Characterization of genomes and putative biological control mechanisms of novel Californian grapevine-isolated Trichoderma strains to combat trunk pathogens including Xylella fastidiosa

Authors: Wallis, Christopher

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Grapevines encounter numerous trunk diseases that can reduce yields and cause premature decline, including fungal pathogen-caused canker diseases and the bacterium Xylella fastidiosa-caused Pierce’s disease. Management options for these diseases consist mostly of pesticide applications including fungicides to reduce fungal pathogens and insecticides to reduce vectoring insects that spread X. fastidiosa. However, frequent use has resulted in pesticide resistance, and long-term sustainable management options are needed. Thus, research was initiated to discover novel biological control agents to protect grapevines. Multiple Trichoderma spp. isolates were obtained from Californian vineyards. These fungi were first screened for capacity to limit pathogen growth in co-plating assays, and then screened for ability to produce antibiotics via amended agar assays. Greenhouse studies then were performed to examine whether prior inoculation with promising Trichoderma strains could reduce pathogen infection and disease symptom development. These strains also were evaluated as pruning wound protectants in a field trial. Results from these experiments identified at least eight novel Californian Trichoderma strains with good biological control potential against fungal pathogens or X. fastidiosa. Next generation sequencing was performed on these strains and revealed that these strains were one of four different Trichoderma species: T. asperellum, T. harzianum, T. reesei, and an uncharacterized Trichoderma species. Of these, the T. harzianum strains appeared most effective at combating pathogen infections, whereas the T. reesei strain appears best at producing antimicrobial compounds. Taken together, these results demonstrated the potential of novel Trichoderma strains to improve management of grapevine trunk diseases and Pierce’s disease.