In warm regions, agricultural fields are occupied by complex Aspergillus flavus communities composed of isolates in many vegetative compatibility groups (VCGs) with varying abilities to produce highly toxic, carcinogenic aflatoxins. Aflatoxin contamination is reduced with biocontrol products that enable atoxigenic isolates from atoxigenic VCGs to dominate the population. Shifts in VCG frequencies similar to those caused by the introduction of biocontrol isolates were detected in Sonora, Mexico, where biocontrol is not currently practiced. The shifts were attributed to founder events. Although VCGs reproduce clonally, significant diversity exists within VCGs. Simple sequence repeat (SSR) fingerprinting revealed that increased frequencies of VCG YV150 involved a single haplotype. This is consistent with a founder event. Additionally, great diversity was detected among 82 YV150 isolates collected over 20 years across Mexico and the United States. Thirty‐six YV150 haplotypes were separated into two populations by Structure and SplitsTree analyses. Sixty‐five percent of isolates had MAT1‐1 and belonged to one population. The remaining had MAT1‐2 and belonged to the second population. SSR alleles varied within populations, but recombination between populations was not detected despite co‐occurrence at some locations. Results suggest that YV150 isolates with opposite mating‐type have either strongly restrained or lost sexual reproduction among themselves.

中文翻译：

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创始人事件影响黄曲霉种群的结构。


在温暖地区，农田被复杂的黄曲霉群落占据，这些群落由许多营养相容性群 (VCG) 中的分离株组成，具有不同的产生剧毒、致癌黄曲霉毒素的能力。生物防治产品可以减少黄曲霉毒素污染，使来自产毒 VCG 的产毒分离株在种群中占主导地位。在墨西哥索诺拉州检测到 VCG 频率的变化与引入生物防治菌株引起的变化类似，该地区目前尚未实施生物防治。这些转变归因于创始人事件。尽管 VCG 可以克隆繁殖，但 VCG 内存在显着的多样性。简单序列重复 (SSR) 指纹分析表明，VCG YV150 频率的增加涉及单一单倍型。这与创始人事件一致。此外，20 年来在墨西哥和美国收集的 82 个 YV150 分离株中发现了巨大的多样性。通过结构和 SplitsTree 分析将 36 个 YV150 单倍型分为两个群体。 65% 的分离株具有MAT1-1并且属于一个种群。其余的具有MAT1-2 ，属于第二人群。 SSR 等位基因在种群内有所不同，但尽管在某些位置同时出现，但并未检测到种群之间的重组。结果表明，具有相反交配型的 YV150 分离株彼此之间要么受到强烈限制，要么丧失了有性生殖。