Colletotrichum gloeosporioides is not a common pathogen on tropical fruits

Colletotrichum gloeosporioides has been reported as one of the most important pathogens worldwide that infect at least 1000 plant species. Fruit rots (anthracnose) are often attributed to C. gloeosporioides and, to a lesser extent, to C. acutatum. These previous findings were, however, based on morphological identification or, if gene sequence data were used, comparisons were often made with wrongly applied names. Colletotrichum gloeosporioides was recently epitypified so that living cultures and sequence data are, for first time available for comparison with fresh collections. Analysis of sequence data of 25 isolates from eight tropical fruits are compared with the C. gloeosporioides epitype. Contrary to previous understanding, none of the 25 Colletotrichum isolates from tropical fruits was C. gloeosporioides. The five gene regions used in this study resolved Colletotrichum asianum, C fructicola, C. horii, C. kahawae and C. gloeosporioides in the 'gloeosporioides' complex as distinct phylogenetic lineages with high statistical support. Some other likely novel species in the "gloeosporioides" complex and C. siamense, however, received only moderate or low support and further studies are needed to clarify their phylogenetic affinities and taxonomic placements. Cultural, conidial and appressorial characters can be used to differentiate taxa into species complexes, but cannot separate species within a complex. This discovery will have significant impacts on many aspects of plant pathology, pathogen diagnosis, quarantine decisions, plant breeding, and plant disease management and control and these are discussed. © 2010 Kevin D. Hyde.