Expression and Cloning of OrCrGHl, a Novel Cold-responsive Gene in Chaling Common Wild Rice
Hunan Provincial Key Laboratory of Crop Sterile Germplasm Resources Innovation and Application, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
Abstract： In order to identify novel cold-tolerance genes in rice, genome-wide gene expression profiling of Chaling common wild rice (CWR) and the cultivar indica rice Peiai 64S subjected to cold stress was perfor-med at the seedling stage using the GeneChip Rice Genome Array. A gene, designated OrCrGHl (Oryza rufi-pogon cold responsive glucan hydrolase-like), was screened from Chaling CWR as a cold-tolerance candi-date, which was highly responsive to cold stress in Chaling CWR but not in Peiai 64S. The expression pro-file of OrCrGHl obtained by the microarray analysis was confirmed by real-time quantitative PCR, suggesting that OrCrGHl is a cold-responsive gene in Chaling CWR. Its full open reading frame (ORF)-containing cD-NA clone was obtained by reverse transcription PCR (RT-PCR). Its sequence analysis showed that it encodes a glucan hydrolase-like protein of 558 amino acid residues, with a molecular weight of 59.252 kD and pI value of 5.81. The deduced amino acid sequence was completely identical with that of the glucan endo-1,3-beta-glucosidase GII isoform X2 of japonica rice Nipponbare, and was 99.28% identical with that of hypo-thetical protein OsI_26347 of indica rice 93-11. Analysis of the putative promoter region revealed several cis-acing regulatory elements that may be related to stress or stress hormone responses. The results indicated that OrCrGHl is a novel candidate gene associated with cold tolerance in wild rice. Further study is in progress to understand more about the gene.
