致病杆菌Xenorhabdus bovienii SN84次生代谢产物对三种植物病原真菌抑菌作用的研究

发布时间：2018-04-18 21:38

  本文选题：生物农药 + 致病杆菌Xenorhabdus　； 参考：《沈阳农业大学》2017年硕士论文

【摘要】：随着人类社会的不断发展,人们对生活质量、生存环境的要求也不断提高,虽然人类的种种要求推动了科学技术的发展,但也随之带来很多环境问题。在农业生产中,化学农药是最主要也是最为有效防治病虫害的方式,由于环境的不断恶化以及人们环保意识的不断提高,寻找代替化学农药的替代品已成为热点。生物农药因其低残留、低毒、不易产生抗药性、选择性强等优点已成为世界各国的研究重点。农用抗生素主要指生物农药中的微生物源农药,目前在杀虫和杀菌方面已取得显著的防治效果,成为当今研究的热点。本试验从土壤中分离得到一株昆虫病原线虫共生菌Xenorhabdus bovienii SN84,研究发现该菌株的次生代谢产物可有效抑制番茄灰霉菌、辣椒疫霉菌和大豆疫霉菌的生长。通过试验测定了致病杆菌Xenorhabdus bovienii SN84发酵液、粗提物以及分离得到的7种纯化合物对番茄灰霉菌、辣椒疫霉菌和大豆疫霉菌三种植物病原真菌的抑制效果,并利用致病杆菌Xenorhabdus bovienii SN84的发酵液对番茄幼苗进行生物测定,以期得到一株能够抑制植物病原真菌的新型农用抗生素或其前导活性产物的菌株,为解决生产中缺少对三种靶标菌株具有安全高效的农用抗生素品种提供可能。主要研究结果如下:测定致病杆菌Xenorhabdus bovienii SN84菌株发酵液对三种植物病原真菌的抑菌效果,结果显示,Xenorhabdusbovienii SN84菌株无菌发酵液对三种靶标病原真菌均有显著的抑制效果。当Xenorhabdusbovienii SN84无菌发酵液的浓度达到2%时,对番茄灰霉病菌菌丝生长的抑制可达到近50%;当Xenorhabdus bovienii SN84无菌发酵液的浓度达到0.6%时,对辣椒疫霉病菌和大豆疫霉病病原菌菌丝生长的抑制可达到近50%。测定致病杆菌Xenorhabdus bovienii SN84菌株发酵粗提物对三种植物病原真菌的抑菌效果,结果显示,得到A、B、C和D四个组分中仅B组分有抑菌效果,且对番茄灰霉菌的抑制效果最佳,对另外两种植物病原真菌的抑制效果不佳,固将番茄灰霉菌作为下一步试验研究重点,并探究抑菌效果较发酵液有所降低的原因。测定从致病杆菌Xenorhabdus bovienii SN84菌株发酵产物中分离得到的7种纯化合物对番茄灰霉菌孢子萌发的抑制作用,结果显示仅C2-2对番茄灰霉病病菌孢子萌发的抑制作用最强,且持续作用时间最为持久,若其进行更加深入研究,有望得到一株对番茄灰霉病病菌抑制活性较强的生物农药或其先导化合物。测定致病杆菌Xenorhabdus bovienii SN84菌株发酵液对番茄灰霉病的抑制作用,进而检测该菌株发酵液对番茄幼苗的保护作用。结果显示,随着加入无菌发酵液的量的增多,灰霉病的发病率逐渐降低。当Xenorhabdus bovienii SN84无菌发酵液的浓度为8%时,对番茄幼苗起到有效的预防番茄灰霉病的效果。表明了进一步研究致病杆菌Xenorhabdus bovienii SN84菌株作为生物农药或其先导化合物的重要意义。
[Abstract]:With the continuous development of human society, the quality of life, living environment requirements are also constantly raised, although human requirements promote the development of science and technology, but also bring a lot of environmental problems.In agricultural production, chemical pesticide is the most important and most effective way to control diseases and insect pests. Due to the deterioration of the environment and the improvement of people's awareness of environmental protection, finding a substitute for chemical pesticides has become a hot spot.Because of its advantages of low residue, low toxicity, low resistance and high selectivity, biological pesticides have become the focus of research all over the world.Agricultural antibiotics mainly refer to microbial pesticides in biological pesticides. At present, significant control effect has been achieved in insecticidal and bactericidal aspects, and has become a hot research topic.A symbiotic bacterium Xenorhabdus bovienii SN84 was isolated from soil. It was found that the secondary metabolites of this strain could effectively inhibit the growth of Tomato Ash, Phytophthora capsici and Phytophthora sojae.The inhibitory effects of Xenorhabdus bovienii SN84 fermentation broth, crude extract and seven compounds isolated from pathogenic bacillus Xenorhabdus bovienii SN84 on three plant pathogenic fungi, Tomato ash fungus, Phytophthora capsici and Phytophthora sojae, were studied.The fermentation broth of Xenorhabdus bovienii SN84 was used for bioassay of tomato seedlings in order to obtain a new agricultural antibiotic or its leading active product which could inhibit plant pathogenic fungi.It is possible to solve the problem of the lack of agricultural antibiotic varieties with safety and efficiency for three target strains in production.The main results were as follows: the bacteriostasis effect of the fermentation broth of Xenorhabdus bovienii SN84 on three plant pathogenic fungi was determined. The results showed that the aseptic fermentation broth of Xenorhabdusbovienii SN84 had significant inhibitory effect on all three target pathogenic fungi.When the concentration of Xenorhabdusbovienii SN84 aseptic fermentation broth reached 2%, the inhibition of mycelium growth of Botrytis cinerea was nearly 50%, and when the concentration of Xenorhabdus bovienii SN84 aseptic broth reached 0.6%,The hyphal growth of Phytophthora capsici and Phytophthora sojae was inhibited nearly 50%.The antimicrobial effects of the crude extracts of pathogenic bacillus Xenorhabdus bovienii SN84 on three plant pathogenic fungi were determined. The results showed that only B and D of the four components of Xenorhabdus bovienii SN84 had bacteriostasis effect, and the inhibitory effect was the best to the ash fungus of tomato.The inhibition effect of the other two plant pathogenic fungi was not good. The tomato ash fungus was regarded as the key point of the next experiment, and the reason why the bacteriostatic effect was lower than the fermentation broth was explored.The inhibitory effects of seven pure compounds isolated from the fermentation products of pathogenic bacillus Xenorhabdus bovienii SN84 on the spore germination of Tomato Aspergillus cinerea were determined. The results showed that only C2-2 had the strongest inhibitory effect on the spore germination of Botrytis cinerea.If it is studied more deeply, it is hopeful to obtain a biological pesticide or its leading compound which has strong inhibitory activity against Botrytis cinerea.The inhibitory effect of fermentation broth of pathogenic bacillus Xenorhabdus bovienii SN84 on Botrytis cinerea was determined, and then the protective effect of the fermentation liquid on tomato seedlings was tested.The results showed that the incidence of gray mold decreased with the increase of aseptic fermentation broth.When the concentration of Xenorhabdus bovienii SN84 aseptic fermentation broth was 8, it had an effective effect on preventing tomato gray mold.The results indicate that it is important to further study the pathogenic bacillus Xenorhabdus bovienii SN84 as a biological pesticide or its leading compound.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S476
，

本文编号：1770198