CYP81A P450s armor Echinochloa phyllopogon against diverse and several herbicide chemistries. CYP81A substrate preferences can be a basis for cross-resistance prediction and management in E. phyllopogon and other related species. Metabolism-based herbicide resistance is a major threat to agriculture, as it is unpredictable and could extend resistance to different chemical groups and modes of action, encompassing existing, novel and to-be-discovered herbicides. Limited information on the enzymes involved in herbicide metabolism has hindered the prediction of cross-resistance in weeds. Members of CYP81A subfamily in multiple herbicide resistant (MHR) Echinochloa phyllopogon were previously identified for conferring cross-resistance to six unrelated herbicide classes. This suggests a critical role of CYP81As in endowing unpredictable cross-resistances in E. phyllopogon, thus the functions of all its nine putative functional CYP81A genes to 33 herbicides from 24 chemical groups were characterized. Ectopic expression in Arabidopsis thaliana identified the CYP81As that can confer resistance to multiple and diverse herbicides. The CYP81As were further characterized for their enzymatic functions in Escherichia coli. CYP81A expression in E. coli was optimized via modification of the N-terminus, co-expression with HemA gene and culture at optimal temperature. CYP81As metabolized its herbicide substrates into hydroxylated, N-/O-demethylated or both products. The cross-resistance pattern conferred by CYP81As is geared towards all chemical groups of acetolactate synthase inhibitors and is expanded to herbicides inhibiting photosystem II, phytoene desaturase, protoporphyrinogen oxidase, 4-hydroxyphenylpyruvate dioxygenase, and 1-deoxy-D-xylulose 5-phosphate synthase. Cross-resistance to herbicides pyrimisulfan, propyrisulfuron, and mesotrione was predicted and confirmed in MHR E. phyllopogon. This study demonstrated that the functional characterization of the key enzymes for herbicide metabolism could disclose the cross-resistance pattern and identify appropriate chemical options to manage the existing and unexpected cross-resistances in E. phyllopogon.

中文翻译：

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细胞色素 P450 CYP81A 亚家族的功能表征揭示了Echinochloa phyllopogon 中的交叉抗性模式。

CYP81A P450s 保护 Echinochloa phyllopogon 对抗多种除草剂化学物质。CYP81A 底物偏好可以作为 E. phyllopogon 和其他相关物种中交叉抗性预测和管理的基础。基于代谢的除草剂抗性是对农业的主要威胁，因为它是不可预测的，并且可以将抗性扩展到不同的化学组和作用方式，包括现有的、新型的和有待发现的除草剂。参与除草剂代谢的酶的有限信息阻碍了杂草交叉抗性的预测。多重除草剂抗性 (MHR) Echinochloa phyllopogon 中的 CYP81A 亚科成员先前被鉴定为对六种不相关的除草剂类别具有交叉抗性。这表明 CYP81A 在赋予 E. phyllopogon 不可预测的交叉抗性中的关键作用，因此表征了其所有 9 个推定的功能性 CYP81A 基因对来自 24 个化学组的 33 种除草剂的功能。拟南芥中的异位表达鉴定了可赋予对多种除草剂抗性的 CYP81As。CYP81As 在大肠杆菌中的酶功能得到了进一步的表征。CYP81A 在大肠杆菌中的表达通过修饰 N 末端、与 HemA 基因共表达和在最佳温度下培养来优化。CYP81As 将其除草剂底物代谢为羟基化、N-/O-去甲基化或两种产物。CYP81As 赋予的交叉耐药模式适用于乙酰乳酸合酶抑制剂的所有化学基团，并扩展到抑制光系统 II、八氢番茄红素去饱和酶、原卟啉原氧化酶、4-羟苯基丙酮酸双加氧酶和 1-脱氧-D-木酮糖 5-磷酸合酶的除草剂. 在 MHR E. phyllopogon 中预测并证实了对除草剂嘧磺隆、丙嘧磺隆和甲基磺草酮的交叉耐药性。该研究表明，除草剂代谢关键酶的功能表征可以揭示交叉抗性模式并确定适当的化学选择来管理 E. phyllopogon 中现有的和意外的交叉抗性。在 MHR E. phyllopogon 中预测并证实了对除草剂嘧磺隆、丙嘧磺隆和甲基磺草酮的交叉耐药性。该研究表明，除草剂代谢关键酶的功能表征可以揭示交叉抗性模式并确定适当的化学选择来管理 E. phyllopogon 中现有的和意外的交叉抗性。在 MHR E. phyllopogon 中预测并证实了对除草剂嘧磺隆、丙嘧磺隆和甲基磺草酮的交叉耐药性。该研究表明，除草剂代谢关键酶的功能表征可以揭示交叉抗性模式并确定适当的化学选择来管理 E. phyllopogon 中现有的和意外的交叉抗性。