Amplification of herbicide target genes conferring naturally evolved resistance in weed species is one of the novel and more recently known mechanisms of resistance. Numerous agriculturally important dicot and monocot weeds, including Palmer amaranth (Amaranthus palmeri), common waterhemp (Amaranthus tuberculatus) and Italian ryegrass (Lolium multiflorum), have evolved resistance to glyphosate via this mechanism. Specifically, the extrachromosomal amplification of the 5‐enopyruvlyshikimate‐3‐phosphate synthase (EPSPS) gene, the molecular target of glyphosate, was found to be the basis for glyphosate resistance in Amaranthus weeds, for example Palmer amaranth and common waterhemp. Nonetheless, the mechanism of extrachromosomal amplification of the EPSPS gene was different in these weeds. These extrachromosomal elements are newly identified genetic components and represent a paradigm shift in genetics to provide an adaptive advantage to organisms to withstand stress. Also, the extrachromosomal amplified copies are touted to be unstable in many organisms, due to their unpredictable behaviour during mitosis or meiosis, suggesting that they may have not integrated into the host genome. Therefore, it is reasonable to hypothesise that, in the absence of selection, the number of EPSPS copies may dissipate leading to the reversal of glyphosate resistance to susceptibility.

中文翻译：

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染色体外环状DNA介导的EPSPS基因扩增的非孟德尔遗传能否为逆转对草甘膦的抗性提供机会？

赋予杂草物种自然进化抗性的除草剂靶基因的扩增是新的和最近已知的抗性机制之一。许多农业上重要的双子叶植物和单子叶植物杂草，包括棕榈（菜（Amaranthus palmeri），普通大麻（Amaranthus tuberculatus）和意大利黑麦草（Lolium multiflorum），都通过这种机制对草甘膦产生了抗药性。具体来说，是5-烯丙基丙酮酸ki酸酯-3-磷酸合酶（EPSPS）的染色体外扩增）基因，草甘膦的分子靶标，被发现是A菜杂草中抗草甘膦的基础，例如Palmer a菜和普通common。但是，这些杂草中EPSPS基因的染色体外扩增机理不同。这些染色体外元件是新近鉴定的遗传成分，代表了遗传学的范式转变，从而为生物体提供了承受压力的适应性优势。此外，由于在有丝分裂或减数分裂期间它们的不可预测的行为，染色体外扩增的拷贝在许多生物中被吹捧为不稳定的，这表明它们可能尚未整合到宿主基因组中。因此，可以合理地假设，在没有选择的情况下，EPSPS的数量 拷贝可能消散，导致草甘膦​​对药敏性的抵抗力逆转。