Molecular Basis of Resistance to Bensulfuron-Methyl in a Smallflower Umbrella Sedge (Cyperus difformis L.) Population from China

Smallflower umbrella sedge (Cyperus difformis L.) is an invasive weed, and infestations of C. are increasing in rice (Oryza sativa fields China. Bensulfuron-methyl a widely used sulfonylurea herbicide that inhibits the acetolactate synthase (ALS) enzyme has been recent years for effectively controlling annual weeds Cyperaceae family. In this study, suspected resistant population (BBHY1) was collected from field Huaiyuan County, Anhui Province, China, survived treatment with bensulfuron-methyl at field-recommended rate (FRR). Single-dose tests whole-plant bioassays confirmed BBHY1 to had evolved high level resistance, resistance index (RI) 12.87. Sequencing ALS gene revealed CCT CAT point mutation codon 197, which caused P-to-H substitution plants. Analysis relative expression no significant differences between susceptible populations. Inhibiting activity cytochrome P450s (P450s) or glutathione S-transferases (GSTs) effect on resistance. The exhibited cross-resistance pyrazosulfuron-ethyl, penoxsulam, bispyribac-sodium, RIs ranging 5.48 20.63, but remained MCPA sodium, florpyrauxifen-benzyl, bentazon, <1.00. These herbicides could be potentially as alternatives populations managing other aggressive fields.