Résumé
Heat shock proteins (Hsps) are a class of molecular chaperons which are crucial for protein folding, assembly, and translocation in many normal cellular processes. They stabilize proteins and membranes, and can assist in protein refolding under stress conditions in plants. Pearl millet (Pennisetum glaucum) is highly abiotic stress tolerant, but its Hsps have not been characterized. In the present study, PgHsp70 genes were retrieved and gene information analyzed in order to characterize their structure, localization and functions. Genome-wide screening using the tools of bioinformatics identified 18 PgHsp70 genes in the pearl millet genome which have been categorized into four subfamilies depending on their cellular localization such as endoplasmic reticulum, mitochondria, chloroplast and cytoplasm. Number of introns ranged from 0–11 in PgHsp70 family genes and the genes are located across 1 to 7 chromosomes. Phylogenetic analysis of Hsp70s revealed that they are closely related to Sorghum Hsp70s. Promoter analysis showed the presence of cisacting elements such as GCN4, HSE, LTR, MBS, ABRE, MYB, and TC Aassociated with abiotic stress conditions indicating the involvement of these genes in the abiotic stress. Under vapour pressure deficit (VPD) conditions, leaf and root tissues of VPD-sensitive ICMR 1152 line, showed mild expression and in the presence of high VPD, VPD-insensitive ICMR1122 PgHsp70 genes showed high expression in leaf and root tissues in comparison with VPD-sensitive line. Gene PgcHsp70-1 displayed high transcript level under high VPD conditions. These results expand our horizon of understanding of the structure and function of Hsp70s, especially under abiotic stress conditions which can further be validated and employed in breeding programs and genetic engineering.