Genome-wide identification and expression profile analysis of the Hsp20 gene family in Barley (Hordeum vulgare L.)

In plants, heat shock proteins (Hsps) play important roles in response to diverse stresses. Hsp20 is the major family of Hsps, but their role remains poorly understood in barley (Hordeum vulgare L.). To reveal the mechanisms of barley Hsp20s (HvHsp20s) response to stress conditions, we performed a comprehensive genome-wide analysis of the HvHsp20 gene family using bioinformatics-based methods. In total, 38 putative HvHsp20s were identified in barley and grouped into four subfamilies (C, CP, PX, and MT) based on predicted subcellular localization and their phylogenetic relationships. A sequence analysis indicated that most HvHsp20 genes have no intron or one with a relatively short length. In addition, the same group of HvHsp20 proteins in the phylogenetic tree shared similar gene structure and motifs, indicating that they were highly conserved and might have similar function. Based on RNA-seq data analysis, we showed that the transcript levels of HvHsp20 genes could be induced largely by abiotic and biotic stresses such as heat, salt, and powdery mildew. Three HvHsp20 genes, HORVU7Hr1G036540, HORVU7Hr1G036470, and HORVU3Hr1G007500, were up-regulated under biotic and abiotic stresses, suggesting their potential roles in mediating the response of barley plants to environment stresses. These results provide valuable information for further understanding the complex mechanisms of HvHsp20 gene family in barley.