Small heat shock protein (Hsp20) gene family in Phaseolus vulgaris L.: Genome-wide identification, evolutionary and expression analysis

Understanding the mechanisms responsible for plant tolerance under various abiotic stresses is linked to understanding heat shock proteins (Hsps). The Hsp20 subfamily is the main family of heat shock proteins, but little is known about this family in common bean (Phaseolus vulgaris L.), an important agricultural crop sensitive to temperature and salt stress. We identified 41 candidate common bean Hsp20 genes (PvHsp20). We mapped the PvHsp20 genes according to their chromosomal locations and found 49 duplications, 35 segmental and 14 tandem. Subsequent gene structure analysis identified regions of exons, introns, and conserved motifs. In the phylogenetic analysis, all PvHsp20 genes were grouped into 11 subfamilies, except for two genes that could not be classified. Synteny analysis revealed that Hsp20 genes from the common bean are highly related to soybean. Promoter analysis of PvHsp20 genes showed the presence of hormone-related, light-responsive and stress-responsive cis-regulatory elements. 8 PvHsp20 genes were under the regulation of 8 PvmiRNA genes. The in silico expression profile showed that PvHsp20 was differentially expressed. The gene expression of the PvHsp20-31, PvHsp20-27, PvHsp-2, and PvHsp20-39 genes in the roots of the Ispir genotype suggested that these genes might play a vital role in the salt tolerance mechanism. Our results provide new information, contribute to understanding PvHsp20 genes, and validate their role in mitigating the adverse effects triggered by abiotic stresses.