Isolation,identification of Trichoderma hamatum and determination of its antibacterial activity on Colletotrichum capsici and Ustilago coicis

【Objective】 The purpose of the study was to isolate and identify beneficial strains of Trichoderma spp., and to explore their inhibitory effects on Colletotrichum capsici and Ustilago coicis, so as to provide a theoretical support for the development and utilization of Trichoderma spp. and the biocontrol of pepper anthracnose and adlay smut disease. 【Method】 The beneficial strains of Trichoderma spp. were isolated and identified from the rhizosphere soil of Houttuyniae herba by tissue isolation method. Its taxonomic status was determined by morphology and ribosomal transcription spacer (ITS) sequencing. The inhibitory effects of Trichoderma spp. mycelium,small molecule metabolites and volatile components on C. capsici and U.coicis were tested by the two-point confrontation method,growth rate method and flat plate buckle method.【Result】 A single strain was isolated and purified from the rhizosphere soil of H. herba by tissue isolation method and recorded as ZQ202104. The results of morphology characteristics and molecular biology identification showed that strain ZQ202104 was T. hamatum. Under the confrontation culture,strain ZQ202104 had inhibitory effect on the growth of C. capsici and U.coicis,and the inhibition rates were 59.40% and 74.01% respectively. The results of growth rate assay showed that strain ZQ202104 could inhibit the growth of C. capsici and U.coicis well when the filtrate was added at the amounts of 2,4 and 6 mL,with the inhibition rates of 57.57%,60.60% and 65.15% against C. capsici and 71.42%,82.85% and 85.71% against U.coicis,respectively. When fermented for 9 d,the bacteriostatic activity of strain ZQ202104 sterile fermentation broth showed the highest inhibition rate on C. capsici(35.09%). When the fermentation was performed for 15 d,the inhibition rate on U.coicis was the highest(68.00%). The volatile components of strain ZQ202104 had inhibitory effects on the growth of C. capsici and U.coicis,and the inhibition rates were 47.29% and 82.95% respectively.【Conclusion】 The mycelium,small molecule metabolites and volatile components of T. hamatum strain ZQ202104 isolated from the soil in the rhizosphere of H. herbahas inhibitory effects on C. capsici and U.coicis, and the growth inhibitory effect is obvious especially for U. coici. The biocontrol mechanism may be a combination of competition and antibacterial effects. Strain ZQ202104 has the potential to be developed into a bacteriostatic agent for U.coicis.