Submitted to: Plant Molecular Biology Reporter
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/21/2008
Publication Date: 12/2/2008
Citation: Hall, J.D., Cobb, J., Iqbal, M., Abidali, M., Liu, Z., Mount, D.W. 2008. UVH6, a plant homolog of the human/yeast TFIIH transcription factor subunit XPD/RAD3, regulates cold-stress genes in Arabidopsis thaliana. Plant Molecular Biology Reporter. 27:217-228. Interpretive Summary: Recent studies have shown that C-repeat/DRE-Binding Factor (CBF) family genes primarily regulate cold resistance or tolerance in plants, and mutations in or over-expression of CBF family genes could alter plant performance in cold conditions. In this study, we showed that the UVH6 gene, which confers resistance to UV light and heat stress in plants, also plays an important role in the regulation of cold resistance. Mutation of the UVH6 gene renders Arabidopsis plant sensitive to cold temperature and abolishes the expression of two cold-stress genes but does not affect expression of any CBF gene. Our studies indicate that plants have evolved multiple pathways or regulatory mechanisms to deal with cold stress and that UVH6 is a key master gene for controlling plant tolerance and resistance to a variety of environmental stresses. This information can be used by plant breeders to develop more adapted varieties.
Technical Abstract: The UVH6 gene from Arabidopsis thaliana is predicted to function in transcription regulation, based on known activities of its human and yeast homologs. In this study, we show that UVH6-1 mutants are ultra-sensitive to cold and suggest that this defect results from reduced expression of cold-stress genes. Comparison of mRNA levels in cold-treated wild-type and UVH6-1 plants reveals that expression of two cold-stress genes (Cor6.6 and Cor15a) is impaired in the mutant. In contrast, the mutant shows normal cold induction of three transcription factor genes (CBF1, 2, 3), which regulate these Cor genes, and normal induction of several additional CBF-targeted genes. Thus, we propose that UVH6 promotes cold resistance by specifically regulating transcription of Cor6.6 and Cor15a genes. We further find features among the regulatory sites in the Cor6.6 and Cor15a promoters which suggest unique regulation of these genes.