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Hoewel oömyceten nog maar kortgeleden het genomica-tijdperk zijn binnengetreden hebben de nieuwe ‘-omics’-technieken al geleid tot een overvloed aan kwantitatieve data. Vergelijkende en geïntegreerde genomica is cruciaal om deze schatkist met data te ontsluiten. In het proefschrift ‘Exploring Evolution and Biology of Oomycetes: Integrative and Comparative Genomics’ zijn met succes de eerste stappen gezet om deze data te gebruiken om zodoende de evolutie en biologie van oömyceten verder te ontrafelen en dit heeft reeds geleid tot waardevole nieuwe inzichten.

Hoewel oömyceten nog maar kortgeleden het genomica-tijdperk zijn binnengetreden hebben de nieuwe ‘-omics’-technieken al geleid tot een overvloed aan kwantitatieve data. Vergelijkende en geïntegreerde genomica is cruciaal om deze schatkist met data te ontsluiten. In het proefschrift ‘Exploring Evolution and Biology of Oomycetes: Integrative and Comparative Genomics’ zijn met succes de eerste stappen gezet om deze data te gebruiken om zodoende de evolutie en biologie van oömyceten verder te ontrafelen en dit heeft reeds geleid tot waardevole nieuwe inzichten.

The taxonomic class of oomycetes contains numerous pathogens of plants and animals but is related to nonpathogenic diatoms and brown algae. Oomycetes have flexible genomes comprising large gene families that play roles in pathogenicity. The evolutionary processes that shaped the gene content have not yet been studied by applying systematic tree reconciliation of the phylome of these species. We analyzed evolutionary dynamics of ten Stramenopiles. Gene gains, duplications, and losses were inferred by tree reconciliation of 18,459 gene trees constituting the phylome with a highly supported species phylogeny. We reconstructed a strikingly large last common ancestor of the Stramenopiles that contained ∼10,000 genes. Throughout evolution, the genomes of pathogenic oomycetes have constantly gained and lost genes, though gene gains through duplications outnumber the losses. The branch leading to the plant pathogenic Phytophthora genus was identified as a major transition point characterized by increased frequency of duplication events that has likely driven the speciation within this genus. Large gene families encoding different classes of enzymes associated with pathogenicity such as glycoside hydrolases are formed by complex and distinct patterns of duplications and losses leading to their expansion in extant oomycetes. This study unveils the large-scale evolutionary dynamics that shaped the genomes of pathogenic oomycetes. By the application of phylogenetic based analyses methods, it provides additional insights that shed light on the complex history of oomycete genome evolution and the emergence of large gene families characteristic for this important class of pathogens.

The taxonomic class of oomycetes contains numerous pathogens of plants and animals but is related to nonpathogenic diatoms and brown algae. Oomycetes have flexible genomes comprising large gene families that play roles in pathogenicity. The evolutionary processes that shaped the gene content have not yet been studied by applying systematic tree reconciliation of the phylome of these species. We analyzed evolutionary dynamics of ten Stramenopiles. Gene gains, duplications, and losses were inferred by tree reconciliation of 18,459 gene trees constituting the phylome with a highly supported species phylogeny. We reconstructed a strikingly large last common ancestor of the Stramenopiles that contained ∼10,000 genes. Throughout evolution, the genomes of pathogenic oomycetes have constantly gained and lost genes, though gene gains through duplications outnumber the losses. The branch leading to the plant pathogenic Phytophthora genus was identified as a major transition point characterized by increased frequency of duplication events that has likely driven the speciation within this genus. Large gene families encoding different classes of enzymes associated with pathogenicity such as glycoside hydrolases are formed by complex and distinct patterns of duplications and losses leading to their expansion in extant oomycetes. This study unveils the large-scale evolutionary dynamics that shaped the genomes of pathogenic oomycetes. By the application of phylogenetic based analyses methods, it provides additional insights that shed light on the complex history of oomycete genome evolution and the emergence of large gene families characteristic for this important class of pathogens.