邹朔飞 董祥立 李继业 丁海霞 李治模

摘 要：筛选用于防治烟草黑胫病的拮抗链霉菌，并可作为化学药剂补充或替代品。采用稀释平板法分离土壤链霉菌，采用平板对峙法筛选拮抗链霉菌，通过形态观察、生理生化试验及16S rRNA序列分析鉴定目标菌株，通过田间小区试验评价目标菌株的生防潜力和对烤烟的促生效果。从贵州省湄潭县采集烤烟根际土壤，分离到放线菌73株。从中筛选获得1株对烟草黑胫病菌拮抗效果良好的菌株MT35，该菌鉴定为郝氏链霉菌（Streptomyces halstedii）。结果表明，施用MT35后烟株茎围、茎高和叶宽均有增加，对烟草黑胫病的防效良好，相对防效为 75.3%。筛选到1株对烟草黑胫病菌有强拮抗作用的郝氏链霉菌（S. halstedii）MT35，该菌对烟草黑胫病具有良好的田间防效且对烟株具有促生效果。

关键词：烟草黑胫病;生物防治;链霉菌

中图分类号：Q935

文献标识码：A

文章编号：1008-0457（2021）02-0049-05

国际DOI编码：10.15958/j.cnki.sdnyswxb.2021.02.008

Abstract：Tobacco black shank is one of the most serious diseases of tobacco in Guizhou，China. An antagonistic Streptomyces strain against Phytophthora nicotianawas isolated from soils，which could be used as a supplement or substitute for chemical agents.Antagonistic strain were isolated by the dilution plate method and thedual-culture test. The target strains were identified based on morphology，physiological and biochemical experiments and 16S rRNA sequence analysis. The biocontrol potential and growth-promotion effect of the target strain were evaluated by fieldtrials.The results showed that 73 strainsofStreptomyceswere isolated from the soil samples of healthy tobacco rhizosphere in Meitan County，Guizhou province.OneStreptomyces strainnamed MT35 with obvious antagonism effect on tobacco black shankwas obtained from the screening，and which was identified as Streptomyces halstedii. The results of field experiments showed that MT35existedobvious control effects on tobacco black shank，witha relativecontrol effect of 75.3%.The stem circumference，stem height and leaf width oftobacco were increased significantly afterapplying MT35.Streptomyces halstediiMT35 with distinctively antagonismtoPhytophthora nicotianawas isolated and characterized，which hadwell biocontrol effect and growth-promoting effecton tobacco plants in field trail.

Keywords：Tobacco black shank;biocontrol;Streptomyces

烟草黑胫病是由烟草疫霉（Phytophthora nicotiana）引起的毁灭性病害[1]，该病在全世界40余个国家和地区都有发生，分布非常廣泛[2]。烟草黑胫病在我国各个烟区均有发生，贵州省是我国烟草的主要栽培地之一，长期种植烤烟导致该病发病率逐年上升，严重影响烟叶品质和农民收入[3]。目前生产上主要使用化学药剂防治且有较好的效果，但化学药剂的使用伴随着严峻的“3R”问题，病原菌的抗药性逐年增加，田间用药量逐年上升，因此对环境友好的生物防治已成为研究热点[4-5]。使用放线菌，尤其是链霉菌（Streptomyces），防治植物病害一直是国内外生物防治研究的热门领域。……