The Bipartite Structure of the First Genome of Ampelomyces quisqualis, a Common Hyperparasite and Biocontrol Agent of PowderyMildews, May Point to Its Evolutionary Origin from Plant Pathogenic Fungi

Powderymildews are among the most important plant pathogensworldwide, which are often attacked in the field bymycoparasitic fungi belonging to the genusAmpelomyces. The taxonomy of the genusAmpelomyces is unresolved, butwell-supportedmolecular operational taxonomic units were repeatedly defined suggesting that the genus may include at least four to seven species. Some Ampelomyces strains were commercialized as biocontrol agents of crop pathogenic powdery mildews. However, the genomic mechanisms underlying theirmycoparasitismare still poorly understood. To date, the draft genome of a single Ampelomyces strain, designated asHMLAC05119, has been released. We report a high-quality, annotated hybrid draftgenome assemblyofA. quisqualis strain BRIP 72107, which, based on phylogenetic analyses, is not conspecific with HMLAC 05119. The constructed genome is 40.38Mb in size, consisting of 24 scaffolds with an N50 of 2.99Mb and 96.2% completeness. Our analyses revealed bipartite structure ofAmpelomyces genomes, whereGC-balanced genomic regions are interspersed by longer or shorter stretches ofAT-rich regions. This is also a hallmark of many plant pathogenic fungi and provides further evidence for evolutionary affinity of Ampelomyces species to plant pathogenic fungi. The high-quality genome and annotation produced here provide an important resource for future genomic studies of mycoparasitisim to decipher molecular mechanisms underlying biocontrol processes and natural tritrophic interactions.

Automated summary

Mycoparasitic fungi Ampelomyces are important for controlling plant pathogenic powdery mildews. The genomic analysis revealed the bipartite structure of Ampelomyces genomes and their evolutionary affinity to plant pathogenic fungi. The high-quality genome assembly provides a valuable resource for future studies on biocontrol mechanisms.