Department of Crop and Soil Science, Oregon State University, Corvallis, OR, USA.
Department of Plant Sciences, University of California, Davis, Davis, CA, USA.
Pest Manag Sci. 2019 Jun;75(6):1663-1670. doi: 10.1002/ps.5284. Epub 2019 Jan 28.
Poa annua is a widespread winter annual weed species in California. Recently, poor control of this species with glyphosate was reported by growers in an almond orchard in California with a history of repetitive glyphosate use. The objectives of this research were to evaluate the level of glyphosate resistance in a developed S P. annua line (R) and identify the mechanisms of resistance involved.
Whole-plant dose-response experiments confirmed glyphosate resistance in R, which required 18-fold more glyphosate to achieve a 50% growth reduction compared with a susceptible line (S), results that were supported by the lower shikimate accumulation observed in R compared with S. No differences in glyphosate absorption, translocation, or metabolism were observed, suggesting that non-target-site mechanisms of resistance are not involved in the resistance phenotype. A missense single nucleotide polymorphism was observed in EPSPS coding position 106 in R, resulting in a leucine to proline substitution. This polymorphism was observed exclusively in P. supina EPSPS homeologs. A seven-fold increase in the number of copies of EPSPS alleles was observed in R compared with S.
We report the first case of glyphosate resistance associated with both EPSPS duplication and target-site mutation at position 106, leading to high levels of glyphosate resistance in the allotetraploid weed species Poa annua L. Data obtained in this research will be useful for the development of diagnostic tools for rapid glyphosate resistance identification, monitoring and containment. © 2018 Society of Chemical Industry.
雀麦是加利福尼亚州广泛分布的冬季一年生杂草。最近，加利福尼亚州杏仁果园的种植者报告称，由于重复使用草甘膦，这种物种的防治效果很差。本研究的目的是评估已发育的雀麦（R）对线磷抗性的水平，并确定涉及的抗性机制。
全株剂量反应实验证实 R 具有草甘膦抗性，与敏感系（S）相比，需要 18 倍的草甘膦才能使生长减少 50%，这一结果得到了 R 中观察到的莽草酸积累较低的支持。未观察到草甘膦吸收、转运或代谢的差异，这表明非靶标位点机制不参与抗性表型。在 R 中观察到 EPSPS 编码位置 106 处存在错义单核苷酸多态性，导致亮氨酸到脯氨酸取代。这种多态性仅在 P. supina EPSPS 同源物中观察到。与 S 相比，R 中 EPSPS 等位基因的拷贝数增加了七倍。
我们报告了第一个与 EPSPS 重复和 106 位靶标突变相关的草甘膦抗性案例，导致四倍体杂草雀麦对线磷产生高水平的抗性。本研究获得的数据将有助于开发快速草甘膦抗性鉴定、监测和控制的诊断工具。© 2018 化学工业协会。
