Annual sedge (Cyperus compressus L.) populations with resistance to halosulfuron were identified in turfgrass at two new locations in Georgia. Research was conducted to evaluate (1) resistance levels to two acetolactate synthase (ALS) inhibitors, (2) ALS enzyme susceptibility, (3) genetic differences associated with resistance, and (4) differential levels of ALS gene expression in these biotypes. In dose–response experiments, the biotypes were >160 times resistant to halosulfuron but only 12 times more resistant to imazaquin compared with a susceptible biotype. In vitro enzyme assays indicated that resistant (R) biotypes required 6.1-fold greater concentrations of imazaquin to reduce ALS activity 50% compared with the susceptible (S) biotype. Both R biotypes had a similar Pro-197-Ser amino acid substitution in the ALS gene that confers resistance to sulfonylureas. Compared with the S biotype, R biotypes had 4.4 times higher ALS gene expression than the S biotype. No differences in gene copy number were found between any biotypes for the ALS gene. Overall, ALS-resistant C. compressus selected by halosulfuron use in turfgrass may be exhibiting partial susceptibility to imazaquin but complete resistance to sulfonylureas. Differential levels of susceptibility to ALS inhibitors for these biotypes are associated with the Pro-197-Ser substitution and enhanced expression of the ALS gene.

中文翻译：

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基因表达和靶位点突变与来自佐治亚州的一年生莎草（Cyperus compressus）生物型对 ALS 抑制剂的抗性有关

一年生莎草（香附L.) 在乔治亚州两个新地点的草坪草中鉴定出对卤磺隆具有抗性的种群。进行研究以评估 (1) 对两种乙酰乳酸合酶 (ALS) 抑制剂的抗性水平，(2) ALS 酶易感性，(3) 与抗性相关的遗传差异，以及 (4)肌萎缩侧索硬化症这些生物型中的基因表达。在剂量反应实验中，与易感生物型相比，这些生物型对卤磺隆的耐药性 > 160 倍，但对灭草喹的耐药性仅高 12 倍。体外酶测定表明，与易感 (S) 生物型相比，抗性 (R) 生物型需要 6.1 倍的灭草喹浓度才能将 ALS 活性降低 50%。两种 R 生物型都具有相似的 Pro-197-Ser 氨基酸取代肌萎缩侧索硬化症对磺脲类药物具有抗性的基因。与 S 生物型相比，R 生物型的高 4.4 倍肌萎缩侧索硬化症基因表达高于S生物型。没有发现任何生物型之间的基因拷贝数差异肌萎缩侧索硬化症基因。总体而言，抗 ALSC. compressus卤代磺隆在草坪草中的应用可能表现出对灭草喹的部分敏感性但对磺酰脲类的完全抗性。这些生物型对 ALS 抑制剂的不同敏感性水平与 Pro-197-Ser 取代和增强的肌萎缩侧索硬化症基因。