GmNAC3基因过表达提升大豆耐盐碱性OA

To further explore salt-alkali tolerance genes in soybean and create salt-alkali tolerant transgenic soybean materials,this study focused on the candidate salt-alkali tolerance gene GmNAC3,identified through previous RNA-Seq data analysis.Using real-time quantitative PCR(RT-qPCR),to study whether this gene was induced by salt-alkali stress.Overexpressing transgenic lines were generated via the cotyledonary node transformation method,and the role of GmNAC3 in response to salt-alkali stress was elucidated through phenotypic analysis and biomass measurement.RT-qPCR analysis,combined with measurements of antioxidant enzyme activities and malondialdehyde(MDA)content,further revealed the function of GmNAC3 in enhancing antioxidant capacity in soybean,uncovering its important role in improving salt-alkali tolerance.The results showed that GmNAC3 is expressed in various soybean tissues,including leaves,flowers,and seeds.Among these,the expression level of GmNAC3 was highest in leaves,with relative expression approximately 12.7 times that in roots and 20 times that in stems,and significantly higher than in cotyledons,flowers,seeds,and pod-bearing seeds,indicating tissue-specific expression in leaves.RT-qPCR analysis under salt-alkali stress conditions revealed that salt-alkali treatment significantly induced GmNAC3 expression.As treatment time increased,GmNAC3 expression levels gradually rose,peaking at 12 hours after treatment,with a relative expression level 6.36 times that of the control.Phenotypic analysis of GmNAC3 overexpressing lines under salt-alkali stress demonstrated that overexpression of GmNAC3 significantly enhanced soybean salt-alkali tolerance,with biomass significantly increased compared to the receptor material.Antioxidant enzyme activity analysis showed that in GmNAC3 overexpressing lines L1 and L2,superoxide dismutase(SOD)activity increased by 109%and 88%,peroxidase(POD)activity increased by 105%and 76%,and catalase(CAT)activity increased by 96%and 91%,respectively,compared to the receptor material.Meanwhile,malondialdehyde(MDA)content significantly decreased by 47%and 36%.These results indicate that overexpression of GmNAC3 significantly enhanced the antioxidant capacity of the transgenic lines.In summary,this study elucidates the mechanism by which the GmNAC3 gene improves salt-alkali tolerance in soybean.The overexpressing lines generated in this study provide new potential materials for salt-alkali tolerance breeding in soybean and soybean production in saline-alkali soils.