Molecular studies on intraspecific diversity and phylogenetic position of Coniothyrium minitans

Simple sequence repeat (SSR)-PCR amplification using a microsatellite prime r (GACA)(4) and ribosomal RNA gene sequencing were used to examine the intr aspecific diversity in the mycoparasite Coniothyrium minitans based on 48 s trains, representing eight colony types, from 17 countries world-wide, Coni othyrium cerealis, C. fuckelii and C. sporulosum were used for interspecifi c comparison. The SSR-FCR technique revealed a relatively low level of poly morphism within C. minitans but did allow some differentiation between stra ins. While there was no relationship between SSR-PCR profiles and colony ty pe, there was some limited correlation between these profiles and country o f origin. Sequences of the ITS I and ITS 2 regions and the 5.8S gene of rRN A genes were identical in all twenty-four strains of C. minitans examined i rrespective of colony type and origin. These results indicate that C. minit ans is genetically not very variable despite phenotypic differences. ITS an d 5.8S rRNA gene sequence analyses showed that C. minitans had similarities of 94 % with C. fuckelii and C. sporulosum (which were identical to each o ther) and only 64 % with C. cerealis. Database searches failed to show any similarity with the ITS 1 sequence for C. minitans although the 5.8S rRNA g ene and ITS 2 sequences revealed an 87% similarity with Aporospora terricol a. The ITS sequence including the 5.8S rRNA gene sequence of Coniothyrium c erealis showed 91% similarity to Phaeosphaeria microscopica. Phylogenetic a nalyses using database information suggest that C. minitans, C. sporulosum, C. fuckelii and A. terricola duster in one clade, grouping with Helminthos porium species and 'Leptosphaeria' bicolor. Coniothyrium cerealis grouped w ith Ampelomyces quisqualis and formed a major cluster with members of the P haeosphaeriacae and Phaeosphaeria microscopica.