Isolation and characterization of phospholipase D in response to abiotic stress from Vigna radiata (L.) Wilczek

Abiotic stress adversely impacts upon plant growth, survival and crop production. The Phosphoinositide pathway (PI) in plants is involved in various developmental pathways and defense mechanisms, in order to survive a plethora of environmental stresses. Phospholipase D is an essential phospholipid, which plays crucial roles in PI pathway. In this study, we report the isolation and characterization of PLD in response to various abiotic stress factors in Vigna radiata. The full-length cDNA sequence of VrPLD was isolated using the RACE-PCR approach and identified to be comprised of an open reading frame of 2430 bp encoding a protein of 809 amino acids. The deduced amino acid sequence revealed significant similarity with PLDs from other plant species. Phylogenetic analysis indicated that VrPLD belongs to the PLD group and contains two characteristic active site motifs, a single C2 and a C-terminal domain. The deduced aminoacid sequence of VrPLD exhibited a theoretical isoelectric point of 5.57 and a calculated molecular weight of 91.5 kDa. The secondary and tertiary structure of VrPLD was predicted to be primarily composed of random coils. In addition, the gene expression analyses showed that VrPLD was down-regulated by wounds and up-regulated by drought, salicylic acid, cold, salinity and high-temperature stress. This is the first report to demonstrate the role of VrPLD in response to abiotic stress. Our results suggest that there is an intricate association between PLD expression and abiotic stress. These findings could potentially warrant subsequent studies to elucidate core functional regulations in Vigna radiata in the future.