山东省小麦田播娘蒿对双氟磺草胺抗性水平及靶标抗性机理

【背景】播娘蒿(Descurainia sophia)是一种冬小麦田分布广泛且危害严重的阔叶杂草,双氟磺草胺则是目前冬小麦田防除阔叶杂草应用面积最大的一种ALS抑制剂类除草剂。双氟磺草胺经多年应用后,对部分区域冬小麦田播娘蒿防治效果下降,可能与当地播娘蒿对双氟磺草胺产生抗药性有关。【目的】明确山东省冬小麦田播娘蒿对双氟磺草胺的抗性水平和抗性机理,为制定小麦田播娘蒿等阔叶杂草精准区域防控提供理论依据。【方法】以播娘蒿为研究对象,在温室内采用整株生物测定法测定40个播娘蒿种群对双氟磺草胺和对比药剂苯磺隆、2甲4氯共3种除草剂的抗性水平,同时根据播娘蒿ALS基因序列,设计引物,提取对双氟磺草胺高抗的播娘蒿单株基因组DNA,测序获得序列与敏感型基因进行比对,查找突变位点,明确靶标抗性机理。【结果】抗性水平测定结果表明,40个播娘蒿种群中有32个对双氟磺草胺敏感,占80.00%,低抗、中抗和高抗种群分别有3、3和2个,JN-1、JNI-2、LY-2为低抗种群,LC-3、LY-4、YT-1为中抗种群,相对抗性指数(RI)分别为49.00、26.44、21.09,BZ-1和DZ-3属于高抗种群,RI...

Resistance Level and Mechanism of Descurainia sophia to Florasulam in Wheat Field of Shandong Province

【Background】 Descurainia sophia is the most widely distributed and harmful broad-leaved weed in winter wheat field, and florasulam is the most widely used ALS inhibitor herbicide for controlling broad-leaved weeds. After several years of application, the control effect of florasulam on D. sophia has been found to decline in some wheat fields, which may be related to the resistance. 【Objective】 The objective of this study is to clarify the resistance level and mechanism of D. sophia to florasulam, and to provide theoretical basis for the establishment of precise regional control of broad-leaved weeds in wheat field. 【Method】 A total of 40 populations of D. sophia were collected from winter wheat fields. Whole-plant dose response experiments were conducted to determine the resistance level of 40 populations to florasulam, tribenuron-methyl and MCPA in the greenhouse. At the same time, according to the ALS gene sequence of D. sophia, the genomic DNA of a single plant with high resistance to florasulam was extracted. The ALS gene sequences were obtained and compared with that of sensitive type Arabidopsis thaliana to find out the mutation site and the resistance mechanism. 【Result】 The results of resistance level determination showed that 32 of the 40 D. sophia populations were sensitive to florasulam, accounting for 80.00%. There were 3, 3 and 2 populations of low resistance, medium resistance and high resistance, respectively. JN-1, JNI-2 and LY-2 belonged to low resistance populations. Three populations LC-3, LY-4 and YT-1 belonged to medium resistance with resistance index (RI) of 49.00, 26.44 and 21.09, respectively. BZ-1 and DZ-3 belonged to high resistance populations with RI of 52.00 and 194.00, respectively. The ALS sequence analysis showed that there were mutations from CCT (pro) to TCT (Ser) or CTT (Leu) in amino acid 197 of ALS gene in BZ-1, while TGG (Trp) to TTG (Leu) in amino acid 574 of ALS gene in DZ-3. In addition, 19 of the 40 D. sophia populations were resistant to tribenuron-methyl, accounting for 47.50%, among them, 11 populations were low resistance, 6 populations were medium resistance with RI of 38.05, 13.55, 11.54, 10.45, 11.50, 11.02, and DZ-3 and LY-4 belonged to high resistance populations with RI of 244.75 and 68.50, respectively. All 40 populations were sensitive to MCPA. 【Conclusion】 Among the 40 populations of D. sophia collected from wheat fields in Shandong Province, 20.00% of them are resistance to florasulam, and the substitutions of amino acids occur in different positions in the populations with high resistance to florasulam. The resistance of D. sophia to tribenuron-methyl is still very serious, but all the populations are not resistant to MCPA. In view of the resistance area of D. sophia, the alternative and mixed use of herbicides with multiple mechanisms should be promoted, which can not only delay and control the development of resistance in weeds, but also expand the weed control spectrum and reduce the use of herbicides.