Relationships of Ceratocystis fimbriata Isolates from Colombian Coffee-Growing Regions Based on Molecular Data and Pathogenicity

One of the most important diseases that reduce the profitability of coffee plantations in Colombia is coffee tree canker. This disease, caused by Ceratocystis fimbriata, has increased in severity and incidence in recent years, resulting in substantial losses to resource-poor farmers. The aim of this investigation was to consider the relatedness of C. fimbriata isolates from different Colombian coffee-growing regions, and thus to provide a foundation for future development of resistant coffee varieties. Fifty isolates from 11 provinces were characterized based on morphology and pathogenicity. In addition, isolates were compared using restriction fragment length polymorphisms (RFLPs) and random amplified polymorphic DNA (RAPD) markers. DNA sequence comparisons for the internal transcribed spacer (ITS) region, Mat-2 HMG Box and partial b-tubulin gene, were also made. The results of all comparisons clearly showed that Colombian isolates of C. fimbriata are highly variable. All molecular parameters used for these comparisons also showed that C. fimbriata isolates from Colombia reside in two major phylogenetic lineages. We believe that one of these lineages represent C. fimbriata sensu stricto and the other, a new taxon that needs further characterization. Isolates had different levels of pathogenicity on coffee, with some causing death of more that 90% and others killing <5% of inoculated plants. There was also a clear pattern of distribution of the most pathogenic strains within coffee-growing areas.