Genetic diversity among phytopathogenic Sclerotiniaceae, based on retrotransposon molecular markers

Abstract

Molecular marker systems have been widely used for determination, discrimination and population structure analysis in the Sclerotiniaceae. The usefulness of a new marker system iPBS, based on the sequences of reverse transcriptase primer binding sites in long terminal repeats retrotransposons, was investigated with 34 isolates of six species confirmed by species-specific markers. Six of the iPBS primers were found to produce highly polymorphic (98%) and very distinct species-specific band patterns. Each primer amplified, on average, 33.5 polymorphic bands that was sufficient for species differentiation. The polymorphism information content was 0.896, indicating better discriminating power of markers, , the Shannon’s information index was 0.438, and the genetic distance was 0.707 as average values. UPGMA cluster analysis based on retrotransposons divided all the isolates into three cluster and six sub-clusters in accordance with their species. Principal co-ordinate analysis also strongly confirmed this cluster pattern. The iPBS marker system was therefore a useful tool for evaluation of genetic variation at intra- and inter-species, and at the population levels for members of the Sclerotiniaceae. Furthermore, the iPBS markers could provide easy discrimination of Botrytis cinerea from Botrytis pseudocinerea.