Aggressiveness and Genetic Diversity of Hemileia vastatrix During an Epidemic in Colombia

Abstract

Since 2008, Colombia has been experiencing an epidemic of the coffee rust Hemileia vastatrix. The altitude range of the disease has expanded, and nursery and young plants that were usually not attacked by the disease are now significantly affected. To determine whether this new epidemic has been caused by a new pathogenic isolate, the molecular diversity of the pathogen causing the epidemic in different regions of the country was assessed, using AFLP molecular markers on isolates collected from coffee fields prior and after the year 2008. We also evaluated the aggressiveness of isolates collected from diverse coffee-producing areas and from different coffee genotypes. Isolates collected before and during the present epidemic were quite similar both genetically and with regard to their aggressiveness. Out of a total of 349 fragments amplified from 6 AFLP primer combinations, 48 (13.2%) were polymorphic and only 18 were unique among H. vastatrix isolates representative of pre-2008 and post-2008 epidemic populations. We conclude that the epidemic was caused by the excessive rainfall that has occurred in Colombia since 2006 and that extended to 2011 and not by the arrival of a new isolate of the pathogen or a change in virulence of the species present in the country.

Genetic diversity and structure of Hemileia vastatrix populations on Coffea spp.

“…In previous studies, six AFLP primer combinations were evaluated for H . vastatrix , detecting 349 fragments, of which only 13·2% were polymorphic (Rozo et al ., ). On the other hand, 77% of unique genotypes in 120 isolates of H .…”

Identification of a major QTL for adult plant resistance to coffee leaf rust (Hemileia vastatrix) in the natural Timor hybrid (Coffea arabica x C. canephora)

“…In a recent report, Rozo et al. () emphasized the importance of meteorological conditions on the success of the rust–coffee interaction and then on the development of epidemic disease. In this study, only data from the rust epidemic in August 2009 (R_aug09) together with ALesion and AUDC allowed us to detect genetic expression of rust resistance in the F 2 segregating population.…”

Manganese Phosphite in Coffee Defence against Hemileia vastatrix, the Coffee Rust Fungus: Biochemical and Molecular Analyses

“…Coffee rust, caused by the fungus Hemileia vastatrix Berk and Br, is the major coffee disease, occurring in almost all coffee-producing countries in the world (Rozo et al 2012). The disease can cause a 35-50 per cent yield reduction, if no control action is taken (Silva et al 2006).…”