Expression Analysis Of Stress-Responsive Genes In Soybean Plants Overexpressing Gmnaco85 Under Normal And Salinity Conditions

Abstract

Salinity stress is among the major abiotic stresses that inhibit and impair plant growth and development. Therefore, understanding of salinity tolerance mechanisms in plants is very important in the field of biotechnology. Previous studies on different plant species have revealed the potential of manipulating transcription factor-encoding NAC (NAM, ATAF1/2, CUC2) genes for improving drought and salt tolerance. GmNAC085, a soybean (Glycine max) NAC gene, has been reported to increase its expression in soybean root and shoot tissues under dehydration and drought conditions, indicating its involvement in plant response to water deficit. In planta characterization of GmNAC085 in Arabidopsis also revealed its positive regulator role in enhancement of the plant tolerance to drought. As drought and salinity cause similar negative effects to plants, in this study, we were interested in investigating the biological function of GmNAC085 in plant response to salt stress by using transgenic soybean plants overexpressing GmNAC085 as studied materials. In the aspect of exploring the effect of transgene to transcriptional profile of several stress-related genes, including manganese superoxide dismutase (MnSOD), ascorbate peroxidase 1 (APX1), catalase (CAT), Na+/H+ antiporterencoding gene (NHX1) and proline metabolic gene (P5CS), it was found that the transgenic plants enhanced the expression of these genes under salt stress conditions. These obtained results provided supporting evidence for the positive contribution of GmNAC085 in mediating plant response to salinity, suggestively via enhancement of antioxidant enzymes, Na+/H+ antiporter-activity and biosynthesis of proline. Therefore, deeper investigation about GmNAC085 mechanism should be conducted in future work in order to evaluate its potential application in improving osmotic stress tolerance of crop plants.