Genetic Diversity of a Global Population of Colletotrichum Coccodes Using Amplified Fragment Length Polymorphism Markers

The present study tested the hypothesis that the global C. coccodes population is genetically differentiated by region of origin. A total of 855 isolates, originating from North America (475), Europe (147), Israel (66), Australia (86), South Africa (14) and additional testers (67), which previously were assigned to VCGs (21 international VCGs) were examined for their genetic diversity. Using the previously assigned North American VCGs as the leading sub-population, and with the aid of amplified fragment length polymorphism (AFLP) markers, the isolates were grouped into five VCG/AFLP sub-populations (1, 2, 3, 4/5 and 6/7). These were distributed between two phylogeny clusters, designated Cc-A and Cc-B. Cluster Cc-A was unique and composed of isolates from VCG/AFLP6/7 only, whereas cluster Cc-B was composed of the remaining four VCG/AFLP sub-populations, which was further divided into 17 sub-clusters. VCG/AFLP4/5 was the most common VCG globally, followed by VCG/AFLP2. Most of the variation among the four geographic regions originated from the within population differentiation (84 %). It is concluded from these studies that the global population of C. coccodes exists as one large population with five main VCG/AFLPs worldwide and that they are probably of the same origin, however, geographic isolation caused these populations to differentiate and form distinct sub-clusters.