The Mitogen-Activated Protein Kinase Gene Crmapk Is Involved in Clonostachys chloroleuca Mycoparasitism

is a mycoparasite used for biocontrol of numerous fungal plant pathogens. Sequencing of the transcriptome of following mycoparasitization of the sclerotia of revealed significant upregulation of a mitogen-activated protein kinase (MAPK)-encoding gene, . Although MAPKs are known to regulate fungal growth and development, the function of in mycoparasitism is unclear. In this study, we investigated the role of in mycoparasitism through gene knockout and complementation. Deletion of had no influence on the morphological characteristics but could significantly reduce the mycoparasitic ability to sclerotia and biocontrol capacity to soybean Sclerotinia stem rot; complementation restored these abilities. Transcriptome analysis between Δ and the wild-type strain revealed numerous genes were significantly down-regulated after deletion, including cytochrome P450, transporters, and cell wall-degrading enzymes (CWDEs). Our findings indicate that influences mycoparasitism by regulation of genes controlling the activity of CWDEs or antibiotic production. This study provides a basis for further studies of the molecular mechanism of mycoparasitism.