Overexpression of <i>GmXTH1</i> Enhances Salt Stress Tolerance in Soybean

Abstract

Soybean is an important grain, oil and feed crop, which plays an important role in ensuring national food security. However, soil salinization hinders and destroys the normal physiological metabolism of soybean, resulting in the abnormal growth or death of soybean. The XTH gene can modify the plant cell wall and participate in the response and adaptation of plants to negative stress. To elucidate the role of the overexpressed GmXTH1 gene under NaCl-induced stress in soybean, we determined the germination rate, the germination potential, the germination index, seedling SOD activity, POD activity, the MDA content and the MDA content during the germination stage of the overexpressed lines of the GmXTH1 gene, the OEAs (OEA1, OEA2 and OEA3), the interference expression line IEA2, the control mutant M18, the CAT content and the chlorophyll content. The relative expression of the GmXTH1 gene in the material OEA1 and the contents of Na+ and K+ in the roots after stress were also determined. The results showed that OEAs exhibited enhanced germination indices, including the germination rate and germination potential, and were less sensitive to stress compared with the mutant M18. In contrast, the inhibitory effect of NaCl was more pronounced in the line with a disturbed expression of GmXTH1 (IEA2). The OEAs exhibited more enzyme activities and a lower MDA content, indicating reduced oxidative stress, and maintained higher chlorophyll levels, suggesting improved photosynthetic capacity. Relative expression analysis showed that the GmXTH1 gene was rapidly up-regulated in response to NaCl, peaking at 4 h after treatment, and subsequently declining. This temporal expression pattern correlated with the enhanced salt tolerance observed in OEA1. Notably, OEA1 accumulated more Na+ and maintained higher K+ levels, indicating effective ionic homeostasis under stress. Collectively, these results suggest that the overexpression of the GmXTH1 gene may positively regulate plant responses to salt stress by modulating the antioxidant defense and ion transport mechanisms.

Keywords

• soybean
• NaCl stress
• GmXTH1 gene overexpression
• GmXTH1 gene interference expression
• physiology and biochemistry
• ion uptake (Na⁺, K⁺)