Genetic diversity of Colletotrichum fructicola isolates using ISSR molecular marker and efficiency of this technique in differentiating this species from several Colletotrichum species

In this study, genetic diversity of 70 isolates of Colletotrichum fructicola obtained from the leaf spot symptoms on a variety of cultivated and wild plants in different regions of three northern provinces of Iran, including Guilan, Mazandaran and Golestan, was investigated using the ISSR molecular marker. Cluster analysis of the results of DNA fingerprinting using five ISSR primers for 70 isolates of C. fructicola cleraly reverlaed genetic diversity among the isolates. Based on this, 70 isolates were differentiated into eight colonal lineages. These results showed that there is a high level of genetic diversity among isolates of this fungal species. No direct correlation between DNA fingerprinting groups and geographical origin and host of the isolates was observed. In order to evaluate the efficiency of ISSR molecular marker in differentiating C. fructicola isolates from isolates of some close and dominant species of the genus Colletotrichum, DNA fingerprinting using this molecular marker for 89 isolates including 85 C. fructicola isolates, two C. gloeosporioides isolates, one isolate for each of C. aenigma and C. karstii was performed. Based on the comparison of the DNA fingerprinting pattern and the drawn phenogram, 89 isolates were placed in four main groups (A-D) at the genetic similarity level of 70%. So that the isolates of colonal lineages A-D belonged to C. karstii, C. fructicola, C. gloeosporioides and C. aenigma species, respectively. To ensure the accuracy of the identification, 28 isolates from different clonal lineages were selected as representatives for molecular identification based on the sequencing of the beta-tubulin (TUB2) gene region and the APN2/MAT1 (ApMAT) intergenic space. Phylogenetic analysis showed the accuracy of identification and the efficiency of ISSR molecular marker as a useful tool in grouping and separating the dominant species of the genus Colletotrichum.