Diversity and molecular relationships of endophytic Colletotrichum isolates from the Iwokrama Forest Reserve, Guyana.

The diversity and host specificity were studied of a collection of Colletotrichum strains derived from endophytic colonies in leaves of 12 tree species in the Iwokrama Forest Reserve, Guyana. Analysis included ISSR-PCR and RAPD molecular fingerprinting techniques, rDNA ITS sequencing and morphological and cultural characterization. Most strains belonged to one of two species, C. gloeosporioides and a further taxon which is probably referable to C. boninense. Almost no strains were found to be genetically identical, indicating that clonal reproduction does not play a prominent role. No degree of host specificity could be detected even at molecular fingerprint level. The implications for estimation of fungal diversity in closed tropical forests may be profound.