Utilizing mitochondrial genome sequences to understand population diversity among Trichoderma species

Biopesticides, including those containing various Trichoderma species, may provide improved control of fungal diseases of woody perennials including grapevines. Thus, Trichoderma isolates were obtained from grapevines in California, U.S.A., with eight strains demonstrated to provide biological control against fungal pathogens. These were determined via phylogenetic analyses to be one of six different species: Trichoderma asperellum , Trichoderma capillare , Trichoderma harzianum , Trichoderma saturnisporopsis , and two novel Trichoderma species ( Trichoderma sp. DL1–3 and Trichoderma sp. PAR10). However, little is known about strain genetic diversity. Therefore, efforts were undertaken to characterize and compare obtained mitochondrial genomes with those previously published from related Trichoderma species. For this effort, the mitochondrial genomes of T. asperellum strain TLI, T. capillare strains KC2–2 and SLO1-1, and T. saturnisporopsis strain RSI were obtained and annotated, and compared to the other Californian strains and 23 other Trichoderma species genomes. All analyzed species had the same major protein coding genes, rRNA regions, and tRNA coding sequences. Further, specific introns were observed to be associated with distinct clades within the Trichoderma genus, and these could be used to develop markers to quickly assign an unknown Trichoderma into a specific clade. Knowledge of Trichoderma mitochondrial genomes should improve understanding about this fungal species.