Molecular characterization and expression analysis of pearl millet plasma membrane proteolipid 3 (Pmp3) genes in response to abiotic stress conditions

Plasma membrane proteolipid 3 (Pmp3) is a gene family involved in abiotic stress response and cellular protection. Here we report cloning of two genes PgPmp3-1 and PgPmp3-2 from Pennisetum glaucum, and characterization with respect to their functions and responsiveness to various abiotic stresses. Both PgPmp3-1 and PgPmp3-2 genes are 171bp long and encode for 56 amino acid long peptides. PgPmp3 sequences share 70–99% sequence identity with their homologs. Protein secondary structure prediction revealed membrane-spanning regions containing a membrane potential modulator domain in both PgPmp3 proteins. In silico network analyses revealed Pmp3 co-expression and association with proteins conferring abiotic stress tolerance in plants. Expression profiles of PgPmp3-1 and PgPmp3-2 revealed their up-regulation in P. glaucum under cold and salt stresses, but showed reduced expression in response to heat stress. These findings provide insight into the role of P. glaucum Pmp3 in abiotic stress amelioration.