Background: Asian soybean rust (SBR) caused by Phakopsora pachyrhizi
Syd. & Syd., is one of the main diseases affecting soybean and
has been reported as one of the most economically important fungal
pathogens worldwide. Knowledge of the genetic diversity of this fungus
should be considered when developing resistance breeding strategies. We
aimed to analyze the genetic diversity of P. pachyrhizi combining
simple sampling with a powerful and reproducible molecular technique.
Results: We employed Amplified Fragment Length Polymorphism (AFLP)
technique for the amplification of P. pachyrhizi DNA extracted from
naturally SBR-infected plants from 23 production fields. From a total
of 1919 markers obtained, 77% were polymorphic. The high percentage of
polymorphism and the Nei's genetic diversity coefficient (0.22)
indicated high pathogen diversity. Analysis of molecular variance
showed higher genetic variation within countries than among them.
Temporal analysis showed a higher genetic variation within a year than
between years. Cluster, phylogenetic and principal co-ordinate analysis
showed that samples group by year of collection and then by country
sampled. Conclusions: The study proposed combining a simple
collection of urediniospore with a subsequent analysis by AFLP was
useful to examine the molecular polymorphism of samples of P.
pachyrhizi collected and might have a significant contribution to the
knowledge of its genetic diversity. Also, AFLP analysis is an important
and potent molecular tool for the study of genetic diversity and could
be useful to carry out wider genetic diversity studies