Antifungal activity and active compound identification of Myrothecium spp. against grape anthracnose and gray mold

Grape anthracnose and gray mold, caused by Elsinoë ampelina and Botrytis cinerea, are devastating fungal diseases resulting in remarkable loss to grapevine production. In this study, the biological control potential of three strains of Myrothecium spp. against E. ampelina and B. cinerea was investigated. The hypha and culture filtrate of Myrothecium spp. exhibited an antifungal activity against E. ampelina. M. cinctum, M. roridum, and Albifimbria verrucaria exhibited biocontrol efficacy of 62.82 %, 80.26 %, and 89.58 % for grape anthracnose in V. vinifera 'Thompson seedless' leaves at 6 days post-inoculation (dpi), respectively. Furthermore, A. verrucaria significantly reduced the disease index of gray mold by 41.56 % and 49.38 % in V. vinifera 'Thompson seedless' leaves at 4 dpi. The relative biomass of B. cinerea was significantly decreased after treatment with culture filtrate of A. verrucaria in berries at 2 and 4 dpi. Combining the inhibition assay of the conidial germination of B. cinerea, the active compounds of A. verrucaria were purified using column chromatography, thin-layer chromatography, and high-performance liquid chromatography. One active compound was identified as verrucarin A by nuclear magnetic resonance. Verrucarin A remarkably inhibited the mycelial growth of E. ampelina, Botrytis cinerea, and Coniella vitis at concentrations of 20 μg/mL. The disease incidence of gray mold was significantly reduced by 10.49 % in V. vinifera 'Red Globe' berries after treatment with verrucarin A at 5 dpi compared with control, and the biocontrol efficacy reached 66.22 %. This study demonstrates that Myrothecium spp. could be developed as an effective biocontrol agent against grape anthracnose and gray mold.