为明确野尻链霉菌Streptomyces nojiriensis 9-13对大豆炭疽病病原菌的抑制活性及作用机制,采用对峙培养法、菌丝生长速率法和孢子萌发法分别测定该菌株对引起大豆炭疽病的平头炭疽菌 Colletotrichum truncatum、胶孢炭疽菌 C gloeosporioides 和 C plurivorum,以及对苯醚甲环唑和啶氧菌酯的平头炭疽菌抗药性突变体的拮抗活性、抑菌活性和对分生孢子萌发的抑制活性;观察野尻链霉菌9-13发酵液对平头炭疽菌菌丝形态和细胞结构的影响.结果表明:野尻链霉菌9-13对引起大豆炭疽病的3种病原菌平头炭疽菌、胶孢炭疽菌和C.plurivorum均具有较强的拮抗作用.野尻链霉菌9-13的10％发酵液对3种大豆炭疽菌菌丝生长的抑制率为56.67％～87.04％,且抑制活性与发酵液的浓度呈正相关.此外,野尻链霉菌9-13对苯醚甲环唑和啶氧菌酯的平头炭疽菌抗药性突变体同样具有较强的拮抗作用.野尻链霉菌9-13的10％发酵液对苯醚甲环唑和啶氧菌酯的平头炭疽菌抗药性突变体的菌丝生长抑制率分别为74.79％～77.80％和46.53％～58.33％.野尻链霉菌9-13的10％发酵液对9种供试炭疽菌分生孢子萌发的抑制率均达100.00％o野尻链霉菌9-13发酵液可以破坏平头炭疽菌菌丝的细胞膜结构,使细胞发生质壁分离.发酵液处理后平头炭疽菌菌丝表现出膜相关的红色荧光斑点.表明野尻链霉菌9-13是一株具有开发前景的生防菌株.
Abstract
In order to uncover the antifungal activity and action mechanism of Streptomyces nojiriensis 9-13 against soybean anthracnose caused by Colletotrichum species,antifungal effects against different Colletotrichum spp.,including C.truncatum,C.gloeosporioides,C.plurivorum,difenoconazole-resistant mutants and picoxystrobin-resistant mutants of C.truncatum,were assessed using the method of dual culture and the suppression of mycelial growth and conidial germination.In addition,the effects of S.nojiriensis 9-13 on the mycelial morphology and cellular structure of C.truncatum were studied with scanning electron microscopy,transmission electron microscopy and fluorescence confocal micros-copy.The results showed that the strain 9-13 presented significant antagonistic activity against three pathogens associated with soybean anthracnose,e.g.C.truncatum,C.gloeosporioides,and C.plurivo-rum.The inhibition rate of 10％fermentation filtrate of the strain 9-13 against the above three Colletotri-chum species ranged from 56.67％-87.04％and increased in a dose-dependent manner.Additionally,the strain 9-13 also exhibited strong antagonistic activity against difenoconazole-resistant mutants and pi-coxystrobin-resistant mutants of C.truncatum.The inhibition rate of 10％fermentation filtrate of the strain 9-13 against difenoconazole-resistant mutants and picoxystrobin-resistant mutants was 74.79％-77.80％and 46.53％-58.33％,respectively.And 10％fermentation filtrate of the strain 9-13 could com-pletely inhibit spore germination of all tested pathogens.Scanning and transmission electron microsco-py revealed that strain 9-13 fermentation could induce severe mycelial deformation,disrupt cell mem-brane integrity and cause cell plasmolysis.In addition,hyphae treated with strain 9-13 fermentation ex-hibited membrane-associated red fluorescence puncta upon staining with FM4-64 compared with the control group.These results indicate that S.nojiriensis 9-13 is a promising biocontrol agent.
维普
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