生态经济型作物花生和土壤中黄曲霉生防菌的筛选研究.pdfVIP

摘 要 本试验对土壤与花生样品进行真菌选择性分离，通过传统方法鉴定出黄曲霉 菌，利用紫外荧光法与高效液相色谱法对黄曲霉菌是否产毒以及产毒能力进行检 测，对不产毒菌株进行生长速度、产孢量、平板对峙、植株根际存活能力、抑制病 原菌的盆栽效果的测定，筛选出一株具有高竞争性的生防菌株，并在基因水平上研 究了其不产毒机制。 得到了以下结果：从土壤和花生样品中共分离鉴定出 68 株黄曲霉菌，其中土 壤中共 52 株，花生中共 16 株。68 株黄曲霉菌中，检测出不产毒菌株 27 株，产毒 黄曲霉菌 41 株，其中有三株高产毒菌株 T5-14 、T5-8 与 T3-2 。比较了 SDA 、YES 与 CYA 三种液体培养基产毒能力，结果表明 YES 液体培养基是黄曲霉产毒最高的 培养基。筛选出一株高竞争性的生防菌株 T5-1 ，能够有效抑制土壤中产毒黄曲霉菌 群体的增长。对生防菌株 T5-1 进行 5.8S rDNA 序列分析，将测序结果在 GenBank 数据库进行同源有哪些信誉好的足球投注网站，其 5.8S rDNA 序列与曲霉属黄曲霉（Aspergillus flavus ）同源 率达 99% ，进一步验证其为黄曲霉。该菌株的毒素合成基因从基因 aflF 至基因 aflD 出现缺失，即缺失黄曲霉毒素合成基因 aflF 、aflU 、aflT 、aflC 、aflD 。其中基因 aflF 、 aflC 与 aflD 在黄曲霉毒素生物合成过程中具有重要作用，因此该菌株不能合成黄曲 霉毒素。 关键词：花生；黄曲霉；黄曲霉毒素；鉴定；基因 - I - Abstract The aim of this study was to isolate fungi from soil and peanuts, and Aspergillus flavus strains were identified by traditional methods. Applied ultraviolet fluorescence method and High-Performance Liquid Chromatography （HPLC ） to screen aflatoxicoge- nic strains from above Aspergillus flavus . There were 5 biocontrol characters of aflatoxin-nonproducing isolates （including growth, amount of sporulation, confrontation, survive ability in rhizospher, pot experiment ） to screen isolates with strong biocontrol potential capability, then we studied mechanism of aflatoxin-nonproducing at the level of gene. The specific results were as fellows: 68 strains of Aspergillus flavus were isolated and identified from soil and peanuts, including 52 strains in soil and 16 strains in peanuts. 27 strains produced of aflatoxin, and 40 strains did not produce aflatoxin. Three isolates of A.flavus T5-14, T5-8 and T3-2 produced higher amount of aflatoxin. Then we evaluatied three different flui