Resistance of Eleusine indica to acetyl-CoA carboxylase-inhibiting herbicides in direct-seeded rice and its molecular mechanism

The objectives of this study were to illuminate the sensitivity of Eleusine indica population in rice field of direct seeding to acetyl-CoA carboxylase (ACCase)-inhibiting herbicides and reveal its molecular resistance mechanism. Whole-plant bioassay showed that the population SJ-1 was highly resistant to metamifop, cyhalofop-butyl, fenoxaprop-p-ethyl, haloxyfop-R-methyl and sethoxydim, with resistance indexes of 56.6, 62.5, 128, 52.0 and 16.3, respectively. And it was slightly resistant to clethodim, with a resistance index of 4.86. By comparing the partial ACCase sequences derived from the resistant and susceptible populations, the SJ-1 population was found to contain one amino acid substitution of aspartate (GAT) for glycine (GGT) at the codon position 2078. This mutation in the ACCase gene might be responsible for the resistance to ACCase-inhibiting herbicides in the resistant population of E. indica.