Difference in pathogenicity and genetic variability among isolates of Biscogniauxia mediterranea from Quercus suber in Tunisia

Abstract

Biscogniauxia mediterranea has long been recognized as the causal agent of charcoal canker disease of Quercus species. It has been considered to be highly involved in cork oak decline in the Mediterranean region. In this study, a collection of B. mediterranea strains was isolated from declining cork oak trees in three cork oak forests in Tunisia. Among them, nine representative isolates were subjected to genetic polymorphism analysis based on ITS and tef1-α sequences showing a highly significant haplotype diversity. Pathogenicity tests of these isolates revealed a highly pathogenic effect towards stems which differed significantly between isolates. Although, they were less aggressive toward leaves. Nevertheless, the Mantel test indicated the absence of a significant correlation between the genetic and pathogenic variability.