Molecular Basis of Resistance to Mesosulfuron-Methyl in a Black-Grass (Alopecurus myosuroides Huds.) Population from China

Black-grass (Alopecurus myosuroides Huds.) is a common weed in Chinese wheat fields, and has become troublesome due to its evolution of herbicide resistance. One black-grass population (HN-14) collected from field where herbicides were applied was suspected be resistant (R) mesosulfuron-methyl. This study aims establish cross-resistance pattern explore potential resistance mechanisms. The results whole-plant dose response assay showed that the had high mesosulfuron-methyl (33-fold); meanwhile, no synergism P450s activity inhibitor malathion observed. sequencing revealed ALS mutation Trp-574-Leu occurred R plants. vitro enzyme assays also supported extractable plants 23.22-fold In light “R” rating system, HN-14 evolved RRR RR fenoxaprop-P-ethyl, clodinafop-propargyl, haloxyfop-methyl, fluazifop-P-butyl R? (resistance may developing) pinoxaden, however remains sensitive imazethapyr, quizalofop-P-ethyl, tralkoxydim, isoproturon. These indicated driven by target-site mechanism rather than nontarget (at least P450s-mediated) mechanism.