芋头软腐病拮抗菌的筛选及生防效果研究

分别从蔬菜田土壤和采后芋头表面黏附土壤中分离纯化到267和244 株菌株，通过平板拮抗实验，发现其中6 个菌株对胡萝卜软腐欧文氏菌（Erwinia carotovora subsp. carotovora，Ecc）产生了清晰且明显的拮抗圈（直径＞10 mm）。利用芋头对它们的生物防控效果进行复筛，结果发现BGP14菌株发酵液处理芋头的发病率仅为6.7%，显著低于其他5 个菌株（P＜0.05）。根据BGP14的形态学特征、芽孢产生及16S rRNA和gyrB基因的部分核酸序列，该菌株被鉴定为解淀粉芽孢杆菌BGP14（Bacillus amyloliquefaciens）。BGP14在芋头伤口上具有较强的定殖能力，并将病原菌Ecc的群体数量压制在一个较低水平。BGP14与病原菌Ecc联合处理芋头的苯丙氨酸解氨酶（phenylalanine ammonia-lyase，PAL）活性显著高于其他处理。以上结果表明，解淀粉芽孢杆菌BGP14对病原菌E. carotovora具有强大的拮抗活性，能够有效防治贮藏期芋头软腐病，具有潜在的应用开发前景。

Screening of Antagonistic Strain and Its Biocontrol Ability against Postharvest Soft Rot of Taro Caused by Erwinia carotovora subsp. carotovora

In this study, 267 and 244 strains were isolated from the vegetable farm soil and the adherent soil on postharvesttaros, respectively. Six strains generated clear and obvious antagonistic zones (diameter ＞ 10 mm) on 2YT agar plates withErwinia carotovora subsp. carotovora (Ecc). in vivo assays showed that the BGP14 cell culture was the most effective incontrolling the postharvest soft rot of taros among six antagonistic strains tested. The incidence of soft rot in taros treatedby the BGP14 cell culture was only 6.7%, which was significantly lower than that of those treated by five other strains(P ＜ 0.05). Based on morphology, sporulation, and partial nucleotide sequences of 16S rRNA and gyrB gene, the isolateBGP14 was identified as Bacillus amyloliquefaciens. The antagonist BGP14 had a stronger colonizing ability in tarowoundas compared to the pathogen Ecc in the process of biological control, and the viable count of Ecc was suppressedto a very low level. In addition, the treatment with both BGP14 and Ecc induced a higher activity of phenylalanineammonia-lyase (PAL) than with others in taros. In conclusion, the present study demonstrated that the isolate BGP14showed highly antagonistic activity against Ecc, and could effectively control the postharvest soft rot of taros, thuspossessing potential application prospect.