不产毒黄曲霉菌对产毒黄曲霉菌产毒抑制效果分析

Atoxigenic Aspergillus flavus Competitively Reduce Aflatoxin Production by the Toxigenic Aspergillus flavus

本实验6株菌分离自广东、山东、辽宁和湖北四省的花生土壤中，通过形态学和分子生物学鉴定均为黄曲霉菌，HPLC测定其产毒能力，其中GZ-6为产毒菌，GZ-15、WF-5、WF-20、JZ-2和YC-8为不产毒菌。分别以花生和玉米为培养基，将不产毒黄曲霉菌和产毒菌（孢子浓度：104：105或105：105）进行混合培养，测定不产毒菌对产毒黄曲霉产毒的抑制效果。结果显示：不产毒菌对产毒菌产毒的抑制率随着其孢子浓度的增加而明显加强，当孢子浓度比为105：105（不产毒菌：产毒菌）时，5株不产毒菌在玉米培养基上对产毒菌产毒的抑制率为34．55％-75．94％，在花生培养基上对产毒菌产毒的抑制率为38．03％～83．03％，其中WF-5、WF-20和GZ-15这三株不产毒菌对产毒黄曲霉产毒的抑制效果均达到75．00％以上，可以作为田间防治黄曲霉毒素污染的候选菌株。

Six Aspergillus flavus isolates were collected from Guangdong, Shandong, Liaoning and Hubei Provinces in China, and identified through morphology and molecular biology. The aflatoxin production ability of these isolates was detected by HPLC. The results showed that GZ-6 was a toxigenic isolate, while GZ-15, WF-5, WF-20, JZ-2 and YC-8 were atoxigenic. To analyze the inhibitory effect of the atoxigenic strain on the toxigenic strain, the atoxigenic strain with the toxigenic strain were co-inoculated at t he spore concentration ratio of 104：105 or 105：105 on peanuts and maize, respectively. The results showed that the inhibitory effect of the atoxigenic strain on the toxigenic strain was significantly enhanced as the spore concentration increased. At the ratio of 105：105 （atoxigenic： toxigenic）, the five atoxigenic A. flavus reduced 34.55-75.94% aflatoxin production by GZ-6 on maize and 38.03% -83.03% afiatoxin production by GZ-6 on peanuts. WF-5, WF-20 and GZ-15 could prevent more than 75.00% aflatoxin production by GZ-6 and could probably be exploited as effective agents for aflatoxin control in field.