Identification and expression analysis of HSP100 gene family in Aeluropus littoralis

Heat shock proteins (HSPs), molecular chaperones with many activities, are essential to plant growth, development, and stress responses. To make crops more salt- and drought-resistant, plant breeders have considered halophytic plant. Aeluropus littoralis, a halophyte monocot grass, is one potential model species to discover new stress-response genes. Here, exon/intron structure, conserved motifs/ domains, and expression patterns of HSP100 gene family were identified in the genome of A. littoralis. This study found six unique AlHSP100 non-repetitive genes, revealing remarkable structural and physicochemical variations between the subfamilies. Phylogenetic and motif analyses revealed that proteins from the same subfamily (AlHSP100.1-4) and proteins from other subfamilies (AlHSP100.5-6) have similar types, ordering, and quantities of motifs. Finally, the expression of AlHSP100.3 gene was analyzed using RT-qPCR under dehydration, salt, cold, and phytohormone abscisic acid stress treatments, revealed that their expression patterns vary in response to abiotic stresses. The presence of stress-dependent regulation of the HSP100.3 gene, as evidenced by the early response to osmotic stress and the late response to cold stress, is likely associated with the cis-regulatory elements located upstream of this gene. This study provides more valuable information to deepen our understanding of the abiotic stress responses by HSP100 genes in A. littoralis.