Molecular characterization, expression pattern and function analysis of the OsHSP90 family in rice

作者:Zhang, Hai; Li, Lihua; Ye, Taozhi; Chen, Rongjun; Gao, Xiaoling; Xu, Zhengjun*
来源:Biotechnology & Biotechnological Equipment, 2016, 30(4): 669-676.
DOI:10.1080/13102818.2016.1184588

摘要

The HSP90 is an abundant chaperone protein that is conserved in all eukaryotes. The main function of HSP90 is to assist other proteins to fold properly. In this study, we uncovered and analysed nine OsHSP90 (OsHSP90-1--OsHSP90-9) family members in rice Nipponbare, in which three distinct motifs were identified. All the HSP90 proteins were classified into three major groups (I, II, III) by phylogenetic analysis. The expression of OsHSP90 family in 10 tissues was examined by real-time polymerase chain reaction (PCR). OsHSP90-4, OsHSP90-6 and OsHSP90-7 had high expression, while OsHSP90-5 and OsHSP90-8 had very low expression across almost all 10 samples. The gene that encodes OsHSP90-1 was preferentially expressed in embryo at 14days after flowering. It has been reported that some heat shock proteins were up-regulated in response to heat or other stresses. However, in our study the expression pattern of OsHSP90 genes is heterogeneous under a range of stress conditions. The expression of OsHSP90-2 and OsHSP90-4 was up-regulated under drought, salt, cold and heat conditions, while the expression of OsHSP90-3 and OsHSP90-5 was down-regulated under salt and drought conditions. OsHSP90-7 and OsHSP90-9 were down-regulated only under drought conditions. OsHSP90-6 did not change its expression across all conditions compared to control. Overexpression of OsHSP90-2 in E. coli could enhance cell viability and significantly improved resistance to heat, high salinity and drought stress conditions. The results presented here may provide new insights into the function of OsHSP90 family in rice.