甜瓜细菌性果斑病生防菌株BW-6的筛选和鉴定

Isolation and identification of bio-control bacterial strain BW-6 against bacterial fruit blotch of sweet melon

甜瓜细菌性果斑病是由西瓜嗜酸菌(Acidovorax citrulli Schaad et al.)引起的一种毁灭性病害。本研究以西瓜嗜酸菌为指示菌,采集97个土样,采用土壤稀释平板法和对峙培养进行拮抗菌的分离和筛选,获得19株细菌可以抑制西瓜嗜酸菌生长。通过离体叶片、盆栽试验进行生测,BW-6菌株对甜瓜果斑病的生防效果最好,且比较稳定,防效达80.3%。在甜瓜叶面进行室外定殖试验表明,BW-6菌株可以在甜瓜叶面上大量定殖,但随着时间的推移菌数逐渐减少。根据菌株BW-6的形态特征、生理生化特性以及16SrDNA序列分析综合考察,鉴定其为枯草芽胞杆菌(Bacillus subtilis Cohn)。

Bacterial fruit blotch of sweet melon, caused by Acidovorax citrulli, is a devastating bacterial disease. Nineteen strains with highly antagonistic activity were isolated from 97 soil samples using dilution plate and dual culture method. In this study, A. citrulli was an indicator. Strain BW-6 showed high and stable antagonistic effect both on detached leaves and pot experiment, and its control efficiency was 80.3%. Experiment on leaves of sweet melon indicated that strain BW-6 was able to colonize on leaves, but the quantity of bacteria tended to drop off o- ver time. Strain BW-6 was identified as Bacillus subtilis by its morphological, physiological and biochemical char- acteristics and 16S rDNA sequence analysis.