Abstract
It was reported that sfr2 (sensitive to freezing 2) gene plays an important role in freezing sensitivity in Arabidopsis (Thorlby et al., 2004). Arabidopsis sfr2 protein can be classified into family 1 glycosyl hydrolase based on deduced amino acid sequence and shows a specific β-glucosidase activity. However, expression of Arabidopsis sfr2 gene was observed to be constitutive rather than cold stress inducible. We detected a rice cDNA (OsSFR2) in the public databases, which encodes homolog of Arabidopsis sfr2 gene. Rice OsSFR2 protein has 60% homology at amino acid level to Arabidopsis SFR2 protein. Southern analysis with OsSFR2 full-length probe revealed that more than two closely related genes might exist in rice genome. Northern analysis with OsSFR2 gene specific probe showed that the gene is expressed strongly in rice seedling leaves in response to cold stress. These results indicate that OsSFR2 may be involved in cold stress response in rice seedlings.
