Cytochrome P450 BsCYP99A44 and BsCYP704A177 Confer Metabolic Resistance to ALS Herbicides in Beckmannia syzigachne .

is a noxious grassy weed that infests wheat fields in China. Previously, we identified that mesosulfuron-methyl resistance in a population (R, SD04) was conferred by non-target resistance, such as cytochrome P450 mixed-function oxidases (P450s)-based metabolism. RNA sequencing and real-time PCR (qRT-PCR) were used to discover potential P450s-resistant-related genes. Five cytochrome P450s (, , , and ) were found to be highly expressed in R plants. In this study, and were cloned from and transferred into to test the sensitivity of with and without P450s genes to mesosulfuron-methyl and other acetolactate synthase (ALS)-inhibiting herbicides. Transgenic overexpressing became resistant to the sulfonylurea herbicide mesosulfuron-methyl, but showed no resistance to pyroxsulam, imazethapyr, flucarbazone, and bispyribac-sodium. Notably, those overexpressing showed resistance to pyroxsulam and bispyribac-sodium, but not to mesosulfuron-methyl, imazethapyr, and flucarbazone. These results indicated that and transgenic displayed different cross-resistance patterns to ALS-inhibiting herbicides. Subcellular localization revealed that and protein were located in the endoplasmic reticulum. Furthermore, these results clearly indicated that -mediated mesosulfuron-methyl resistance in and may be involved in cross-resistance to pyroxsulam and bispyribac-sodium.