Funtional Analysis Of Acyltransferase Gene CMAT-1of Coniothyrium Minitans

Coniothyrium minitans, is an important sclerotial mycoparasite of Sclerotinia sclerotiorum, a plant pathogenic fungus. C. minitans could parasitize the hypha and sclerotia of S. sclerotiorum. Thus it has great potential for biological control of plant diseases caused by S. sclerotiorum. Commodity fungal agent has already been applied to practical production in Europe and the United States.When dual cultured with S. sclerotiorum, C. minitans produces antifungal substances (AFS) in acidic environment, which significantly inhibit the mycelial growth of S. sclerotiorum. In previous study, a mutant ZS-1T8512with the ability to produce AFS was uncovered from a T-DNA insertional library construted with the wild type strain ZS-1, and the gene inserted by the T-DNA insertion, CMAT-1, encoding acyltransferase was cloned. Here, in this research, the function of CMAT-1was identified through gene overexpression and RNAi. The results were as followed:Compared with wild type strain ZS-1, mutant ZS-1T8512has the following properties:The colony morphology was obviously different from ZS-1on potato dextrose agar, including density of colony, slower growth rate, conidiation defiency, and low parasitical ability on sclerotia of S. sclerotiorum, while the ability to produce antibacterial substances (ABS) and the bio-control ability were all enhanced. Particularly, the ability to produce antifungal substances was dramatically enhanced.Quantitative reverse transcription PCR (qRT-PCR) showed that CMAT-1was excessively expressed in mutant ZS-1T8512while was weak expressed in the wild type strain ZS-1. In order to identify the function of CMAT-1in C. minitans, the gene was over expressed in ZS-1by Agrobactirium tumfacience mediated-transformation, and two over expression transformants, OE3and OE9were obtained. They shared characteristics similar to mutant ZS-1T8512and, produced a large number of antifungal substances, a On the other hand, CMAT-1in ZS-1T8512was silenced and one silencing transformant named Si6was obtained. The expression of CMAT-1was significantly decreased compared to mutant ZS-1T8512, but still slightly higher than in the wild type strain ZS-1. Si6could not produce antifungal substances when dual cultured with S. sclerotiorum.The results show that CMAT-1play important roles in the growth, conidiation and AFS producing. The excessive expression of CMAT-1in C. minitans leads to the production of antifungal substances, which has obvious improvement effect for antibiotic ability of C. minitans. Study the mechanism of action and control of acyltransferase gene CMAT-1which is related to the production of antifungal substances in C. minitans, is conducive to us for better studying the production and the control process of producing antifungal substances in fungi, and provide basis for researching acyltransferase in C. minitans. At the same time, this makes it possible to apply the antibiotic effect of C. minitans in the actual biological control.