Overexpression of a TIFY family gene, GsJAZ2, exhibits enhanced tolerance to alkaline stress in soybean

Previous studies have indicated the potential role of a TIFY family gene, GsJAZ2, for its response to alkaline stress in Arabidopsis. Here, we transformed GsJAZ2 into an elite soybean (Glycine max) using particle bombardment-based genetic transformation system to assess whether overexpression of GsJAZ2 in soybean improved alkaline tolerance. Results revealed that transgenic soybean overexpressing GsJAZ2 grew well under alkaline conditions, while wild-type (WT) plants exhibited chlorosis, stunted growth, or even death. Higher chlorophyll concentration and lower of Malondialdehyde (MDA) content were detected in the transgenic plants compared to WT under alkaline stress. Moreover, the transcription levels of two alkaline-responsive genes were up-regulated in the GsJAZ2 overexpression at the early or later stage of alkaline stress, respectively, indicating that GsJAZ2 overexpression enhanced tolerance to alkaline stress in soybean, which might modulate intracellular pH homeostasis and osmotic balance through regulating the expression of alkaline-responsive genes. Additionally, GsJAZ2 is a member of the JAZ subfamily that belongs to the TIFY family. Overexpression of GsJAZ2 in soybean conferred JA insensitivity, including JA-mediated root growth inhibition. The transcripts of some JA-responsive genes were examined and altered under alkaline stress, implying that GsJAZ2 overexpression may involve in JA signal pathway for accumulating anti-osmotic substances in defense to alkaline stress. Collectively, the findings of this study facilitate our understanding of GsJAZ2 in response to alkaline stress as well as enrich the function of TIFY genes in crop.