerance
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Compiled by, F. Tooke, T. Chiurugwi, and N. Battey Flowering Newsletter bibliography for 2008 J. Exp. Bot., June 23, 2009; (2009) erp154v1. [Full Text] [PDF] |
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