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Poster: Epidemiology: Population Biology Genetics


Molecular characterization and genetic diversity of Mycosphaerella fijiensis in Costa Rica using sequence based nuclear markers
J. RISTAINO (1), A. Saville (1), M. Charles (1), M. Wyatt (1), S. Chavan (1) (1) North Carolina State University, U.S.A.

Mycosphaerella fijiensis is the causal agent of black sigatoka, a devastating disease of banana that can cause 20-80% yield loss in the absence of fungicides. M. fijiensis first appeared in Honduras in 1972 and spread to the rest of the western hemisphere, including major banana production regions such as Costa Rica. In order to characterize the genetic diversity of M. fijiensis in Costa Rica, one hundred and eighteen isolates, collected from Costa Rica and Honduras between 2010 and 2014, were examined using multilocus genotyping of six loci and compared to a previously published global dataset. A total of 13 haplotypes were identified from concatenated sequences of Honduran and Costa Rican populations, six of which were unique. Outside of the Americas, Costa Rican and Honduran populations shared haplotype diversity with populations in both Oceania and Southeast Asia for all loci, in particular Australia, Futuna, Tonga, and Papua New Guinea, the latter of which has been proposed as the center of origin for both banana and M. fijiensis. The genetic similarity to both regions suggests M. fijiensis may have been introduced into Honduras and Costa Rica multiple times. Given a relatively recent introduction, subsequent admixture events are expected to increase diversity of Costa Rican populations over time.