The MAP Kinase Gene crmapk is Involved in Clonostachys chloroleuca Mycoparasitism.

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