Solid substrate bioassay to evaluate impact of Trichoderma on trichothecene mycotoxin production by Fusarium species.

摘要

Ability of non-toxigenic Trichoderma isolates to inhibit trichothecene synthesis by Fusarium spp. was studied using rice as a model substrate. Trichoderma atroviride and T. longibrachiatum were examined in dual culture bioassays with 2 isolates of Fusarium graminearum and 2 of F. culmorum (representing 3 chemotypes). Trichoderma isolates were able to reduce Fusarium synthesis of the 5 examined trichothecenes (nivalenol, deoxynivalenol (DON), 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol and fusarenone X) by >95%. When Trichoderma isolates were inoculated on autoclaved-rice cultures of Fusarium containing known amounts of the 5 trichothecenes, concn. of DON increased in cultures of a F. culmorum isolate after inoculation of Trichoderma isolates, whereas decreases in trichothecene concn. were noted in other cases. Overall results indicate that Trichoderma isolates have potential for biocontrol of toxigenic Fusarium and achieve significant reductions in synthesis of mycotoxins such as DON, nivalenol and their acetylated derivatives in wheat and other cereals.