Trichoderma harzianum sensu lato TSM39: A wheat microbiome fungus that mitigates spot blotch disease of wheat (Triticum turgidum L. subsp. durum) caused by Bipolaris sorokiniana

• Published in: Biological control 2022-11, Vol.175, p.105055, Article 105055
• Main Authors: Villa-Rodriguez, Eber, Lugo-Enríquez, Cristina, Ferguson, Shaun, Parra-Cota, Fannie Isela, Cira-Chávez, Luis Alberto, de los Santos-Villalobos, Sergio
• Format: Article
• Language: English
• Subjects: Biocontrol; Biological control; Biopesticide; Cochliobolus sativus; Trichoderma; Yaqui valley
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1016/j.biocontrol.2022.105055

[Display omitted] •Trichoderma harzianum sensu lato TSM39 is a promising biocontrol agent of B. sorokiniana.•Trichoderma harzianum sensu lato TSM39 inhibits B. sorokiniana by mycoparasitism.•The chitinolytic system of strain TSM39 is induced by cellular components of B. sorokiniana.•Trichoderma harzianum sensu lato TSM39 can be produced by solid-state fermentation. Bipolaris sorokiniana - the causal agent of wheat spot blotch - is an emerging phytopathogenic fungus in the Yaqui Valley, Sonora, Mexico. At present, its control relies on the use of harmful chemicals, partly due to the lack of effective alternatives. Thus, this work aimed to identify and characterize indigenous wheat-associated fungal strains with biocontrol capacity against B. sorokiniana that can be integrated into control strategies for spot blotch management. Out of 59 fungal strains evaluated, we identified 5 strains with antagonistic activity against B. sorokiniana by dual confrontation assay, and these were taxonomically assigned as Trichoderma harzianum sensu lato (strains TSM39 and TSO39), Aspergillus terreus (strains TRQ89 and TRQ93), and Aspergillus nidulans (strain TRQ83) based on phylogenetic analysis using the ITS region of the rRNA cistron. Trichoderma harzianum TSM39 showed interesting biological control traits (i.e., strong antagonistic activity, high growth rate, non-cytotoxicity) and its application to wheat plants - under highly conducive conditions for spot blotch outbreak- resulted in a significant reduction of disease severity. In vitro experiments revealed that the chitinolytic system of strain TSM39 responds to B. sorokiniana lysates (signals), which could have potential biotechnological applications to improve its biocontrol activity. Additionally, a solid-state fermentation system was successfully established for spore production of strain TSM39. Taken together, Trichoderma harzianum sensu lato TSM39 is a biocontrol agent against B. sorokiniana with the potential to be integrated into spot blotch management strategies and contribute to the sustainability of the region.