Sm. Beynon et al., GENETIC-VARIATION IN THE COFFEE BERRY DISEASE PATHOGEN, COLLETOTRICHUM-KAHAWAE, Physiological and molecular plant pathology, 46(6), 1995, pp. 457-470
The genetic variation among 25 isolates of Colletotrichum kahawae from
widely distributed sources in Africa was studied. Pathogenicity tests
on hypocotyls of Coffea arabica cv. Caturra, distinguished a moderate
ly aggressive and a highly aggressive group of isolates. Analysis of r
estriction fragment length polymorphisms (RFLPs) with a Fusarium oxysp
orum ribosomal DNA repeat from the plasmid pDG312 clearly distinguishe
d C. kahawae from the other two species, C. gloeosporioides and C. acu
tatum, commonly found with the pathogen on coffee. However, no polymor
phisms were detected amongst the isolates of C. kahawae. Despite this
apparent uniformity in probed DNA, complementation tests with mutants
in the nitrate assimilation pathway revealed at least five vegetative
compatibility groups (VCGs). This apparent lack of correlation between
the RFLP analysis and the variation predicted from the vegetative com
patibility grouping may indicate the existence of a teleomorphic stage
of the pathogen, which is as yet undiscovered.