Aldo-keto Reductase Metabolizes Glyphosate and Confers Glyphosate Resistance in Echinochloa colona1
Aldo-keto Reductase Metabolizes Glyphosate and Confers Glyphosate Resistance in Echinochloa colona1
复制标题
醛酮还原酶代谢草甘膦并赋予稗草抗性
DOI：
10.1104/pp.19.00979
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发表时间：
2019-12-01
期刊：
影响因子：
7.4
通讯作者：
Powles, Stephen
中科院分区：
文献类型：
--
作者：
Pan, Lang;Yu, Qin;Powles, Stephen
植物代谢酶醛酮还原酶已经进化到能够在抗草甘膦杂草中代谢草甘膦。草甘膦是世界上最常用的除草剂，控制着广泛的植物物种，主要是因为植物几乎没有代谢（解毒）草甘膦的能力。草甘膦的大量使用导致了全球范围内草甘膦抗性（GR）杂草物种的进化，包括具有经济破坏性的草甘膦杂草刺青藻（Echinochloa colona）。澳大利亚大肠杆菌种群已经进化出对草甘膦的抗性，其机制未知，与草甘膦靶酶5-烯醇丙酮酰莽草酸-3- p合成酶无关。从该群体中分离出GR和草甘膦敏感品系，用于抗性基因的发现。RNA测序分析和表型/基因型验证实验表明，一个醛酮还原酶（AKR）序列在GR中表达量和合成AKR活性均高于S。两个全长AKR （EcAKR4-1和EcAKR4-2）互补转录本在GR和S植株中序列相同，但在GR植株中表达上调。过表达EcAKR4-1的水稻愈伤组织和幼苗对草甘膦具有抗性，且AKR活性增加。在大肠杆菌中表达的EcAKR4-1能够代谢草甘膦生成氨基甲基膦酸和乙醛酸盐。与这些结果一致，GR E. colona植物表现出增强的将草甘膦解毒为氨基甲基膦酸和乙醛酸盐的能力。结构模型预测草甘膦与EcAKR4-1结合进行氧化，对EcAKR4-1转基因水稻幼苗的代谢组学分析揭示了草甘膦代谢可能涉及的氧化还原途径。我们的研究为植物AKR代谢草甘膦的进化提供了直接的实验证据，从而赋予草甘膦抗性。
The plant metabolic enzyme aldo-keto reductase has evolved to metabolize glyphosate in a glyphosate-resistant weed speciesGlyphosate, the most commonly used herbicide in the world, controls a wide range of plant species, mainly because plants have little capacity to metabolize (detoxify) glyphosate. Massive glyphosate use has led to world-wide evolution of glyphosate-resistant (GR) weed species, including the economically damaging grass weed Echinochloa colona. An Australian population of E. colona has evolved resistance to glyphosate with unknown mechanisms that do not involve the glyphosate target enzyme 5-enolpyruvylshikimate-3-P synthase. GR and glyphosate-susceptible (S) lines were isolated from this population and used for resistance gene discovery. RNA sequencing analysis and phenotype/genotype validation experiments revealed that one aldo-keto reductase (AKR) contig had higher expression and higher resultant AKR activity in GR than S plants. Two full-length AKR (EcAKR4-1 and EcAKR4-2) complementary DNA transcripts were cloned with identical sequences between the GR and S plants but were upregulated in the GR plants. Rice (Oryza sativa) calli and seedlings overexpressing EcAKR4-1 and displaying increased AKR activity were resistant to glyphosate. EcAKR4-1 expressed in Escherichia coli can metabolize glyphosate to produce aminomethylphosphonic acid and glyoxylate. Consistent with these results, GR E. colona plants exhibited enhanced capacity for detoxifying glyphosate into aminomethylphosphonic acid and glyoxylate. Structural modeling predicted that glyphosate binds to EcAKR4-1 for oxidation, and metabolomics analysis of EcAKR4-1 transgenic rice seedlings revealed possible redox pathways involved in glyphosate metabolism. Our study provides direct experimental evidence of the evolution of a plant AKR that metabolizes glyphosate and thereby confers glyphosate resistance.