【作者】 王万能；

【导师】 肖崇刚；

【作者基本信息】 西南农业大学 ， 植物病理学， 2003， 硕士

【摘要】 烟草黑胫病是烟草上重要的毁灭性病害，从苗期到成株期都可发生，生产上主要以化学防治为主，不仅药剂难以长期持续有效，还严重污染环境和危害人体健康。利用有益微生物防治植物病害，持续有效，保护环境，是近年来研究的热点。已经报道的烟草黑胫病的生物防治主要是利用从根围分离的真菌、细菌，但由于定殖差，受环境条件制约，防效难以稳定。植物内生细菌分布于植株体内，生长繁殖相对稳定，是很好的生防菌资源。本研究论文就防治烟草黑胫病的内生细菌进行了筛选，并对其作用机理进行了初步研究。 1、本论文对烟草疫霉培养产孢方法进行了研究。通过实验，芝麻培养基、黑麦培养基、燕麦培养基可用来培养烟草疫霉，烟草疫霉在三种培养基上的平均每天生长量为1.10cm、0.78cm、0.86cm。芝麻培养基、黑麦培养基为烟草疫霉产孢子囊较好的培养基，产孢能力强，分别为2.52×10~4个孢子囊／cm~2、2.07×10~4个孢子囊／cm~2。而且孢子囊释放率高，分别为40.0％、32.1％。 2、通过分离内生细菌、平板筛选，共获得238个内生细菌菌株，对烟草疫霉有抑制作用的菌株有13个，占5.5％，都来自根茎部。通过盆栽试验，获得了对烟草黑胫病有很好防效的内生细菌118、57、93等菌株，在温室控病实验中它们的防效可达69.23％、61.53％、65.38％。为以后大田试验以及生产应用打下了一定的基础。 3、论文对内生细菌118菌株防治烟草黑胫病的机理进行了初步研究，其作用机理包括直接拮抗作用和诱导抗病作用。118菌株的发酵液虽不能抑制烟草疫霉游动孢子囊释放，但能抑制菌丝生长、游动孢子游动及萌发；而且118菌株还能诱导烟草体内POD、PPO、PAL等抗病相关酶的活性明显升高。研究其生防作用机理为以后在其他作物上开发利用内生细菌提供了一定的理论依据。更多还原

【Abstract】 Tobacco Black Shank is one of the important ruinous diseases of tobacco. Chemical control is mainly adopted in production ,but tobacco is susceptible to Phytophthora parasitica var. nicotianae in the all growing time. Pesticide is difficult to control it continuously, and it also contaminates environment and harms men. Biocontrol is sustained effective and protects environment. Biocontrols of Tobacco Black Shankthat have been reported mainly isolated and utilized fungi , bacteria fromsurroundings of tobacco roots, their control effects are not steady for their poor abilities of colonization . Endophytic bacteria can exit in plant well, and control diseases stably. Endophytic bacteria are good biocontrol bacteria. In the thesis, I screened the Endophytic bacteria that can control Tobacco Black Shank and research on the mechanisms’of strain 118.1. Some ways of culturing hypha and producing zoosporangia were studied in this thesis. Through experiment, sesame agar, rye agar and oat ag&r can be used to culture Phytophthora parasitica var. nicotianae which grew well on them, their growth speeds were 1. 10cm, 0. 78cm, 0. 86cm per day. Sesame agar, rye agar can be used to culture Phytophthora parasitica var. nicotianae to produce zoosporangia, their outputs of zoosporangia were2.52×104 zoosporangia/cm2, 2.07×104 zoosporangia /cm2, their discharging rates were 40. 0% and 32. 1%.2. Through isolating endophytic bacteria and screening on plate, 238 endophytic bacteria strains were gained altogether. There were 13 strains that can restrain Phytophthora parasitica var. nicotianae growing on plates among them. They were isolated from roots and stems of tobacco. In greenhouse trail, endophytic bacteria 118,57,93 can control Tobacco Black Shank well, their control effects were high to 69. 23%, 61. 53%, 65. 38% , they can be used in production in advance.3. Through researching on the mechanisms of strain 118, its mechanisms include direct inhibition and induced disease resistance. Although the ferment liquid of strain 118 can not restrain zoosporangia discharging , but it can inhibit the hypha growing , zoospores moving about and germinating which are important links of Tobacco Black Shank developing , If any link is cut off , the disease could not develop. The strain 118 can induce activities of POD, PPO, PAL of tobacco increase, which are the plant defense enzymes. The research on the mechanisms of strain 118 can provide scientific basis for developing and utilizing endophytic bacteria on other plants.更多还原