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【6h】 Mechanisms of biological control of Fusarium root and stem rot of greenhouse cucumber by Gliocladium catenulatum.

机译链状胶质生物防治大棚黄瓜镰刀菌根腐病的机理。

【摘要】Gliocladium catenulatum strain J1446 (formulated as Prestop WP, Verdera Oy) is a biological control agent of Fusarium root and stem rot caused by Fusarium oxysporum f. sp. radicis-cucumerinum on greenhouse cucumber plants. The mechanisms involved in biocontrol efficacy are currently unknown. Following transformation of G. catenulatum with the beta-glucuronidase (uidA) gene, blue-stained mycelia could be seen growing on the surface and within epidermal and cortical cells of roots, stems and shoots 3 weeks after treatment. Application of G. catenulatum preceding inoculation with Fusarium significantly reduced pathogen populations on roots compared to plants inoculated with Fusarium alone, while densities of the biocontrol agent increased in the presence of the pathogen. Factors influencing root population levels included nutrient solution pH, temperature and growing media type, while cucumber cultivar, root wounding and addition of nutrients did not appear to significantly affect colonization. In culture, G. catenulatum produced chitinase and beta-1,3-glucanase enzymes on chitin or laminarin as a sole carbon source, respectively, and caused localized degradation of Fusarium hyphae. Cucumber root extracts from G. catenulatum-colonized plants had significantly higher levels of glucanase at 7 days postapplication compared to untreated controls. Reverse-transcription polymerase chain reaction using primers designed to amplify a beta-1,3-glucanase gene confirmed G. catenulatum glucanase expression on roots. In a split-root system, G. catenulatum applied to one-half of the roots prior to inoculation with Fusarium on the other half did not significantly reduce disease compared to plants treated with Fusarium only. There was no detectable increase in chitinase, peroxidase or polyphenol oxidase enzyme activity in roots and leaves following treatment with G. catenulatum. Competitive colonization of the rhizosphere by G. catenulatum, which is facilitated by its mycoparasitic ability, are the primary mechanisms by which pathogen development and disease incidence is reduced.

【摘要机译】悬链神经胶质菌菌株J1446(被配制为Prestop WP,Verdera Oy)是由尖孢镰刀菌f引起的镰刀菌根和茎腐的生物防治剂。 sp。温室黄瓜植株上的黄瓜。目前尚不清楚涉及生物防治功效的机制。用β-葡糖醛酸糖苷酶(uidA)基因转化链霉菌后,在处理3周后,可以看到蓝染的菌丝生长在根,茎和芽的表面和表皮和皮质细胞内。与单独接种镰刀菌的植物相比,在接种镰刀菌之前施用链状假单胞菌显着减少了根上的病原体种群,而在病原体存在下生物防治剂的密度增加了。影响根种群水平的因素包括营养液的pH值,温度和生长介质的类型,而黄瓜品种,根伤和营养添加似乎并未显着影响定植。在培养中,链霉菌在几丁质或层粘连蛋白上作为唯一碳源分别产生几丁质酶和β-1,3-葡聚糖酶,并引起镰刀菌丝菌的局部降解。与未处理的对照相比,来自链状芽孢杆菌定植的植物的黄瓜根提取物在施用后7天具有显着更高的葡聚糖酶水平。使用设计用于扩增β-1,3-葡聚糖酶基因的引物进行逆转录聚合酶链反应,可确定根部链霉菌葡聚糖酶在根部的表达。在分根系统中,与仅用镰刀菌处理的植物相比,在另一半上接种镰刀菌之前,在一半的根上施用链状G. catenulatum不会显着减轻病害。用悬链线虫处理后,根和叶中的几丁质酶,过氧化物酶或多酚氧化酶的活性没有可检测到的增加。链霉菌的真菌寄生能力促进了其在根际的竞争性定殖,是减少病原体发育和疾病发生率的主要机制。

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