Triadimefon, a type of triazole systemic fungicide, has been extensively used to control various fungal diseases. However, triadimefon could lead to severe environmental pollution, and even threatens human health. To eliminate triadimefon residues, a triadimefon-degrading bacterial strain TY18 was isolated from a long-term polluted site and was identified as Enterobacter hormaechei. Strain TY18 could grow well in a carbon salt medium with triadimefon as the sole nitrogen source, and could efficiently degrade triadimefon. Under triadimefon stress, a total of 430 differentially expressed genes (DEGs), including 197 up-regulated and 233 down-regulated DEGs, were identified in strain TY18 using transcriptome sequencing (RNA-Seq). Functional classification and enrichment analysis revealed that these DEGs were mainly related to amino acid transport and metabolism, carbohydrate transport and metabolism, small molecule and pyrimidine metabolism. Interestingly, the DEGs encoding monooxygenase and hydrolase activity acting on carbon–nitrogen were highly up-regulated, might be mainly responsible for the metabolism in triadimefon. Our findings in this work suggest that strain E. hormaechei TY18 could efficiently degrade triadimefon for the first time. They provide a great potential to manage triadimefon biodegradation in the environment successfully.

三唑酮是一种三唑类内吸性杀菌剂，广泛用于防治多种真菌病害。然而，三唑酮会导致严重的环境污染，甚至威胁人类健康。为了消除三唑酮残留，从长期污染场地分离得到一株三唑酮降解菌株TY18，经鉴定为霍马氏肠杆菌(Enterobacter hormaechei)。菌株TY18在以三唑酮为唯一氮源的碳盐培养基中生长良好，并能有效降解三唑酮。在三唑酮胁迫下，利用转录组测序（RNA-Seq）在菌株TY18中鉴定出总共430个差异表达基因（DEG），其中197个上调和233个下调DEG。功能分类和富集分析显示，这些差异表达基因主要与氨基酸转运和代谢、碳水化合物转运和代谢、小分子和嘧啶代谢相关。有趣的是，编码作用于碳氮的单加氧酶和水解酶活性的DEGs高度上调，可能主要负责三唑酮的代谢。我们在这项工作中的发现表明，菌株E. hormaechei TY18 首次能够有效降解三唑酮。它们为成功管理环境中的三唑酮生物降解提供了巨大的潜力。