Selection of Trichoderma spp. strains for the control of Sclerotinia sclerotiorum in soybean

Abstract: The objective of this work was to evaluate, in vitro and in vivo, the potential of Trichoderma spp. strains to control Sclerotinia sclerotiorum in soybeans (Glycine max) and to perform the molecular identification of the best perfoming strains. The effect of 120 strains of Trichoderma spp. on the viability of S. sclerotiorum sclerotia was evaluated in vitro through immersion in suspension of conidia from the antagonists and plating in culture medium. The best performing strains were evaluated in vivo, in a greenhouse, for control of the pathogen inoculated on 'Pintado' soybean seeds and plants. Of the 120 strains tested in vitro, 22 strains of Trichoderma spp. caused 100% inhibition of sclerotia germination. In the greenhouse, five strains inhibited the negative effect of the pathogen on seed germination and two strains increased in up to 67% plant dry matter. The best performing strains were identified as T. koningiopsis (3 strains), T. asperelloides (3), T. atroviride (2), and T. virens (1). Trichoderma strains are able to protect soybean plants from the harmful effect of S. sclerotiorum and, at the same time, they can promote the growth of the aerial part in greenhouse conditions.

摘要：本研究旨在通过体外与体内实验，评估木霉菌属（Trichoderma spp.）菌株对大豆（Glycine max）核盘菌（Sclerotinia sclerotiorum）的生防潜力，并对表现最优的菌株开展分子鉴定。本研究采用将核盘菌菌核浸没于拮抗木霉菌分生孢子悬浮液后接种于培养基平板的方式，体外评估了120株木霉菌属菌株对核盘菌菌核活力的影响。针对体外实验中筛选出的最优菌株，本研究进一步在温室环境下开展体内生防实验，评估其对接种于‘Pintado’大豆种子及植株的病原菌的防治效果。在120株体外测试的木霉菌属菌株中，共有22株可完全抑制核盘菌菌核的萌发。温室实验结果显示，5株菌株可缓解病原菌对种子萌发的负面影响，另有2株菌株可使植株干物质积累量最高提升67%。经分子鉴定，表现最优的菌株分别为3株康宁木霉（T. koningiopsis）、3株拟康氏木霉（T. asperelloides）、2株深绿木霉（T. atroviride）以及1株绿木霉（T. virens）。木霉菌属菌株既可在温室条件下保护大豆植株免受核盘菌的危害，同时还可促进植株地上部分的生长。