Neofusicoccum parvum: Genetic uniformity and invasive spread in the Western Balkans

During the past decade, various forest and ornamental trees and shrubs in the Western Balkans region have been damaged by outbreaks of canker and die-back disease. These have been caused by species of the Botryosphaeriaceae, including the globally distributed Neofusicoccum parvum. The aims of this study were to determine genetic diversity and structure between populations of N. parvum from Serbia and Montenegro. This was achieved using DNA sequence data of the internal transcribed spacer (ITS) rDNA, translation elongation factor 1-alpha (TEF 1-α), β-tubulin-2 (BT2) and microsatellite markers. The study included populations of N. parvum from Continental (CR) and Mediterranean (MR) climatic regions. Neofusicoccum parvum was shown to have a low gene and genotypic diversity across the region. The CR and MR populations of N. parvum were found to be partially differentiated from each other and no genotypes and only a single haplotype were shared between the two regions. The low genetic diversity of N. parvum on non-native trees and comparison of populations from other regions of the world suggests that this species has most likely been introduced into Western Balkans, possibly through the movement of diseased plants. Neofusicoccum parvum populations appear to have been influenced by recent founder events from an unknown source population.