ABSTRACT

Fusarium oxysporum f. sp. cucumerinum (FOC) is one of the most destructive pathogens in many cucumber-growing countries around the globe. There is still lack of high-resistant cucumber cultivars against this pathogen, and the use of fungicides is threatening the environmental conditions. However, biocontrol is an environment-friendly technique in plant protection. In this regard, the present work was aimed to screen antagonistic bacterial strains from vermicompost to against FOC in cucumber. Using the dilution-plate method, 374 bacterial strains were isolated from fresh vermicompost. A total of 28 bacterial strains showed antagonistic activity against FOC, among which strain D2 exhibited the best inhibitory effect on the growth of FOC, with the diameter of the growth inhibition zone of 28.28 mm. Then strain D2 was classified and identified based on the morphology and colony characteristics, physiological and biochemical characteristics, and 16S ribosomal DNA (rDNA) sequence homology. For molecular identification, a 1,462-bp fragment of 16S rDNA of strain D2 was obtained. Based on its morphological, physiological, and biochemical characteristics, strain D2 was identified as Burkholderia cenocepacia.

摘要

尖孢镰刀菌f。sp。黄瓜（FOC）是全球许多黄瓜种植国家中最具破坏性的病原体之一。仍然缺乏针对这种病原体的高抗性黄瓜品种，杀真菌剂的使用正在威胁环境条件。但是，生物防治是植物保护中的一种环境友好技术。在这方面，本发明的目的是筛选黄瓜中从ver虫到抗FOC的拮抗细菌菌株。使用稀释板法，从新鲜的ver堆中分离出374个细菌菌株。共有28株对FOC有拮抗作用，其中D2株对FOC的生长表现出最好的抑制作用，其生长抑制区的直径为28.28 mm。然后根据形态和菌落特征，生理生化特征以及16S核糖体DNA（rDNA）序列同源性对D2菌株进行分类和鉴定。为了进行分子鉴定，获得了菌株D2的16S rDNA的1,462-bp片段。根据其形态，生理和生化特性，将菌株D2鉴定为伯克霍尔德氏菌。