MOLECULAR DIVERSITY OF <em>COLLETOTRICHUM</em> ISOLATES FROM TROPICAL FOREST TREE SPECIES AND THEIR RELATIONSHIP WITH OTHER KNOWN <em>COLLETOTRICHUM</em> SPECIES

Abstract

The present study reveals species grouping in the genus Colletotrichum isolated from the tropical forest trees. The sequence data of domain 2 of the ribosomal DNA provided further evidence to distinguish isolates of Colletotrichum,
which could not be achieved by morphological and cultural criteria studies alone. Analysis of the 13 forest tree isolates suggests that they represent three main groups. Group 1 consists of only one isolate (689). Group 2 consists of isolates 634, 635,640, 645, 657, 659, 664 and 665. Of these isolates 645, 657, 659 and 665 were identical. Group 3 consists of isolates 630, 660, 662 and 674. The maximum percentage nucleotide difference between the groups was small, merely 5.2% (94.8 % similarity). Comparison of the forest isolates with other Colletotrichum species revealed that the forest isolates corresponded to some of the known species. Thus, some of the forest isolates had sequences that were identical to the defined species. In Group A, isolate 640 was identical to a C. gloeosporioides from Digitalis (120), whereas isolates 645, 657, 659 and 665 were identical to C. gloeosporioides from Aeschynomene (074) and Mangifera
(501). Isolate 689 was identical to C. acutatum from Musa (058) and Lupinus (163). In Group B, isolate 660 was identical to G. cingulata from Phaseolus (529 and 531) and Vigna (238). The morphological comparison of the isolates in each group is also presented.