ABSTRACT A collection of 500 Aspergillus flavus isolates from four sesame varieties (S-34, S-35, S-38, and S-39) that were planted in field plots in the Mississippi Delta and in the Florida Panhandle were investigated because of low-level aflatoxin contamination detected in sesame seeds. A rapid molecular fingerprinting method was developed to assess the influence of prior applications of the atoxigenic Afla-Guard® biocontrol product whose active strain is NRRL21882 on the A. flavus populations within each field plot. Depending on sesame seed sampled, 66.7% to 95.9% of A. flavus isolates from Mississippi belonged to the NRRL21882 genotype, which lacks the aflatoxin and cyclopiazonic acid biosynthesis gene clusters. In contrast, only 5.0% to 32.5% of the isolates from Florida had lost both gene clusters. The high incidence of NRRL21882-like A. flavus in Mississippi sesame samples can be attributed to prior applications of Afla-Guard® in that local area. The results suggest the adaptability of this particular type of atoxigenic A. flavus biocontrol strain in the field.

中文翻译：

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NRRL21882 样（Afla-Guard®）黄曲霉在密西西比三角洲研究领域种植的芝麻上的流行率

摘要 对种植在密西西比三角洲和佛罗里达狭长地带的田间地块的四个芝麻品种（S-34、S-35、S-38 和 S-39）的 500 - 在芝麻中检测到黄曲霉毒素污染。开发了一种快速分子指纹识别方法来评估先前应用无毒 Afla-Guard® 生物防治产品（其活性菌株为 NRRL21882）对每个田地内的黄曲霉种群的影响。根据采样的芝麻种子，来自密西西比州的 66.7% 至 95.9% 的黄曲霉分离株属于 NRRL21882 基因型，该基因型缺乏黄曲霉毒素和环吡嗪酸生物合成基因簇。相比之下，佛罗里达州仅有 5.0% 至 32.5% 的分离株丢失了两个基因簇。NRRL21882 样 A 的高发生率。密西西比芝麻样品中的黄曲霉病可归因于先前在该地区应用 Afla-Guard®。结果表明这种特殊类型的无毒黄曲霉生物防治菌株在田间具有适应性。