Genic introgression from an invasive exotic fungal forest pathogen increases the establishment potential of a sibling native pathogen

Significant hybridization between the invasive North American fungal plant pathogen Heterobasidion irregulare and its Eurasian sister species H. annosum is ongoing in Italy. Whole genomes of nine natural hybrids were sequenced, assembled compared with those three genotypes each two parental species. Genetic relationships among their level admixture determined. A multi-approach pipeline was used to assign introgressed genomic blocks Alleles that from associated pathways putatively related saprobic processes, while alleles native mainly linked gene regulation. There no overlap allele categories directions. Phenotypic experiments documented a fitness increase characterized by introgression species, supporting hypothesis results adaptive introgression. Conversely, into exotic appeared be driven selection on genes favoring genome stability. Since specific increased invasiveness latter we propose invasions may co-occurring: first one second belonging Given represents threat European forests, monitoring programs need track not only forest stands, but also genotypes.