Cytochrome P450 CYP81A104 in Eleusine indica confers resistance to multiherbicide with different modes of action.

Background: Developing herbicide-resistant (HR) crop cultivars is an efficient way to control weeds and minimize crop yield losses. However, widespread and long-term herbicide application has led to the evolution of resistant weeds. Here, we established a resistant (R) E. indica population, collected from imidazolinone-resistant rice cultivar fields.

Results: The R population evolved 4.5-fold resistance to imazamox. Acetolactate synthase (ALS) gene sequencing and ALS activity assays excluded the effect of target-site resistance in this population. P450 inhibitor malathion pretreatment significantly reversed resistance to imazamox. RNA sequencing showed that a P450 gene CYP81A104 was expressed higher in R versus susceptible (S) plants. Arabidopsis overexpressing CYP81A104 showed resistance to ALS inhibitors (imazamox, tribenuron-methyl, penoxsulam and flucarbazone-sodium), PSII inhibitor (bentazone), hydroxyphenyl pyruvate dioxygenase inhibitor (mesotrione) and auxin mimics (MCPA), which was generally consistent with the results presented in the R population.

Conclusion: This study confirmed that the CYP81A104 gene endowed resistance to multiherbicides with different modes-of-action. Our findings provide an insight into the molecular characteristics of resistance and contribute to formulating an appropriate strategy for weed management in HR crops. © 2024 Society of Chemical Industry.