Identification and Mapping of Cross-Resistance Patterns to ALS-Inhibitors in Greater Beggarticks (Bidens spp.)

ABSTRACT: Greater beggarticks (Bidens pilosa and Bidens subalternans) biotypes have been under selection pressure of ALS-inhibitors since early 90’s in Brazil. The objectives of this work were to investigate whether there are different cross-resistance patterns among ALS-inhibitors herbicides in Bidens spp. biotypes; to understand the geographic distribution of resistance patterns in grains producing regions in Brazil; and evaluate the possibility of multiple resistance to ALS-inhibitors, EPSPs inhibitor and photosystem II inhibitors. Dose-response experiments were carried out with imazethapyr, chlorimuron and diclosulam in three populations. Sensibility to others 34 populations both from Paraná State (PR) and from others Brazilian regions were also evaluated. The dose-response assay revealed cross-resistance with different patterns. One population was resistant to all three herbicides, the second population was tolerant to both imazethapyr and chlorimuron, but not to diclosulam, while a third population was resistant merely to imazethapyr. The results exhibited different cross-resistance patterns, since they can be found in other Bidens spp. populations. However, no relationship was observed between geographic areas where samples were collected and resistance patterns. Conclusively, the most frequent resistance pattern was R2 (resistance to imazethapyr, chlorimuron and diclosulam).

摘要：自20世纪90年代初起，巴西的大狼把草（Bidens pilosa与Bidens subalternans）生物型便持续处于乙酰乳酸合酶（ALS）抑制剂类除草剂的选择压力之下。本研究旨在明确鬼针草属（Bidens spp.）生物型对ALS抑制剂类除草剂存在何种差异化的交互抗性模式，解析巴西粮食产区内此类抗性模式的地理分布特征，并评估其对ALS抑制剂、5-烯醇式丙酮酰莽草酸-3-磷酸合酶（EPSPS）抑制剂以及光系统II抑制剂类除草剂产生多重抗性的可能性。本研究以3个鬼针草属种群为材料，采用剂量反应实验测定其对咪唑乙烟酸（imazethapyr）、氯嘧磺隆（chlorimuron）与双氯磺草胺（diclosulam）的敏感性；同时对采自巴西巴拉那州（PR）及巴西其他区域的34个种群开展敏感性评价。剂量反应实验结果显示，不同种群呈现出多样化的交互抗性模式：1个种群对上述3种除草剂均产生抗性，第2个种群对咪唑乙烟酸和氯嘧磺隆表现出耐受性，但对双氯磺草胺敏感，第3个种群仅对咪唑乙烟酸产生抗性。研究表明，鬼针草属种群间确实存在多样的交互抗性模式，但未观察到采样区域与抗性模式之间存在显著关联。综上，最常见的抗性模式为R2型（即对咪唑乙烟酸、氯嘧磺隆及双氯磺草胺均产生抗性）。