A secreted glycerophosphodiester phosphodiesterase (GDPD) domain–containing protein, FpGDPD, is involved in <i>Fusarium pseudograminearum</i> virulence

Microbial pathogens secrete a diverse array of proteins to manipulate plant defense mechanisms and facilitate infection. However, few secreted proteins were thoroughly characterized in <i>Fusarium pseudograminearum</i>. Here, we identify and characterize <i>FpGDPD</i>, a gene encoding a secretory glycerophosphodiester phosphodiesterase (GDPD) domain–containing protein in <i>F. pseudograminearum</i>. We found that <i>FpGDPD</i> expression was significantly upregulated during specific stages of fungal infection. Disruption of <i>FpGDPD</i> in <i>F. pseudograminearum</i> did not affect vegetative growth, stress responses, or conidiation but enhanced phosphate tolerance and reduced fungal virulence in wheat. Furthermore, we demonstrated the secretory nature of the N-terminal signal peptide of FpGDPD and that the signal peptide contributes to <i>F. pseudograminearum</i> pathogenicity. Interestingly, FpGDPD triggers immune responses in <i>Nicotiana benthamiana</i>, inducing reactive oxygen species (ROS) accumulation and upregulating defense-related genes. Collectively, our findings reveal that FpGDPD plays a dual role: it promotes fungal virulence while simultaneously eliciting plant immune responses.