ISHS Acta Horticulturae 834: III International Late Blight Conference
POPULATION STRUCTURE OF PHYTOPHTHORA INFESTANS IN THE VENEZUELAN ANDES (2004-2007) |
| Authors: | A. Briceño, M. San Román, M. Moreno, G. Fermin, L. Cedeño, K. Quintero, H. Pino |
| Keywords: | mating type, microsatellites, mitochondrial haplotype, potato, potato late blight |
| Abstract:
During the years 2004-2007, samples of Phytophthora infestans were collected from 84 potato farms in the Andean states of Mérida, Táchira and Trujillo, the main potato producing region of Venezuela. At least one sample from each of 84 fields (production units) was morphologically and molecularly characterized using standard methods for mating type (PCR and mating with reference strains), mitochondrial haplotype and a few microsatellites. Some isolates were also tested for metalaxyl resistance. A subset (12) was also analyzed for sequence variability of nuclear and mitochondrial genes (  -tubulin, intron Ras, ras, cox1, and ITS45). Data on potato variety, use of fungicides and disease management were also collected.
This assessment of the P. infestans population in Venezuela indicates a high degree of homogeneity.
All but one (self fertile) isolate were of the A1 mating type.
All but one isolate were of the Ia mitochondrial haplotype.
The exception, an IIa haplotype, also showed differences in terms of the SSR loci.
The P. infestans population from Venezuela seems to be composed of few lineages apparently not present in Colombia.
Reasons that may explain the isolation of the P. infestans population in Venezuela are discussed.
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