Eceiza Mikel Vicente, Barco-Antoñanzas María, Gil-Monreal Miriam, Huybrechts Michiel, Zabalza Ana, Cuypers Ann, Royuela Mercedes
Institute for Multidisciplinary Research in Applied Biology (IMAB), Public University of Navarre, Pamplona, Spain.
Environmental Biology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
Front Plant Sci. 2023 Jan 6;13:1040456. doi: 10.3389/fpls.2022.1040456. eCollection 2022.
The aim of the present study was to elucidate the role of oxidative stress in the mode of action of acetolactate synthase (ALS) inhibiting herbicides. Two populations of S. Watson from Spain (sensitive and resistant to nicosulfuron, due to mutated ALS) were grown hydroponically and treated with different rates of the ALS inhibitor nicosulfuron (one time and three times the field recommended rate). Seven days later, various oxidative stress markers were measured in the leaves: HO, MDA, ascorbate and glutathione contents, antioxidant enzyme activities and gene expression levels. Under control conditions, most of the analysed parameters were very similar between sensitive and resistant plants, meaning that resistance is not accompanied by a different basal oxidative metabolism. Nicosulfuron-treated sensitive plants died after a few weeks, while the resistant ones survived, independently of the rate. Seven days after herbicide application, the sensitive plants that had received the highest nicosulfuron rate showed an increase in HO content, lipid peroxidation and antioxidant enzymatic activities, while resistant plants did not show these responses, meaning that oxidative stress is linked to ALS inhibition. A supralethal nicosulfuron rate was needed to induce a significant oxidative stress response in the sensitive population, providing evidence that the lethality elicited by ALS inhibitors is not entirely dependent on oxidative stress.
本研究的目的是阐明氧化应激在乙酰乳酸合酶（ALS）抑制性除草剂作用模式中的作用。从西班牙采集了两个种群的S. Watson（一个对烟嘧磺隆敏感，另一个由于ALS突变而对烟嘧磺隆具有抗性），将它们进行水培，并以不同剂量的ALS抑制剂烟嘧磺隆处理（分别为田间推荐剂量的1倍和3倍）。7天后，测定叶片中的各种氧化应激标志物：羟基自由基（HO）、丙二醛（MDA）、抗坏血酸和谷胱甘肽含量、抗氧化酶活性以及基因表达水平。在对照条件下，敏感植株和抗性植株之间大多数分析参数非常相似，这意味着抗性并不伴随着不同的基础氧化代谢。用烟嘧磺隆处理的敏感植株几周后死亡，而抗性植株存活，与剂量无关。施用除草剂7天后，接受最高烟嘧磺隆剂量的敏感植株的HO含量、脂质过氧化和抗氧化酶活性增加，而抗性植株未表现出这些反应，这意味着氧化应激与ALS抑制有关。需要超致死剂量的烟嘧磺隆才能在敏感种群中诱导出显著的氧化应激反应，这证明ALS抑制剂引起的致死性并不完全依赖于氧化应激。
