PsGRGH, a TOS1 Family-Like Gene, is Involved in the Vegetative Growth, Environmental Stress Response, and Pathogenicity of Phytophthora Sojae

Phytophthora sojae can cause soybean phytophthora blight, and greatly reduce soybean production. It is helpful to understand the pathogenic mechanism of P. sojae to prevent soybean phytophthora blight and ensures food security. Glycosyl hydrolases (GHs) disintegrate plant cell walls for nutrition and invasion, and they may act as an important virulence factor during P. sojae infection. To reveal the role of GHs in the main stages of P. sojae life cycle, we measured the expression level of genes, which encoded GHs, and constructed P. sojae transformants for biological function verification by the gene editing technology CRISPR-Cas9. In this study, four genes, encoded special GH proteins, with conserved glycine-rich were identified in the P. sojae genome, and their sequences were similar to those of the TOS1 family genes. One of them, the xp_009520987.1, was named PsGRGH, and was significantly upregulated during the germination of spores and in the early infection stages. The results revealed that PsGRGH was involved in the growth and mycelial morphology regulation in P. sojae, and was essential for its sporangium development and virulence. In addition, PsGRGH is localized on the cell membrane and plays an important role in tolerance toward Bacillus and abiotic stress.