Involvement of the Mitochondrial Protein Tyrosine Phosphatase PTPM1 in the Promotion of Conidiation, Development, and Pathogenicity in .

The phosphorylation status of proteins, which is determined by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), governs many cellular actions. In fungal pathogens, phosphorylation-mediated signal transduction has been considered to be one of the most important mechanisms in pathogenicity. is an economically important corn pathogen. However, whether phosphorylation is involved in its pathogenicity is unknown. A mitochondrial protein tyrosine phosphatase gene, designated , was deduced in through the use of bioinformatics and confirmed by enzyme activity assays and observation of its subcellular localization. We then created a deletion mutant (Δ) to analyze its biological function. The results indicated that the loss of dramatically affected the formation of conidia and the development and differentiation into appressoria. However, the colony growth and conidial morphology of the Δ strains were unaffected. Importantly, the Δ mutant strains exhibited an obvious reduction of virulence, and the delayed infected hyphae failed to expand in the host cells. In comparison with the wild-type, Δ accumulated a larger amount of HO and was sensitive to exogenous HO. Interestingly, the host cells infected by the mutant also exhibited an increased accumulation of HO around the infection sites. Since the expression of the , , , and genes was upregulated with the HO treatment, our results suggest that the mitochondrial protein tyrosine phosphatase PTPM1 plays an essential role in promoting the pathogenicity of by regulating the excessive and production of HO.