Aspergillus flavus is an important zoonotic pathogen and a well-known aflatoxin producer. Aspergillus flavus strains that are prevalent in Japanese environments are reported to be non-aflatoxigenic, although their aflatoxin productivity, especially among clinical isolates, has not been thoroughly investigated to date. In this study, we sequenced the genomes of ten strains of A. flavus isolated in Japan and compared their sequences with each other as well as with those of Aspergillus oryzae RIB40 and A. flavus NRRL3357. The phylogenetic analysis based on identified SNPs indicated that five strains were closer to A. oryzae RIB40 than to A. flavus NRRL3357. In contrast, of those isolates that were closer to A. flavus NRRL3357 than to A. oryzae RIB40, three were found to possess either the entire or partial aflatoxin biosynthesis gene cluster of NRRL3357-type. Furthermore, two of the three actually produced either aflatoxin B1 or an intermediate of the reaction leading to aflatoxin formation. Three of the ten strains we isolated were identified to possess part of the aflatoxin gene cluster, while five others retained the A. oryzae RIB40-type cluster. The genome data thus obtained may be further explored and utilized for comparative analysis of aflatoxin production in environmental and clinical isolates of A. flavus.

中文翻译：

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在日本临床分离的黄曲霉的比较基因组分析。

黄曲霉是一种重要的人畜共患病原体，也是著名的黄曲霉毒素生产者。据报道，在日本环境中普遍存在的黄曲霉菌株是非黄曲霉毒素的，尽管迄今为止尚未对其黄曲霉毒素的生产率，尤其是临床分离株中的黄曲霉毒素进行彻底研究。在这项研究中，我们对日本分离的十个黄曲霉菌株的基因组进行了测序，并将它们的序列以及米曲霉RIB40和黄曲霉NRRL3357的序列进行了比较。基于已鉴定的SNP的系统发育分析表明，五个菌株比米曲霉NRB3357更接近米曲霉RIB40。相反，在比黄曲霉NRRL3357更接近米曲霉RIB40的分离物中，发现三个具有NRRL3357型的全部或部分黄曲霉毒素生物合成基因簇。此外，三个中的两个实际上产生了黄曲霉毒素B1或导致黄曲霉毒素形成的反应中间体。我们分离出的十个菌株中的三个被鉴定为拥有一部分黄曲霉毒素基因簇，而其他五个则保留了米曲霉RIB40型簇。由此获得的基因组数据可以进一步探索，并用于比较黄曲霉的环境和临床分离物中黄曲霉毒素的产量。米粒RIB40型簇。由此获得的基因组数据可以进一步探索，并用于比较黄曲霉的环境和临床分离物中黄曲霉毒素的产量。米粒RIB40型簇。由此获得的基因组数据可以进一步探索，并用于比较黄曲霉的环境和临床分离物中黄曲霉毒素的产量。