Molecular and phenotypic characterisation of Phaeomoniella chlamydospora isolates from the demarcated wine region of Dão (Portugal)

Abstract

Sixty-eight isolates of Phaeomoniella chlamydospora obtained from symptomatic esca and Petri disease grapevines, obtained mostly within the Portuguese Dão appellation, were investigated regarding their phenotypic and molecular diversity, in order to determine intraspecific variability and population structure. Phenotypic features such as texture, colour, growing margin zonation, hyphal morphology and diameter growth were evaluated. Molecular characterization was performed through the sequencing of the total ITS region and molecular analyses were used to infer phylogenetic relationships, using the Maximum Likelihood approach. Isolates were divided into two groups, by both phenotypic and molecular analysis, but no clear correspondence was found between the two approaches. Nevertheless, both phenotypic and molecular analysis revealed a strong homogeneity among all isolates, despite their geographical origin, year of isolation and scion/rootstock combination, therefore supporting the clonal reproduction strategy described for this species.