The Fusarium mycotoxin deoxynivalenol (DON) is typically controlled by fungicides. Here, we report DON detoxification using enzymes from the highly active Devosia strain D6-9 which degraded DON at 2.5 μg/min/108 cells. Strain D6-9 catabolized DON to 3-keto-DON and 3-epi-DON, completely removing DON in wheat. Genome analysis of three Devosia strains (D6-9, D17, and D13584), with strain D6-9 transcriptomes, identified three genes responsible for DON epimerization. One gene encodes a quinone-dependent DON dehydrogenase QDDH which oxidized DON into 3-keto-DON. Two genes encode the NADPH-dependent aldo/keto reductases AKR13B2 and AKR6D1 that convert 3-keto-DON into 3-epi-DON. Recombinant proteins expressed in Escherichia coli efficiently degraded DON in wheat grains. Molecular docking and site-directed mutagenesis revealed that residues S497, E499, and E535 function in QDDH's DON-oxidizing activity. These results advance potential microbial and enzymatic elimination of DON in agricultural samples and lend insight into the underlying mechanisms and molecular evolution of DON detoxification.

中文翻译：

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醌依赖性脱氢酶和两种NADPH依赖性醛/酮还原酶通过Devosia菌株中的差向异构化作用使小麦中的脱氧雪茄烯醇解毒。

镰刀菌霉菌毒素脱氧雪腐烯醇（DON）通常由杀真菌剂控制。在这里，我们报告使用高活性Devosia菌株D6-9的酶进行DON解毒，该酶以2.5μg/ min / 108细胞降解DON。D6-9菌株将DON分解代谢为3-keto-DON和3-epi-DON，完全清除了小麦中的DON。带有D6-9转录组的三个Devosia菌株（D6-9，D17和D13584）的基因组分析确定了负责DON差向异构化的三个基因。一个基因编码醌依赖性的DON脱氢酶QDDH，该酶将DON氧化为3-酮-DON。两个基因编码NADPH依赖的醛/酮还原酶AKR13B2和AKR6D1，它们将3-酮-DON转化为3-表-DON。在大肠杆菌中表达的重组蛋白可有效降解小麦籽粒中的DON。分子对接和定点诱变显示残基S497，E499，和E535在QDDH的DON氧化活性中起作用。这些结果促进了农业样品中DON潜在的微生物和酶促消除，并深入了解了DON解毒的潜在机理和分子进化。