El-Mastouri Zakia, Košnarová Pavlína, Hamouzová Kateřina, Alimi Ezzedine, Soukup Josef
Department of Agroecology and Crop Production, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czechia.
Maghreb Phytotest, Tunis, Tunisia.
Front Plant Sci. 2024 Feb 6;15:1331725. doi: 10.3389/fpls.2024.1331725. eCollection 2024.
Rigid ryegrass ( Gaud.) is one of the most troublesome weeds in Moroccan and Tunisian cereal crop fields. In total, 19 rigid ryegrass field populations were randomly selected in northern wheat crop areas of Morocco and Tunisia to examine the patterns of herbicide resistance to acetolactate synthase (ALS)- and acetyl-CoA carboxylase (ACCase)-inhibiting herbicides. Greenhouse experiments confirmed reduced sensitivity to ALS- and/or ACCase-inhibiting herbicides in all populations. The occurrence of target-site resistance (TSR) was tested using high-throughput genotyping. The advent of next-generation sequencing (NGS) has enabled easy identification of causal mutations and confirmed the presence of ALS and ACCase mutations at specific codons conferring TSR. Thirteen populations showed resistance to ALS-inhibiting herbicides associated with point mutations in positions Pro-197-Thr, Pro-197-Ser, Pro-197-Leu, Pro-197-Gln and Trp-574-Leu, while resistance to ACCase-inhibiting herbicides was detected in 18 populations in positions Asp-2078-Val, Trp-2027-Cys, Ile-1781-Leu, Gly-2096-Ala, and Ile-2041-Asn of the enzymes conferring TSR. Additionally, dose-response experiments with pyroxsulam applied after the inhibition of cytochrome P450 monooxygenase by malathion showed an increase in sensitivity in two out of seven highly resistant (HR) rigid ryegrass populations. This demonstrates the presence of non-target-site resistance (NTSR) in some ryegrass populations. Further evidence of NTSR was investigated in dose-response experiments with pyroxsulam, following pretreatment with the glutathione -transferase (GST) inhibitor 4-chloro-7-nitrobenzoxadiazole (NBD-Cl), which partially reversed resistance in only a few individuals of two populations. Hence, our study confirms the existence of multiple and cross-resistance to ALS- and ACCase-inhibiting herbicides in from Morocco and Tunisia with both TSR and NTSR mechanisms. These results emphasize local resistance management as an important tool to detect and mitigate gene flow from rigid ryegrass populations where resistance has evolved.
硬直黑麦草（Gaud.）是摩洛哥和突尼斯谷类作物田最棘手的杂草之一。总共在摩洛哥和突尼斯北部小麦种植区随机选取了19个硬直黑麦草田间种群，以研究对乙酰乳酸合成酶（ALS）和乙酰辅酶A羧化酶（ACCase）抑制型除草剂的抗药性模式。温室试验证实，所有种群对ALS和/或ACCase抑制型除草剂的敏感性均降低。使用高通量基因分型检测靶标位点抗性（TSR）的发生情况。下一代测序（NGS）技术的出现使得能够轻松鉴定因果突变，并证实了在特定密码子处存在赋予TSR的ALS和ACCase突变。13个种群对ALS抑制型除草剂具有抗性，与Pro-197-Thr、Pro-197-Ser、Pro-197-Leu、Pro-197-Gln和Trp-574-Leu位置的点突变有关，而在18个种群中检测到对ACCase抑制型除草剂的抗性，位于赋予TSR的酶的Asp-2078-Val、Trp-2027-Cys、Ile-1781-Leu、Gly-2096-Ala和Ile-2041-Asn位置。此外，在马拉硫磷抑制细胞色素P450单加氧酶后施用唑啉草酯的剂量反应试验表明，在7个高抗（HR）硬直黑麦草种群中有2个种群的敏感性增加。这证明了一些黑麦草种群中存在非靶标位点抗性（NTSR）。在用谷胱甘肽-S-转移酶（GST）抑制剂4-氯-7-硝基苯并恶二唑（NBD-Cl）预处理后，通过唑啉草酯的剂量反应试验进一步研究了NTSR的证据，该试验仅在两个种群的少数个体中部分逆转了抗性。因此，我们的研究证实了来自摩洛哥和突尼斯的硬直黑麦草对ALS和ACCase抑制型除草剂存在多种抗性和交叉抗性，且存在TSR和NTSR机制。这些结果强调了局部抗性管理作为一种重要工具，用于检测和减轻抗性已进化的硬直黑麦草种群的基因流动。
