Department d'Hortofructicultura, Botànica i Jardineria, Agrotecnio, Universitat de Lleida, 25198, Lleida, Spain.
Department of Agricultural Chemistry and Soil Science, University of Córdoba, Campus Rabanales, 14014, Córdoba, Spain.
Plant Physiol Biochem. 2021 Mar;160:51-61. doi: 10.1016/j.plaphy.2021.01.007. Epub 2021 Jan 8.
Papaver rhoeas biotypes displaying multiple herbicide resistance to ALS inhibitors and synthetic auxin herbicides (SAH) are spreading across Europe. In Spain, enhanced metabolism to imazamox was confirmed in one population, while cytochrome-P450 (P450) based metabolism to 2,4-D in another two. The objectives of this research were to further confirm the presence of P450 mediated enhanced metabolism and, if so, to confirm whether a putative common P450 is responsible of metabolizing both 2,4-D and imazamox. Metabolism studies were undertaken in five P. rhoeas populations with contrasted HR profiles (herbicide susceptible, only HR to ALS inhibitors, only HR to SAH, or multiple HR to both), and moreover, three different P450 inhibitors were used. The presence of enhanced metabolism to these SoA was confirmed in three more HR P. rhoeas populations. This study provides the first direct evidence that imazamox metabolism in these biotypes is P450-mediated, also in one population without an altered target site. Additionally, it was further confirmed that enhanced metabolism of 2,4-D in biotypes only HR to SAH or multiple HR to ALS inhibitors and SAH involves P450 as well. No metabolism was detected using the three inhibitors in all the herbicide-metabolizing P. rhoeas biotypes, suggesting that a common metabolic system involving P450s is responsible of degrading herbicides affecting both SoAs. Thus, selection pressure with either SAH or imidazolinone ALS inhibitors can select not only for resistance to each of them, but it can also confer cross-resistance between them in P. rhoeas.
具有多重草甘膦和合成生长素除草剂（SAH）抗性的罂粟生物型正在欧洲蔓延。在西班牙，一个种群中证实了对甲氧咪草烟的增强代谢，而另外两个种群中则证实了对 2,4-D 的细胞色素 P450（P450）代谢。本研究的目的是进一步确认是否存在 P450 介导的增强代谢，如果存在，则确认是否存在一个假定的共同 P450 负责代谢 2,4-D 和甲氧咪草烟。在具有不同 HR 特征（对除草剂敏感，仅对 ALS 抑制剂有 HR，仅对 SAH 有 HR，或对两者均有 HR）的五个罂粟种群中进行了代谢研究，此外，还使用了三种不同的 P450 抑制剂。在另外三个 HR 罂粟种群中证实了对这些 SoA 的增强代谢的存在。这项研究首次直接证明了这些生物型中对甲氧咪草烟的代谢是 P450 介导的，即使在没有靶标改变的种群中也是如此。此外，还进一步证实了，在仅对 SAH 有 HR 或对 ALS 抑制剂和 SAH 均有 HR 的生物型中，2,4-D 的增强代谢也涉及 P450。在所有具有除草剂代谢能力的罂粟生物型中，三种抑制剂均未检测到代谢产物，这表明一个涉及 P450 的共同代谢系统负责降解影响两种 SoA 的除草剂。因此，SAH 或咪唑啉酮 ALS 抑制剂的选择压力不仅可以选择对每种除草剂的抗性，还可以在罂粟中赋予它们之间的交叉抗性。
