The heat shock protein 90 (Hsp90) is a protein produced in plants in response to stress. This study identified and analyzed Hsp90 gene family members in the perennial ryegrass genome. From the results, eight Hsp90 proteins were obtained and their MW, pI and number of amino acid bases varied. The amino acid bases ranged from 526 to 862. The CDS also ranged from 20 (LpHsp0-4) to 1 (LpHsp90-5). The least number of CDS regions was 1 (LpHsp90-5) with 528 kb amino acids, while the highest was 20 (LpHsp90-4) with 862 kb amino acids, which showed diversity among the protein sequences. The phylogenetic tree revealed that Hsp90 genes in Lolium perenne, Arabidopsis thaliana, Oryza sativa and Brachypodium distachyon could be divided into two groups with five paralogous gene pairs and three orthologous gene pairs. The expression analysis after perennial ryegrass was subjected to heat, salt, chromium (Cr), cadmium (Cd), polyethylene glycol (PEG) and abscisic acid (ABA) revealed that LpHsp90 genes were generally highly expressed under heat stress, but only two LpHsp90 proteins were expressed under Cr stresses. Additionally, the expression of the LpHsp90 proteins differed at each time point in all treatments. This study provides the basis for an understanding of the functions of LpHsp90 proteins in abiotic stress studies and in plant breeding.
Keywords: Hsp90; abiotic stress; expression profiles; perennial ryegrass; phylogenetic analysis.