Isolation of GsNAC20 Gene from Glycine soja and Its Response to Abiotic Stresses

Plant-specific transcription factor family NAC (NAM, ATAF1/2, CUC2) plays essential roles in various biological processes including development, senescence, morphogenesis, and stress signal transduction pathway. An NAC gene, which was designated GsNAC20 and showed 99% similarity to GmNAC20 (EU440353.1) from Glycine max, was isolated from G. soja using yeast one hybrid method. The GsNAC20 protein possesses a typical NAC DNA-binding domain at the N-terminal and a transcription activation region at the C-terminal. Like GmNAC20, GsNAC20 could bind to MYB1AT element (the core sequence of AAACCA) in vitro, but no transcriptional activation activity was detected in the yeast assay system. Using the transient expression system in tobacco epidermis cells, GsNAC20 was confirmed to be localized in nucleus. The expression of GsNAC20 was induced by drought, low temperature and salt stress, and the expression patterns were different in leaf and root of G. soja. Overexpression of GsNAC20 gene in the transgenetic lines of Arabidopsis thaliana resulted in enhanced sensitivity of the transgenic plants under salt stress. All results prove that GsNAC20 is a new member of the NAC family in G. soja, which is closely related to the stresses of salt and drought.