Study On Control Of Soil-borne Disease Of Vegetable Crops With Biocontrol Agents Of Trichoderma Spp. And Their Transformation With Gfp Genes

Soil borne diseases of vegetables were distributed over the world and can cause severe damage. Biocontrol have been proved to be an effective alternative to manage this kind of disease. Most studies have focused on biocontrol of soil borne diseases with Trichoderma spp. and many Trichoderma products were comercialized at home and abroad. However short shelve time limited their pratical use. Moreover, most of them are single Trichoderma strain products, which is not steady in the application. .In our previous studies, T. harzionum strain TC₃ and NF₉, T. virens strain TY009 have showed antagonistic effect on soil borne pathogens. The biocontrol potential of the mixture agents of the three strains of Trichoderma against vegetable soil-borne diseases was evaluated in this study.The growing conditions of mixtured Trichoderma strains were also evaluated in different treatments. It is showed that it was good for mycelial growth and spore germination at the ration 6: 4 (W: W) of wheat bran and rice husk, rice Bran and rice husk; at ration 4: 6 (W: W) of wheat bran and rice, rice bran and rice. In addition, water capacity in substrate between 1.2: 1～1.4: 1 and controled light 12 h black 12 h was the best for growth of spore mixtures of Trichoderma.The biocontrol efficacy of the spore mixtures of Trichoderma in greenhouse was also determined. The result showed that damping off of cucumbers, damping off of eggplants, sclerotium disease of lettuce, fusarium wilt of cucumber and black shank disease of tobacco were suppressed by 75.5%, 55.0%, 59.0%.The results also indicated that the better control for fusarium wilt of cucumber and black shank disease of tobacco. In addition, the mixture agent of Trichoderma showed better effect on control of fusarium wilt of cucumber that that of single application with 3 Trichoderma strains alone.In order to observe colonization of the mixture agent of Trichoderma, we constructed the vectors containing gfp gene for its expression in Trichoderma strain and the transformation of protoplasts also were conducted.