The soybean transcription factor GmNAC085 enhances drought tolerance in Arabidopsis

The plant-specific NAC (NAM, ATAF1/2, and CUC2) transcription factors have been known to be involved in regulation of plant response and tolerance to drought. In this study, we analyzed the functions of the dehydration-inducible GmNAC085 isolated from soybean in regulation of plant adaptation to drought using the heterologous Arabidopsis system. GmNAC085 was shown to act as a transcriptional activator in a yeast assay, with the activation domain located in its C-terminus. In comparison with wild-type, transgenic Arabidopsis plants (35S:GmNAC085) constitutively overexpressing GmNAC085 exhibited slightly retarded growth, but improved tolerance to drought which was positively correlated with enhanced cell membrane integrity and reduced transpiration rate under water deficit. Furthermore, reduced malondialdehyde (a product of lipid peroxidation) content accompanied by increased activities of superoxide dismutase, catalase and ascorbate peroxidase in 35S:GmNAC085 plants indicated that the overexpression of GmNAC085 enhanced antioxidant capacity in the transgenic plants to reduce drought-induced oxidative damage. Consistently, a greater expression of the antioxidant enzyme-encoding and other well-known NAC-mediated drought-responsive genes was observed in 35S:GmNAC085 than in wild-type plants under drought. These results provide an insight into the positive role of GmNAC085 in regulating plant adaptation to drought, thereby suggesting potential applications of GmNAC085 for developing drought-tolerant transgenic crops.