Overexpression of a phospholipase Dα gene from Ammopiptanthus nanus enhances salt tolerance of phospholipase Dα1-deficient Arabidopsis mutant

A phospholipase D alpha gene ( AnPLD alpha ) was cloned from xerophytic desert plant Ammopiptanthus nanus and its overexpression enhanced salt tolerance of a PLD alpha 1 deficient Arabidopsis mutant. Phospholipase D alpha (PLD alpha) hydrolyzes phosphatidylcholine to produce phosphatidic acid, and plays crucial role in plant tolerance to abiotic stress. In this study, a phospholipase D alpha gene (AnPLD alpha) was cloned from xerophyte Ammopiptanthus nanus by the methods of homologous cloning and rapid amplification of cDNA ends, and evaluated for its function in stress tolerance. The full-length cDNA was 2832 bp long, containing an open reading frame of 2427 bp that encodes 808 amino acids. The putative protein was predicted to be localized to the cytoplasm and this was confirmed by transient expression of a fluorescent fusion protein. The endogenous expression of the AnPLD alpha gene was induced by high salt, dehydration, cold and abscisic acid. The heterologous expression of the AnPLD alpha gene improved salt tolerance of an Arabidopsis pld alpha 1 knocked out mutant, and positively regulated the expression of the AtABI, AtNCED, AtRD29A, AtRD29B and AtADH genes. Therefore, the AnPLD alpha gene was concluded to be involved in response to abiotic stress. The AnPLD alpha gene is a hopeful candidate for transgenic application to improve stress tolerance of commercial crops.