The small heat shock proteins, chaperonin 10, in plants: An evolutionary view and emerging functional diversity

Small heat shock proteins (sHSPs) constitute a class of molecular chaperones, which are evolutionarily conserved yet diverse group of molecules, rapidly produced in response to stress. In this study, we sought to identify plant sHSPs, especially chaperonin 10 (Cpn10) family members in major evolutionary lineages, and determine their biological significance. Multiple sequence alignment of Cpn10 domains revealed divergent amino acids as well as conserved sites. Phylogenetic tree depicted the diversification and expansion of Cpn10 gene family. During the process of evolution, the Ka/Ks ratio of orthologous and paralogous pairs was <1, suggesting their evolutionary convergence and biological relevance. Functional annotations demonstrated that Cpn10 are involved in protein folding, regulation of metabolic processes and abiotic stress responses. Furthermore, subcellular localization prediction revealed that Cpn10 proteins are localized in multiple compartments, indicating a critical cellcoordinated defense. In-silico gene expression analysis exhibited their expression in most tissues examined, implying functional redundancy. Interactome analysis illustrated their interaction with chloroplast and mitochondrial genes, which are majorly involved in protein folding and assembly. The transcriptional regulation revealed their stress-responsive and distinct physiological roles. Our findings would contribute to new insights on the evolutionary history of Cpn10 gene family and the distinct biological roles.