Abstract:

Heat shock protein 20 (HSP20) plays a critical role in plant growth, development, and response to abiotic stress. Although HSP20 genes have been associated with heat stress in numerous types of plants, there is little research on HSP20 (RcHSP20) gene family in Rosa chinensis. In order to investigate the response mechanism of RcHSP20 to heat stress, all members of HSP20 gene family in R. chinensis were identified and analyzed based on whole genome identification. A total of 31 RcHSP20 genes were identified and their physicochemical properties were analyzed. System evolution analysis shows that RcHSP20 can be divided into 4 subtypes. The duplicated event analysis demonstrated that tandem duplication and segment duplication events played crucial roles in promoting the expansion of RcHSP20 gene family. Collinearity analysis showed that R. chinensis shared the highest homology in 21 HSP20 gene pairs with Rosa rugosa, followed by 5 and 2 homologous gene pairs with Arabidopsis thaliana and Oryza sativa, respectively. The expression pattern of RcHSP20-7, RcHSP20-8, RcHSP20-1, RcHSP20-14, RcHSP20-2, RcHSP20-3 and RcHSP20-5 in the CⅠ subfamily showed a high degree of similarity. After being subjected to 0.5 hours of heat stress, the expression level began to increase. When the heat stress time was prolonged to 2 hours, the gene expression level increased until reaching its peak. However, the expression levels of these genes gradually decreased after 6-12 hours of heat stress. The results indicate that these RcHSP20 genes may play a crucial role in participating in heat stress response.

Key words: Rosa chinensis, HSP20, bioinformatics, gene family