本文選題：鏈霉菌702　切入點：農抗702　出處：《江西農業(yè)大學》2013年博士論文

【摘要】：鏈霉菌702是江西農業(yè)大學應用微生物實驗室從土壤中分離篩選到的具有獨立知識產權的一株鏈霉菌,其所產抗真菌組分農抗702經結構鑒定為多烯大環(huán)內酯類新結構化合物。本論文主要以水稻紋枯病菌為供試病原菌,從細胞、亞細胞、生理生化、分子生物學等方面研究了農抗702的抑菌機理及防病促生機制,主要研究結果如下：農抗702為淡黃色粉末狀物質,熔點170-173.5℃,旋光度為[α]D23.7=+4.3425.(c =1.09 in MeOH),紫外光譜表明在318 nm,303 nm,290nm處有三個典型吸收峰,符合多烯類抗生素圖譜特征；紅外光譜表明其含有C=O、C=C、C-O、OH和CH2。農抗702對熱較穩(wěn)定,溫度超過60℃活性開始下降；在強酸強堿條件下活性不穩(wěn)定,pH 5-6時活性穩(wěn)定。研究農抗702對病菌菌絲生長、菌核形成和萌發(fā)、孢子萌發(fā)的抑制作用,借助電鏡觀察其對菌絲超顯微形態(tài)和結構的影響。結果表明,農抗702對病菌菌絲生長抑制作用明顯,處理菌絲干癟和皺縮,細胞膜輪廓不清、破損,細胞器嚴重損傷,空泡化。農抗702明顯抑制病菌菌核的形成、萌發(fā)和孢子的萌發(fā)。通過農抗702作用后的水稻紋枯病菌相對電導率增加72.2%,蛋白質、核酸、Mg2+、K+離子等胞內物質均發(fā)生了不同程度的滲漏；麥角甾醇含量降低了92.0%,細胞膜的結構不完整；清除脂質過氧化物、自由基的能力下降。隨著農抗702濃度的提高,病菌的侵染因子羧甲基纖維素酶、多聚半乳糖醛酸酶、果膠甲基半乳糖醛酸酶的活性均有不同程度下降。農抗702處理水稻葉片后,明顯提高水稻抗紋枯病作用。農抗702處理水稻秧苗,稻苗體內的過氧化物酶,多酚氧化酶、苯丙氨酸解氨酶、過氧化氫酶等防御酶酶活性較高,對超氧化物歧化酶無顯著的影響。農抗702處理水稻葉片后,葉片中的p-1,3葡聚糖酶活顯著提高,上調的蛋白質點數較多,蛋白質點表達豐度差異顯著。低濃度農抗702促進水稻種子萌發(fā)、胚根和芽的生長,根系活力提高,但含糖量下降。種子中的淀粉酶活性、蛋白質含量隨農抗702濃度的升高先升后降。施加鏈霉菌702菌劑后土壤細菌和霉菌數量均有所減少,放線菌數量增加,降低了硝化細菌和亞硝化細菌的菌數,提高了好氣性纖維素分解菌菌數,而土壤微生物不同生理類群的變化,加速了土壤養(yǎng)分循環(huán),增強了水稻的養(yǎng)分吸收,從而促進水稻生長。綜上所述,結合多烯大環(huán)內酯類抗生素對真菌的作用機理,初步推斷農抗702對病原真菌的抑菌機理是：農抗702穿過細胞壁,與真菌細胞膜上的麥角甾醇相互結合形成麥角甾醇—抗生素復合物,增加菌體細胞膜的滲透性,進而使酶活性降低,供能不足,抑制菌體呼吸代謝、能量代謝,最終導致病原真菌的細胞膜破損,細胞器嚴重損傷,生長發(fā)育受到抑制,菌絲形態(tài)嚴重變形,直到死亡。另外,農抗702能夠誘導水稻產生抗性酶,促進種子的萌發(fā)。土壤配施鏈霉菌702提高了秧苗素質,促進有益微生物的生長,抑制有害微生物的生長。
[Abstract]:The 702 is Streptomyces isolated and screened with independent intellectual property rights of a strain from the soil of Jiangxi Agricultural University applied microbiology laboratory, the production of antifungal components of agricultural antibiotic 702 by structure identified as new compounds of polyene macrolide. This thesis mainly with Rhizoctonia solani as tested pathogens from the cells. Subcellular, physiological and biochemical, molecular biology and other aspects of the antibacterial mechanism of agricultural antibiotic 702 and preventing diseases and promoting growth mechanism, the main results are as follows: agricultural antibiotic 702 is light yellow powder like material, the melting point of 170-173.5 Deg. C, rotation [alpha (C =1.09]D23.7 =+4.3425. in MeOH), UV Vis spectra showed that at 318 nm. 303 nm 290nm, there are three typical absorption peaks, with polyene antibiotic spectrum; infrared spectra showed that it contains C=O, C=C, C-O, OH and CH2. Nongkang 702 stable for heat, the temperature above 60 DEG C activity began to decline in the strong acid; Under the condition of alkali activity is not stable, stable activity at pH 5-6. The research of agricultural growth of 702 anti mycelium, sclerotium formation and germination, inhibition of spore germination, electron microscope observation of the effect of micro morphology and structure of mycelia with. The results showed that the agricultural antibiotic 702 on mycelial growth inhibition and treatment of dry mycelium and cell membrane shrinkage, unclear contour, damaged organelles, serious injury, vacuolization. Formation of agricultural antibiotic 702 significantly inhibited the germination of Sclerotinia sclerotiorum, germination and spore. The agricultural antibiotic 702 after rhizoctoniasolani relative conductivity increased by 72.2%, protein, nucleic acid, Mg2+, K+ ions are intracellular substances leaking in different degrees; ergosterol content was reduced by 92%, the cell membrane structure is not complete; eliminating lipid peroxide, decreased ability of free radicals. With the increase of the concentration of agricultural antibiotic 702, bacteria infection factor Suo Jiaji Cellulase, polygalacturonase, pectin methyl galacturonate activity of all enzymes decreased in different degrees. The agricultural antibiotic 702 rice leaves after treatment, significantly improve the effect of rice sheath blight. The agricultural antibiotic 702 processing of rice seedling in rice seedlings, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, peroxidase and other defense enzymes high activity, no significant effect on superoxide dismutase. Nongkang 702 rice leaves after treatment, significantly improve the living p-1,3 glucanase in leaves, up-regulated protein spots more protein spots expressed significant difference. The low concentration of agricultural antibiotic 702 promote seed germination, radicle and shoot growth, root vigor improve, but sugar content decreased. The seeds of amylase activity, protein content increased with concentration of agricultural antibiotic 702 and then decreased. The number of soil bacteria and fungi were less applied Streptomyces 702 agent Less, the number of actinomycetes increased, reducing the number of bacteria nitrifying bacteria and denitrifying bacteria, improve aerobic cellulose decomposing bacteria number and soil microbial physiological groups change, accelerated soil nutrient cycling, enhance rice nutrient absorption, so as to promote the growth of rice. In summary, combined with the mechanism of polyene macrolide antibiotics on fungi, antibacterial mechanism preliminarily concluded the agricultural antibiotic 702 against pathogenic fungi is: agricultural antibiotic 702 through the cell wall, ergosterol and fungal cell membrane on ergosterol: antibiotic combine to form complexes, the increase of permeability of cell membrane, the enzyme activity decreased, energy supply shortage suppression bacterial respiratory metabolism, energy metabolism, resulting in damaged cell membrane of pathogenic fungi, organelles serious damage, growth inhibited the mycelial morphology severely deformed, until death. In addition, the agricultural antibiotic 702 can It is enough to induce rice to produce resistant enzymes and promote seed germination. Soil mixed Streptomyces 702 improves seedling quality, promotes beneficial microorganism growth and inhibits harmful microorganism growth.

【學位授予單位】：江西農業(yè)大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：S435.11;S476
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本文編號：1704427