The Study On The Colonizing Ability Of Trichoderma Viride H6-L4 And Its Biological Control Against Banana Vascular Wilt

Banana panama wilt has already become one of the main disease in banana production, which is induced by Fusarium oxysporum f.sp. cubense infect into vascular bundle of host caused many economic losses in Chinese banana ondustry because its pathogen transmits rapidly. Trichoderma viride H6-L4 from our screening research can inhibit Fusarium oxysporum f.sp. cubense.In this paper, we studied the inhibition mechanism and induced resistance for Fusarium oxysporum f.sp. cubense of Trichoderma viride H6-L4. The fermentation, insecticide resistance and survival ability in soil of Trichoderma viride H6-L4 has been studied through the pot culture. The results will be showed in the following.1. The impact of various factors on Trichoderma viride H6-L4 mycelium had been determined in plate incorporation assay and reduction at different times. The results indicated that influence order of the impact of various factors on Trichoderma viride H6-L4 mycelium is.-Carbon source> inorganic salts> carbon and nitrogen ratio> nitrogen sources. The optimal recipe of Trichoderma viride H6-L4 mycelial growth and sporulationare as the following suger 20g, NH4NO38g, K2SO4 1g, KH2PO42g, water 1000mL, optimal tempreture is 28℃, pH=6. The quantity of spore is 1.67×109cfu/g in this optimal conditions after fermented five days. The bacteriostatic ability of H6-L4 fermentation supernatant would be the strongest after fermented five days. The optimal fermentation conditions of Trichoderma viride H6-L4 are as following pathogen 15%, pH=6, optimal tempreture is 28℃.2. We obtained the results of the antibacterial activity stability of Trichoderma viride H6-L4 metabolites and its extracts by fermentation, compare the size of the zone of inhibition. We obtained that Trichoderma viride H6-L4 can produce volatile and non-volatile substance, they all can inhibit the growth of Fusarium oxysporum f.sp. cubense. The antibacterial activity of fermentation supernatant was significantly higher after treated in the high temperature inactivation treatment than which treated after ultrasonic broken deal. The effect of suppressing can be the strongest when the active ingredients of Trichoderma viride H6-L4 fermentation broth is in the condition of the temperature below 80℃, pH=6-7. The best prevent effect on Fusarium oxysporum f.sp. cubense by extracts of conidia is 51.71% which extracted by NaOH.3. We directed the activities of enzymes which relate to induced resistance of banana seeding after applied Trichoderma viride H6-L4 has been dominant increased, such as POD, PAL, CAT, SOD and PPO. The study of the root cell viability detection of banana seedlings shows that the Trichoderma viride H6-L4 and the interaction between the root system can effectively improve plant disease resistance.4. We determined the colonization of Trichoderma viride H6-L4 under different conditions in the soil, and its prevention effects in pot and residential soil on Fusarium oxysporum f.sp. cubense. By studing the effects of Trichoderma viride H6-L4 on colonization and disease prevention, we know that the influence order of the effects of Trichoderma viride H6-L4 on colonization and disease prevention is:sand> nutritive soil> loess> vegetable soil. The colonization ability of Trichoderma viride H6-L4 in the soil with plant is better than that in the soil without plants. The most conducive conditions of plant food for the the reproduction of Trichoderma viride H6-L4 is Urea 1.6‰, Batian world through fertilizer 0.8 %o, the organic potassium Po 6.4‰, OPAL humic acid the organic mineralization activity Chong fertilization 6.4‰. The control effect of Trichoderma viride H6-L4 on Fusarium oxysporum f.sp. cubense can be 85.46% when the Trichoderma viride H6-L4 broth at 50 times. The disease prevention control efficiency of Trichoderma viride H6-L4 broth would be better at 75.23% when sincere it into soil first. The control efficiency is not very high in the residential soil, it can only be 42.12% after 60 days.5. We determined the grobacterium-mediated transformation of Trichoderma viride H6-L4 green fluorescent marker, the result is that the stability of transformation of Trichoderma viride H6-L4 is so high, but the conversion efficiency is not very high. But the conditions for the more conducive of H6-L4 transformed also requires further exploration.