Three putative resistant (R1, R2, R3) and one susceptible (S) Lolium rigidum populations originating from Greece were studied for resistance to ALS and ACCase inhibiting herbicides, using whole plant, sequencing of als and accase gene, and in vitro ALS activity assays. The S and two R (R1, R2) populations were also evaluated for fitness in competition with wheat. The whole plant assay indicated unsatisfactory control of the R populations with mesosulfuron-methyl + iodosulfuron-methyl or pinoxaden application, whereas sequencing of the als gene revealed that all ALS-resistant individuals had a Pro-197 substitution by Leu, Glu, Ser, Ala, Thr, or Gln. In addition, the accase gene of all pinoxaden resistant individuals had an Ile-2041 substitution by Asn or Thr. Furthermore, sequencing of the individuals surviving mesosulfuron-methyl + iodosulfuron-methyl or pinoxaden treatment revealed co-existence of point mutations in the accase or als genes, respectively, demonstrating multiple resistance. The in vitro activity of the ALS enzyme confirmed that resistance to mesosulfuron-methyl + iodosulfuron-methyl was due altered target-site. The recorded higher vigor and greater competitive ability of S population against wheat as compared with that of the R populations suggests an associated fitness cost with multiple resistance.

中文翻译：

---

黑麦草对ALS和ACCase抑制性除草剂的多重抗性机制及其对植物适应性的影响

研究了源自希腊的三个推定抗性（R1、R2、R3）和一个易感（S）黑麦草种群对 ALS 和 ACCase 抑制性除草剂的抗性，使用整株植物、als 和 accase 基因测序以及体外 ALS 活性测定. 还评估了 S 和两个 R (R1, R2) 种群在与小麦竞争中的适应性。全株试验表明，甲基磺隆+甲基碘磺隆或吡咯沙登对R种群的控制不令人满意，而als基因的测序显示所有ALS抗性个体的Pro-197被Leu、Glu、Ser、Ala取代、Thr 或 Gln。此外，所有抗匹诺沙登个体的 accase 基因都有一个 Ile-2041 被 Asn 或 Thr 取代。此外，对甲基磺隆+甲基碘磺隆或吡诺沙丁治疗后幸存的个体进行测序，结果分别揭示了accase或als基因中点突变的共存，证明了多重耐药性。ALS 酶的体外活性证实了对甲基磺隆 + 甲基碘磺隆的抗性是由于靶位点的改变。与 R 群体相比，S 群体对小麦的记录更高的活力和更强的竞争能力表明与多重抗性相关的适应度成本。