人参内生细菌NJ13在宿主体内定殖特性及对人参黑斑病的防治效果

Colonization characteristics of endophytic bacteria NJ13 in Panax ginseng and its biocontrol efficiency against Alternaria leaf spot of ginseng

为明确人参内生生防细菌NJ13在宿主体内的定殖特性,该研究通过抗生素诱导获得了同时对利福平和硫酸链霉素具有稳定抗性的双抗标记菌株NJ13-R,分析了菌株在宿主体内的定殖特性,并研究了NJ13对人参黑斑病的田间防治效果。结果表明,菌株在人参根、茎、叶部均可定殖,而且定殖量与接种浓度呈正相关。菌株可在人参不同部位侵染植株并在体内进行转移,在根部和叶部定殖量表现为先升后降的变化趋势,而在茎部呈先升高后平缓趋势。研究还发现,生防细菌NJ13表现出对宿主特定部位具有一定的偏好性,随着时间推移在茎部的定殖量高于其他部位。田间试验证明,生防细菌NJ13对人参黑斑病具有较好的防治作用,其中0.76×108cfu·mL-1发酵液防效达75.62%,高于对照药剂0.67 mg·L-150%嘧菌环胺WG的防效(73.06%)。

To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng,this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic.The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria leaf spot of ginseng in the field were studied.The results showed that the strain could colonize in root,stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration.Meanwhile,the strain could infect and then transfer in different tissues of ginseng.The colonization amount of strain in roots and leaves of ginseng increased first and then decreased.However,the tendency of colonization amount of strain in stems was ascend at first and then descend slowly,and was more than that in roots and leaves along with time,which had a preference to specific tissue of its host.In field experiment,the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng.The biocontrol efficiency of fermentation broth at the concentration of0.76 × 108cfu·mL- 1reached 75.62%,which was close to the controlling level（73.06%） of 0.67 mg·L- 150% cyprodinil WG.