Human associated introduction of pathogens and consequent invasions are very evident in areas where no related organisms existed before. In areas where related but distinct populations or closely related cryptic species already exist, the invasion process is much harder to unravel. In this study, the population structure of the Eucalyptus leaf pathogen Teratosphaeria nubilosa was studied within its native range in Australia, including both commercial plantations and native forests. A collection of 521 isolates from across its distribution was characterized using eight microsatellite loci, resulting in 112 multilocus haplotypes (MLH). Multivariate and Bayesian analyses of the population conducted in STRUCTURE revealed three genetically isolated groups (A, B and C), with no evidence for recombination or hybridization among groups, even when they co-occur in the same plantation. DNA sequence data of the ITS (n=32), β-tubulin (n=32) and 27 anonymous loci (n=16) were consistent with microsatellite data in suggesting that T. nubilosa should be considered as a species complex. Patterns of genetic diversity provided evidence of biological invasions by the pathogen within Australia in the states of Western Australia and New South Wales, and helped unravel the pattern of invasion beyond Australia into New Zealand, Brazil and Uruguay. No significant genetic differences in pathogen populations collected in native forests and commercial plantations were observed. This emphasizes the importance of sanitation in the acquisition of nursery stock for the establishment of commercial plantations.

individual_by_individual_sampling_location_and_genotypesThis file contains individual by individual information about sampling and microsatellite Multilocus Haplotypes. This includes Country, State, locality, site number sensu table 1, whether the isolate was collected on native forest or commercial plantation, host and GPS coordinates. Because 112 MLHs were observed on the populations the internal code for MLHs (#MLH) is provided. Three genetic groups were identified using Structure, this info is also presented individual by individual. The isolate name and the culture collection number (CMW) of the Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, South Africa is also presented individual by individual. Finally the allele for each of the eight microsatellite loci (MN-1, MN-2, MN-3, MN-7, MN-9, MN-10, MN-11 and MN-14) amplified using the fluorescently labelled T. nubilosa-specific primers developed by Hunter et al. (2006) are provided.clon_corrected_datasetThis file contains the 112 MLHs (clone corrected) used for population analyses