Uninterrupted Expression of CmSIT1 in a Sclerotial Parasite Coniothyrium minitans Leads to Reduced Growth and Enhanced Antifungal Ability

is an important mycoparasite of . In addition, it also produces small amounts of antifungal substances. ZS-1TN1812, an abnormal mutant, was originally screened from a T-DNA insertional library. This mutant showed abnormal growth phenotype and could significantly inhibit the growth of when dual-cultured on a PDA plate. When spraying the filtrate of ZS-1TN1812 on the leaves of rapeseed, infection was significantly inhibited, suggesting that the antifungal substances produced by this mutant were effective on rapeseed leaves. The thermo-tolerant antifungal substances could specifically suppress the growth of , but could not significantly suppress the growth of another fungus, . However, was more sensitive to proteinous antibiotics than . The T-DNA insertion in ZS-1TN1812 activated the expression of , a gene involved in siderophore-mediated iron transport. It was also determined that mutant ZS-1TN1812 produced hypha with high iron levels. In the wild-type strain ZS-1, was expressed only when in contact with , and consistent overexpression of showed similar phenotypes as ZS-1TN1812. Therefore, activated expression of leads to the enhanced antifungal ability, and is a potential gene for improving the control ability of .