FgPel2, a Secreted Pectate Lyase, Acts as a Virulence Factor in Fusarium graminearum.

Pectate lyases (Pels) are critical cell wall-degrading enzymes that facilitate plant infection by many phytopathogens. However, their functional contributions in Fusarium graminearum remain largely unexplored. Here, we identified and functionally characterized FgPel2, a pectate lyase in F. graminearum. FgPel2 possesses a functional signal peptide that confers secretion capability, and its transcript levels was significantly upregulated during wheat spike infection. Subcellular localization analyses revealed that FgPel2 associated with the cell wall. Overexpression of FgPel2 (OE‑FgPel2) significantly enhanced fungal virulence on wheat seedling leaves , suggesting a virulence-associated function. A silencing strain (FgPel2‑S) generated by RNA interference exhibited normal vegetative growth, conidiation, and sexual reproduction but displayed markedly increased sensitivity to cell wall stress, particularly to Calcofluor White (CFW). Importantly, the FgPel2‑S strain did not show reduced pathogenicity compared with the wild type, whereas OE‑FgPel2 led to enhanced pathogen virulence. These findings demonstrate that FgPel2 acts as a virulence factor in F. graminearum and imply functional redundancy with other pectate lyase family members.