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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #387758
Research Project: Discovery and Development of Microbial-Based Biological Control Agents for Use Against Invasive Weeds in the United States

Location: Foreign Disease-Weed Science Research

Title: Screening and assessing biological differences among oomycete-parasitic Trichoderma asperellum isolates for biological control development

Author
item Tancos, Matthew
item Thomas, Jami
item WIDMER, TIMOTHY - US Department Of Agriculture (USDA)

Submitted to: PhytoFrontiers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2022
Publication Date: 2/10/2023
Citation: Tancos, M.A., Thomas, J.L., Widmer, T.L. 2023. Screening and assessing biological differences among oomycete-parasitic Trichoderma asperellum isolates for biological control development. PhytoFrontiers. https://doi.org/10.1094/PHYTOFR-09-22-0094-SC.
DOI: https://doi.org/10.1094/PHYTOFR-09-22-0094-SC

Interpretive Summary: Trichoderma species are prevalent soil-inhabiting fungi that are commonly utilized as microbial-based biological control agents for managing plant pathogens. Trichoderma asperellum is a popular Trichoderma biopesticide due to its antagonistic activity against diverse pathogens and its ability to induce plant systemic resistance and growth. Screening diverse biological features becomes critical in selecting promising T. asperellum isolates for biological control activity and product development. In the present study, the authors screened for morphological, sporulation, and genetic differences between diverse, globally collected T. asperellum isolates previously evaluated for parasitism against the oomycete pathogen, Phytophthora ramorum. The information in this study will be applicable to other researchers who are interested in developing Trichoderma species as effective biological control agents and highlight the need to better elucidate the similarities and differences in the molecular pathology of T. asperellum isolates selected to parasitize plant pathogenic oomycetes and/or fungi.

Technical Abstract: Trichoderma are ubiquitous soil-inhabiting fungi that produce numerous extracellular proteins critical to saprophytic, mutualistic, and mycoparasitic lifestyles. Trichoderma are effective mycoparasites due to the production of diverse chitinolytic enzymes, glucanases, and proteases, which actively degrade microbial cell walls. The diversity of extracellular proteins and the unique parasitic features of Trichoderma species has resulted in their development as biological control agents for numerous plant pathogens. The objective of this study was to characterize diverse biological features important to the selection of promising oomycete-parasitic T. asperellum isolates. Nine globally collected T. asperellum isolates previously evaluated for parasitism against Phytophthora ramorum were screened for morphological and sporulation differences in regard to temperature and pH, and the prevalence of the mycoparasitism-associated chitinase gene, chi42. Sporulation and growth variability was evident between the diverse T. asperellum isolates, but a single copy of the chi42 gene was highly conserved between all isolates. Screening numerous, diverse biological features is important to the selection and development of microbial-based biological control agents, while elucidating the molecular pathology of fungal and oomycete-parasitic T. asperellum isolates will aid in future screening and selection processes.