Preliminary Studies On Interaction Between Coniothyrium Minitan And Sclerotinia Sclerotiorum/Botrytis Cinerea

Coniothyrium minitans is a sclerotial mycoparasite of the plant-pathogenic fungus Sclerotinia sclerotiorum, while it is unable to parasitize Botrytis cinerea, a closely related fungus of S.scelrotiorum. In this paper, we used the interaction models of C. minitans-S. sclerotiorum or -B. cinerea to study the biological characteristics and mRNA expression profiles during the early interaction of these fungi. A gene CMA11172 of C. minitans was screened from this study and a preliminary function identification of this gene was conducted. The results are as follows:Biological experiments shown that C. minitans could successful parasitize both mycelia and sclerotia of S. sclerotiorum, to absorb nutrients and produce conidia, but failed to parasitize either hyphae or sclerotia of B. cinerea. Both mycelia and sclerotia of S. sclerotiorum could stimulate conidia germination of C. minitans, while B.cinerea could not. C. minitans, however, could grow on inactivated sclerotia of B. cinerea and produce more conidia than those produced on sclerotia of S. sclerotiorum under the same conditions.By using the Solexa sequencing technology, we obtained the gene expression profiles during the early interaction of C. minitans-S. sclerotiorum or -B. cinerea. For each fungus, the number of differentially expressed genes was more than 1000. The results of mRNA expression profiles was verified by RT-PCR. Some genes was screened from this study. A gene CMA11172 of C. minitans whose expression was increased when induced by S. sclerotiorum but not by B. cinerea. Homologous genes SS1G₁0985 and BC1G₁1347 whose expression was increased when induced by C. minitans, but SS1G₁0985 have a enhanced increasing. SS1G₀3247 and BC1G₀6796 whose expression decreased when induced by C. minitans, but SS1G₀3247 decreased at the beginning of the interaction with Coniothyrium, however BC1G 06796 decreased 12h after the interaction.We constructed an overexpression vector, namely pC11172OE for CMA11172 gene to transform C. minitans strain ZS-1 by using Agrobacterium tumefaciens-mediated transformation （ATMT） techniques. We obtained 38 transformants. Among these,5 overexpressed transformants were obtained by detection of the hygromycin resistance gene and the expression levels of CMA11172 using PCR and RT-PCR. All of the overexpressed transformants shown more branches near the hyphae tip and the ability of anti-bacterium activity was increased compared to ZS-1. However, they can’t parasitize B.cinerea and the parasitization ability to S. sclerotiorum was not increased. In addition, the growth rate of partial transformants was decreased significantly and the yellow area between these with B. cinerea appear later than ZS-1.