Genetic Diversity of the Population of Phytophthora infestans in Hungary

Abstract

A total of 123 isolates of Phytophthora infestans were recovered from 43 commercial fields and allotments of potato and tomato in Hungary. Isolates were characterised for mating type, response to metalaxyl, isozyme genotype at glucose-6-phosphate isomerase (Gpi) and peptidase A (Pep) loci, nuclear DNA fingerprint with probe RG57 and mitochondrial haplotype. Both mating types were detected in 8 potato and 3 tomato fields. The frequency of A1 and A2 were 47.5% and 52.5% on potato and 60.5% and 39.5% on tomato. More than sixty per cent of the whole population were resistant (31.1%) or responded intermediately (30.2%) to the fungicide metalaxyl in vitro. All isolates were monomorphic at the Gpi locus (100/100), but four allele combinations 100/100 (33%), 96/100 (28%), 96/96 (31%) and 83/96 (8%) were found at the Pep locus. Genotype Pep 83/96 is rare in Europe and all isolates with this allele combination were of A1 mating type and Ia mitochondrial haplotype. As in other European populations, only two of the f...