本文選題：拮抗菌 + 篩選��； 參考：《內(nèi)蒙古師范大學(xué)》2017年碩士論文

【摘要】：黃瓜是一種世界性蔬菜作物,黃瓜枯萎病作為一種土傳病害,是世界各國黃瓜生產(chǎn)中的主要病害之一,由尖孢鐮刀菌(Fusarium oxysporum)引發(fā)。長期以來,化學(xué)農(nóng)藥在黃瓜枯萎病的防治方面發(fā)揮了重要作用,但過度使用化學(xué)農(nóng)藥,容易使病菌產(chǎn)生抗藥性、降低黃瓜品質(zhì)、污染環(huán)境、影響人體健康。因此采用高效、安全、環(huán)境友好型生物防治成為最佳選擇。本研究通過平板對(duì)峙實(shí)驗(yàn),從分離自青海湖周邊土壤的菌株中篩選出對(duì)黃瓜枯萎病原菌具有良好的抑制作用的拮抗細(xì)菌246-1和拮抗放線菌11F,其中拮抗細(xì)菌246-1對(duì)黃瓜枯萎病原菌的抑菌率為60%;而拮抗放線菌對(duì)黃瓜枯萎病原菌的抑菌率為68.6%,并發(fā)現(xiàn)這兩株拮抗菌對(duì)其他病原菌也有不同程度的拮抗作用,顯示了其具有抑菌廣譜性。通過對(duì)拮抗菌株進(jìn)行表型鑒定、生理生化鑒定和分子生物學(xué)鑒定,確定拮抗菌株246-1為多粘類芽孢桿菌(Paenibacillus polymyxa),而拮抗放線菌11F為黃赭色鏈霉菌(Streptomyces silaceus)。采用抑菌圈實(shí)驗(yàn)篩選出最適合多粘類芽孢桿菌246-1產(chǎn)拮抗物質(zhì)的培養(yǎng)基,用單因素實(shí)驗(yàn)方法對(duì)其培養(yǎng)條件進(jìn)行優(yōu)化。結(jié)果表明,246-1菌株的培養(yǎng)基配方為可溶性淀粉17.5 g·L-1,酵母浸出粉4 g·L-1,蛋白胨25g·L-1,Na Cl 1.25 g·L-1,Na2HPO4 0.5 g·L-1,Ca Cl2 1g·L-1,蔗糖15 g·L-1,最佳培養(yǎng)時(shí)間48 h,初始p H 7.0,培養(yǎng)溫度30℃。通過篩選fusaricidins提取純化和檢測方法,確定發(fā)酵液酸化是fusaricidins提取純化的一個(gè)重要步驟,同時(shí)確定乙腈/水/TFA檢測體系為fusaricidins HPLC檢測流動(dòng)相。并進(jìn)一步分析了多粘類芽孢桿菌246-1對(duì)黃瓜幼苗的促生作用,在黃瓜幼苗根際土壤中的定殖能力和對(duì)黃瓜枯萎病的防效作用。盆栽試驗(yàn)結(jié)果表明,菌株246-1的發(fā)酵液對(duì)黃瓜枯萎病菌表現(xiàn)出很強(qiáng)的抑制作用,同時(shí)該菌株在黃瓜幼苗根際具有很好的定殖能力,表現(xiàn)了對(duì)黃瓜幼苗的顯著促生效果。這些生防效應(yīng)的研究為研制微生物可濕性粉劑和有生物有機(jī)肥提供了基礎(chǔ)依據(jù)。
[Abstract]:Cucumber wilt is a worldwide vegetable crop. As a soil-borne disease, cucumber wilt is one of the major diseases in cucumber production in the world, which is caused by Fusarium oxysporum (Fusarium oxysporum). For a long time, chemical pesticides have played an important role in the control of cucumber wilt. However, excessive use of chemical pesticides can easily lead to drug resistance, reduce cucumber quality, pollute the environment and affect human health. Therefore, it is the best choice to adopt high efficiency, safety and environment-friendly biological control. In this study, plate confrontation experiments were carried out, The antagonistic bacteria 246-1 and 11F were screened from the soil around Qinghai Lake to inhibit the pathogen of cucumber wilt, and the inhibitory rate of the antagonistic bacteria 246-1 to the pathogen of cucumber wilt was 60%. The inhibition rate of antagonistic actinomycetes against cucumber wilt pathogen was 68.6, and it was found that these two antagonistic bacteria also had antagonistic effects on other pathogens. It is shown that it has broad spectrum of bacteriostasis. By phenotypic identification, physiological and biochemical identification and molecular biological identification, the antagonistic strain 246-1 was identified as Paenibacillus polymyxa1, and the antagonistic actinomycetes 11F was Streptomyces silaceusus. The best medium for producing antagonist substance of Bacillus polymyxis 246-1 was screened by inhibition circle experiment, and the culture conditions were optimized by single factor experiment. The results showed that the culture medium was soluble starch 17.5 g L -1, yeast extract 4 g L -1, peptone 25 g L -1 NaCl 1.25 g L -1 Na 2HPO 4 0.5 g L -1 Ca Cl 2 1g L -1, sucrose 15 g L -1, the optimum culture time 48 h, initial pH 7.0, culture temperature 30 鈩，

本文編號(hào)：2004869