Read at : Google Alert – drought
http://www.plantcell.org/cgi/content/short/tpc.108.058263v1
Activated Expression of an Arabidopsis HD-START Protein Confers Drought Tolerance with Improved Root System and Reduced Stomatal Density
Hong Yu 1, Xi Chen 1, Yuan-Yuan Hong 1, Yao Wang 1, Ping Xu 1, Sheng-Dong Ke 1, Hai-Yan Liu 1, Jian-Kang Zhu 2, David J. Olive 3, and Cheng-Bin Xiang 1*
1 School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People’s Republic of China
2 Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521
3 Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
* To whom correspondence should be addressed. E-mail: xiangcb@ustc.edu.cn<!–
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Drought is one of the most important environmental constraints limiting plant growth and agricultural productivity. To understand the underlying mechanism of drought tolerance and to identify genes for improving this important trait, we conducted a gain-of-function genetic screen for improved drought tolerance in Arabidopsis thaliana. One mutant with improved drought tolerance was isolated and designated as enhanced drought tolerance1. The mutant has a more extensive root system than the wild type, with deeper roots and more lateral roots, and shows a reduced leaf stomatal density. The mutant had higher levels of abscisic acid and Pro than the wild type and demonstrated an increased resistance to oxidative stress and high levels of superoxide dismutase. Molecular genetic analysis and recapitulation experiments showed that the enhanced drought tolerance is caused by the activated expression of a T-DNA tagged gene that encodes a putative homeodomain-START transcription factor. Moreover, overexpressing the cDNA of the transcription factor in transgenic tobacco also conferred drought tolerance associated with improved root architecture and reduced leaf stomatal density. Therefore, we have revealed functions of the homeodomain-START factor that were gained upon altering its expression pattern by activation tagging and provide a key regulator that may be used to improve drought tolerance in plants.
