Isolation, identification, and biocontrol efficacy determination of Trichoderma spp. on grains

Abstract:

[Background] Grains are easily contaminated by pathogenic fungi and toxigenic fungi during the growth, harvest, and storage stages, which results in serious losses. Practices and studies have proved that the pathogenic fungi of plants can be controlled effectively by Trichoderma species. [Objective] To identify and screen the strains for the biocontrol of Trichoderma on grains and develop biocontrol fungicides for ensuring grain security.[Methods] In this study, 35 strains of Trichoderma were isolated from grains. They were identified based on both multi-gene phylogenetic relationship and morphological characteristics. Plate confrontation experiments were conducted to select the strains with antagonistic effects on common deleterious fungi. [Results] Eight species of Trichoderma were identified, including Trichoderma afroharzianum, Trichoderma asperelloides, Trichoderma amoenum, Trichoderma paratroviride, Trichoderma obovatum, Trichoderma longibrachiatum, Trichoderma orientale, and Trichoderma atroviride. The antagonistic assay demonstrated that these eight Trichoderma species had antagonism on 10 deleterious fungal species from grains. The antifungal efficacy of T. afroharzianum and T. longibrachiatum was better than that of other species. The a91 strain of T. afroharzianum showed the best antifungal efficacy, with the inhibition rates more than 65% against 9 deleterious fungal species. [Conclusion] The Trichoderma strains screened out in this study have great application potential for biocontrol and strong inhibitory effect on common pathogenic fungi and toxigenic fungi isolated from grain crops.