D. Sicard et al., GENETIC DIVERSITY AND PATHOGENIC VARIATION OF COLLETOTRICHUM-LINDEMUTHIANUM IN THE 3 CENTERS OF DIVERSITY OF ITS HOST, PHASEOLUS-VULGARIS, Phytopathology, 87(8), 1997, pp. 807-813
Population subdivision of Colletotrichum lindemuthianum, the causal ag
ent of anthracnose, was studied in three regions located in three cent
ers of diversity of its host, Phaseolus vulgaris. Random amplified pol
ymorphic DNA (RAPD) markers, restriction endonuclease analysis of the
amplified ribosomal internal transcribed spacer region, and virulence
on a set of 12 cultivars were used to assess the genetic diversity of
C. lindemuthianum strains isolated in Mexican, Ecuadorian, and Argenti
nean wild common bean populations. The three regions were significantl
y differentiated for molecular markers. For these markers, Mexico was
the most polymorphic and the most distant from Ecuador and Argentina.
The majority of the RAPD alleles present in Ecuador and Argentina were
found in Mexico, suggesting that Andean populations have been derived
from the Mesoamerican center. Pathogenicity tests on a set of 12 cult
ivars showed that all but one of the Mexican strains were virulent exc
lusively on Mesoamerican cultivars. Argentinean strains were virulent
preferentially on southern Andes cultivars, and the Ecuadorian strains
, except for one strain, were avirulent on all cultivars. These result
s suggest an adaptation of strains on cultivars of the same geographic
origin. Thus, based on molecular and virulence markers, C. lindemuthi
anum strains isolated from wild common bean populations were divided i
nto three groups corresponding to host gene pools.