GmLac55 Enhanced Soybean Resistance Against Soybean Cyst Nematodes Through Lignin Biosynthesis.

Soybean cyst nematodes (SCNs) are a significant disease that causes yield loss and reducing seed quality in soybeans (Glycine max). Developing SCN-resistant soybean varieties can minimize the need for insecticide use and reduce yield loss. Cinnamate-4-hydroxylase (C4H) and laccase (Lac) are key enzymes in the lignin synthesis pathway. In this study, SCN stress significantly promoted lignin accumulation in soybean roots and upregulated the expression of lignin signaling pathway genes GmC4H (Glyma.02G236500), GmLac55 (Glyma.13G076900), and GmLac85 (Glyma.20G051900). Using Agrobacterium rhizogenes-mediated transformation, the pNI900 expression vector was introduced into the soybean cultivar Williams 82 to generate GmLac55-overexpressing plants. The overexpression of GmLac55 enhanced soybean roots resistance to SCN and inhibited the further development of J2 larvae. Our study presents a strategy for increasing SCN resistance in soybean through Agrobacterium-mediated targeted mutagenesis of the GmLac55 gene.