AUTHOR=Sun Xiping , Zhao Ying , Jia Jichun , Xie Jiatao , Cheng Jiasen , Liu Huiquan , Jiang Daohong , Fu Yanping 

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

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.02208

DOI=10.3389/fmicb.2017.02208

ISSN=1664-302X

ABSTRACT=<p><italic>Coniothyrium minitans</italic> is an important mycoparasite of <italic>Sclerotinia sclerotiorum</italic>. 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 <italic>S. sclerotiorum</italic> when dual-cultured on a PDA plate. When spraying the filtrate of ZS-1TN1812 on the leaves of rapeseed, <italic>S. sclerotiorum</italic> 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 <italic>S. sclerotiorum</italic>, but could not significantly suppress the growth of another fungus, <italic>Colletotrichum higginsianum</italic>. However, <italic>C. higginsianum</italic> was more sensitive to proteinous antibiotics than <italic>S. sclerotiorum</italic>. The T-DNA insertion in ZS-1TN1812 activated the expression of <italic>CmSIT1</italic>, 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, <italic>CmSIT1</italic> was expressed only when in contact with <italic>S. sclerotiorum</italic>, and consistent overexpression of <italic>CmSIT1</italic> showed similar phenotypes as ZS-1TN1812. Therefore, activated expression of <italic>CmSIT1</italic> leads to the enhanced antifungal ability, and <italic>CmSIT1</italic> is a potential gene for improving the control ability of <italic>C. minitans</italic>.</p>