关键词: 胡萝卜软腐欧文氏菌, 解淀粉芽孢杆菌, 进化树, 群体动态, 系统诱导抗病性

Abstract:

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.

Key words: Erwinia carotovora subsp. carotovora, Bacillus amyloliquefaciens, phylogenetic tree, population dynamics;induced systemic resistance