靶标基因突变导致入侵性杂草长芒苋对咪唑乙烟酸产生抗性

长芒苋Amaranthus palmeri生长迅速,适应性广,繁殖系数高,具有很强的竞争性,已在我国多地定植,对作物产量及生态环境构成潜在威胁.一旦其对除草剂产生抗性,将大大增加治理难度.本试验研究了采自不同地点的长芒苋种群对除草剂咪唑乙烟酸的抗性水平和抗性机理.整株生物测定得出,长芒苋疑似抗性种群和敏感种群对咪唑乙烟...

Target site mutation in the ALS gene endowing imazethapyr resistance in invasive weed Amaranthus palmeri in China

Palmer amaranth Amaranthus palmeri, an alien invasive species, has colonized in many sites all across China. It has rapid growing speed, wide adaptability and high reproduction coefficient with strong competitiveness, which poses a potential threat to crop yield and ecological environment. Once endowing resistance to herbicide, it will be more difficult for the weed control. The objective of this study was to determine whether A.palmeri populations collected from the two sites of China was imazethapyr resistant and to reveal the resistant mechanism to the herbicide. Results of whole plant dose response experiments showed that the RI of the suspected resistant population was found to be 339.78 fold more resistant to imazethapyr than a susceptible population based on biomass reduction (GR50 values of 6 584.18 g/hm2 and 19.38 g/hm2 in suspected resistant population and the susceptible population, respectively). The ALS gene sequence analysis showed that in the suspected resistant populations, an amino acid substitution of position 574 (Trp-574-Leu) in some resistant plants and position 653 (Ser-653-Asp) in other resistant plants. Additionally, double mutation (both Trp-574-Leu and Ser-653-Asp) accounted for 35% in all tested plants. This research confirms that high level resistance of A. palmeri to ALS inhibiting herbicide imazethapyr with Trp574 to Leu and Ser653 to Asp amino acid substitution is the most likely mode of resistance. It is for the first report that A.palmeri population evolved target resistance to imazethapyr in China, and the resistance of invasive weeds to herbicides also posed a new challenge to the management of invasive weeds.