Stress responsive glycosylphosphatidylinositol-anchored protein SsGSP1 contributes to virulence.

Fungal cell wall acts as a defense barrier, shielding the cell from varying environmental stresses. Cell wall proteins, such as glycosylphosphatidylinositol (GPI)-anchored proteins, are involved in swift and appropriate responses to minor environmental changes in fungi. However, the roles of these proteins in the pathogenic remain largely unexplored. Here, we identified a novel GPI-anchored protein in , SsGSP1, comprising a Kre9_KNH domain. was upregulated during infection, and the loss-of-function mutants of exhibited the compromised cell wall integrity and reduced β-glucan content. During inoculation on , , and , the -deletion strains demonstrated the decreased virulence. The transgenic . line carrying the sRNA targeting enhanced resistance to via Host-Induced Gene Silencing (HIGS). The -deficient strains displayed the heightened sensitivity to various stresses, including osmotic pressure, oxidative stress, and heat shock. The yeast two-hybrid and BiFC assays confirmed that SsGSP1 interacted with the key stress-related proteins catalase SsCat2, heat shock protein Sshsp60, and ABC transporter SsBMR1. Accordingly, transcriptome analysis revealed that the disruption of downregulated the expression of genes involved in oxidative stress response, heat shock response, and chemical agent resistance. These results collectively delineate the intricate role of GPI-anchored protein SsGSP1 in β-glucan, cell wall integrity, and virulence and may act as a potential surface sensor to elicit signal transduction in response to environmental stresses in .