A total of 42 protein kinase genes were found to be important for plant infection by systemic characterization of the F. graminearum kinome. One of them, FGSG_00472, is orthologous to SCH9 of the budding yeast. The Sch9 protein kinase shares sequence similarity with the catalytic subunits of PKA and it is functionally related to cAMP signaling in response to nutrient availability in Saccharomyces cerevisiae. It inhibits PKA activity by regulating the localization of Tpk1/2/3 and stability of Tpk2. Disruption of SCH9 increases PKA activities and stress tolerance. Similar to mutations in RAS2 and CYR1, down-regulation of glucose signaling by SB-649868 deletion of SCH9 increases longevity and resistance to oxidative stress and heat shock. In S. cerevisiae, SCH9 also is a master regulator of protein synthesis. It is phosphorylated by TORC1 to regulate TORC1-dependent cellular processes, such as ribosome production and translation. The Sch9 kinase also is involved in the regulation of autophagy together with the TORC1 and cAMPPKA pathways. Although SCH9 orthologs are well conserved in plant pathogenic fungi or filamentous ascomycetes, none of them have been functionally characterized. Considering the diverse functions of SCH9 in S. cerevisiae and the importance of cAMP signaling in F. graminearum, in this study we further characterized the Fgsch9 deletion mutant generated in the systemic characterization of the F. graminearum kinome. Although it was only slightly reduced in growth rate, the DFgsch9 mutant was significantly reduced in DON production and virulence. It had increased tolerance to elevated temperatures but increased sensitivities to oxidative, hyperosmotic, cell wall, and membrane stresses. The DFgsch9 deletion mutant also was defective in conidiogenesis and produced smaller conidia. In the rice blast fungus Magnaporthe oryzae, the DMosch9 deletion mutant also was defective in conidiogenesis and pathogenesis. Interestingly, it also produced smaller conidia and appressoria. These results indicate that the SCH9 kinase gene may have a conserved role in regulating conidium size and plant infection in plant pathogenic fungi. In the budding yeast, the Sch9 kinase is functionally related to the cAMP-signaling and TORC1 pathways. These two well-conserved QS11 pathways recently were shown to be involved in various development and infection processes in F. graminearum.