南方红豆杉根腐病病原及其拮抗芽胞杆菌的鉴定

经形态学特征观察、致病性测定及rDNA-ITS序列分析,首次确定红豆杉根腐病病原为尖孢镰刀菌(Fusarium oxysporum)。采用平板对峙培养法从健康植株根际土壤中筛选得到3株对尖孢镰刀菌具有明显拮抗作用的芽胞杆菌YB6、YB15、YB37。经形态学、生理生化及16SrDNA同源性分析,并通过构建16SrDNA系统发育树,将YB6、YB15和YB37分别鉴定为蜡样芽胞杆菌(Bacillus cereus)、解淀粉芽胞杆菌(B.amyloliquefaciens)和多黏类芽胞杆菌(Paenibacillu polymyxa),其中多黏类芽胞杆菌拮抗效果最好,具有进一步研究开发的潜力。本研究通过对南方红豆杉根腐病病原鉴定及其拮抗芽胞杆菌的筛选,对该病的防治提供了理论依据。

Identification of the pathogen isolated from root rot of Taxus chinensis var. mairer and screening of its antagonistic Bacillus

In this study, the pathogen isolated from root rot of Taxus chinensis var. mairer was first indentified. Based on morphological characteristics, pathogenicity and rDNA ITS sequence analysis, the results showed that the pathogen of root rot disease of T. chinensis var. mairer was Fusarium oxysporum. The tablet confrontation training method was adopted to screen the antagonistic Bacillus species from the healthy plant rhizosphere, and three strains with obvious antagonistic effect were obtained, namely YB6, YB15 and YB37. Through morphological, physiological, biochemical and 16S rDNA homology analysis as well as the construction of 16S rDNA phyloge netic tree, we found that YB6, YB15 and YB37 were Bacillus cereus, B.amyloliquefaciens and Paenibacillus polymyxa, respectively. The antagonistic effect of P. polymyxa was the best with further research and development potential. This study provides some valuable information for effective prevention and treatment of this disease.