Analysis Of Antioxidant Enzyme Activities In Gmnac085 Overexpressing Soybean Plant Exposed To Salinity Stress Condition

Abstract

Osmotic stresses including drought and soil salinity are the environmental stressors that negatively affects plant growth and development. One of the reasons is due to the accumulation of reactive oxygen species (ROS) in plants under these adverse conditions, which leads to oxidative damages of plant cell structure and activities. In response, plants have to use enzymatic and nonenzymatic strategies to scavenge the excessive ROS. Scientific studies have highlighted the plant defense-mediated roles of NAC transcription factors (NAM, ATAF1/2, and CUC2) in coping with osmotic stress factors. Recently, soybean GmNAC085 has been found to be one of the most highly induced genes by dehydration and drought. In addition, the in plant a characterization of GmNAC085 using Arabidopsis system has demonstrated its positive functions in enhancement of the drought tolerance of transgenic plants, at least by facilitating the activities of antioxidant enzymes. Therefore, in this study, antioxidant enzymatic activities of transgenic plants harboring GmNAC085 was analyzed under salt stress, to find out if GmNAC085 also play a role on this. The obtained results revealed that in comparison with the wild-type plants, the transgenic plants had lower levels of hydrogen peroxide, in couple with higher activity levels of catalase and peroxidase, the enzymes that are responsible for hydrogen peroxide detoxification. In addition, pronounced activities of superoxide dismutase enzymes which are in charge of scavenging another type of ROS, superoxide radicals, were also observed in the salt-treated transgenic plants. These findings indicate GmNAC085 has regulatory function in enhancing antioxidant defense in plants against oxidative damage under salinity stress conditions.