木霉菌在玉米病害生物防治中的作用机制及应用(英文)

Mechanism and application of Trichoderma spp. in biological control of corn diseases

目前,世界上共有分属于10个属(T richoderma,Gliocladium,Chaetomium,Bacillus,Burkhoderia,Streptomyces and Pseudomonas,Pantoea,Enterobacter,Macrobacterium)中的微生物被试验用于玉米病害的生物防治,其中细菌14种,真菌17种,放线菌1种。国际上由木霉菌开发的生物杀菌剂和生物肥料有50余种,其中以哈茨木霉T22菌株开发的产品最为著名。目前在我国也开发出了4种木霉菌剂型(可湿性粉剂、颗粒剂、水分散粒剂和种衣剂),正式登记的木霉菌杀菌剂有7种,其中6种为可湿粉剂,1种为水分散粒剂,主要登记用于防治番茄、观赏百合、黄瓜的立枯病、猝倒病、根腐病、灰霉病、霜霉病以及小麦的纹枯病,但尚无木霉菌生物农药被登记用于防治玉米病害。以木霉菌为主要成分登记的菌肥产品有11种,其中在玉米上应用的有2种。由课题组研制的木霉菌颗粒剂和种衣剂通过土壤穴施和种子包衣可有效防治玉米茎腐病和纹枯病,其中木霉菌颗粒剂防效达65%?87%。近期研制的木霉菌可湿性粉剂对玉米小斑病的防效达50%?60%。国际上已鉴定出多种可诱导玉米获得系统抗性的木霉菌源激发子,其中包括S m1、纤维素酶、疏水蛋白和A vr4/Avr9等效应因子。本课题组近年鉴定出T hc6(锌指蛋白类转录因子)、P AF‐AH和T hph1/Thph2的编码产物在系统诱导以J A/ET信号调控的玉米抗弯孢菌叶斑病中具有重要作用,符合植物免疫M AMPs模式,为全面认识木霉菌诱导免疫机理提供了重要理论依据。木霉菌诱导玉米从根至叶片的防御反应系统传导机制还需深入研究。

Microbes in 10 genera, namely, Trichoderma, Gliocladium, Chaetomium, Bacillus, Burkhoderia, Streptomyces, Pseudomonas, Pantoea, Enterobacter, and Macrobactefium, have been tested or used for controlling corn diseases. To our knowledge, 14 bacterial, 17 fungal, and 1 actinomyces species have been widely used for developing biocontrol agents against corn diseases. More than 50 commercialized bio-pesticides and bio-fertilizers are produced from Trichoderma spp., among which T. harzianium strain T22-based products are successfully applied in biocontrol of corn diseases worldwide. In China, Trichoderma spp. has been used to develop four types of formulation： wettable powder, granules, water dispersible granules （WDG）, and seed dressing agent. Seven kinds of Trichoderma-based bio-fungicides have been registered, including 6 kinds of wettable powder and 1 kind of WDG. All registered Trichoderma-based biofungicides are used against seedling damping-off, root rot, grey mould, downy mildew in tomato, ornamental lilv and cucumber, and sheath blight in wheat. However, no Trichoderma-based fungicides have been registered for corn disease control. Eleven registered bio-fertilizers have been produced from Trichoderma spp., but only two of these bio-fertilizers are allowed to be applied on corn crops The Trichoderma-based granules and seed dressing agent developed in our laboratory have been proven highly effective in controlling corn stalk rot and sheath blight; the control efficacies of the granules ranged from 65% to 87% under field conditions. A Trichoderma-based wet-table powder was developed, and it was able to offer control of southern corn leaf blight by about 50% to 60%. A group of elicitors/effectors including Sml, cellulase, hydrophobin, and Avr4/Avr9 have been dentified, and they may be closely associated with the induction of induced systemic resistance （ISR） against corn diseases n addition, several genes （Thphl/Thph2, Thc6, and PAF-AH） in T. harzianum strain T28 have been identified to be devoted to corn ISR against the foliar disease Curvularia leaf spot; it is mainly governed by the JA/ET signaling pathway due to the nteraction of T28 and corn root. This finding was strongly supported by the microbe-associated molecular pattern model, which generally provides a new insight into Trichodermo-based induction of corn immunity. The long-distance transduction of corn defense response from root to leaf mediated by Trichoderma spp. would be a new focus of future studies.