Résumé
Background: Molecular typing of pathogen populations is an important tool
for the development of effective strategies for disease control. Diverse
molecular markers have been used to characterize populations of
Xanthomonas axonopodis pv. manihotis (Xam), the main bacterial pathogen of
cassava. Recently, diversity and population dynamics of Xam in the
Colombian Caribbean coast were estimated using AFLPs, where populations
were found to be dynamic, diverse and with haplotypes unstable across
time. Aiming to examine the current state of pathogen populations located
in the Colombian Eastern Plains, we also used AFLP markers and we
evaluated the usefulness of Variable Number Tandem Repeats (VNTRs) as new
molecular markers for the study of Xam populations. Results: The
population analyses showed that AFLP and VNTR provide a detailed and
congruent description of Xam populations from the Colombian Eastern
Plains. These two typing
strategies clearly separated strains from the
Colombian Eastern Plains into distinct
populations probably because of
geographical distance. Although the majority of analyses were congruent
between typing markers, fewer VNTRs were needed to detect a higher number
of genetic populations of the pathogen as well as a higher genetic flow
among sampled locations than those detected by AFLPs. Conclusions: This
study shows the advantages of VNTRs over AFLPs in the surveillance of
pathogen populations and suggests the implementation of VNTRs in studies
that involve large numbers of Xam isolates in order to obtain a more
detailed overview of the pathogen to improve the strategies for disease
control.