Cytochrome P450‐mediated herbicide metabolism in plants: current understanding and prospects

Abstract

Cytochrome P450s (P450s) have been at the center of herbicide metabolism research as a result of their ability to endow selectivity in crops and resistance in weeds. In the last 20 years, ≈30 P450s from diverse plant species have been revealed to possess herbicide-metabolizing function, some of which were demonstrated to play a key role in plant herbicide sensitivity. Recent research even demonstrated that some P450s from crops and weeds metabolize numerous herbicides from various chemical backbones, which highlights the importance of P450s in the current agricultural systems. However, due to the enormous number of plant P450s and the complexity of their function, expression and regulation, it remains a challenge to fully explore the potential of P450-mediated herbicide metabolism in crop improvement and herbicide resistance mitigation. Differences in the substrate specificity of each herbicide-metabolizing P450 are now evident. Comparisons of the substrate specificity and protein structures of P450s will be beneficial for the discovery of selective herbicides and may lead to the development of crops with higher herbicide tolerance by transgenics or genome-editing technologies. Furthermore, the knowledge will help design sound management strategies for weed resistance including the prediction of cross-resistance patterns. Overcoming the ambiguity of P450 function in plant xenobiotic pathways will unlock the full potential of this enzyme family in advancing global agriculture and food security.

Plant cytochrome P450 plasticity and evolution

“…A similar dual functionality has been observed for promiscuous monoterpenol metabolizing CYP76s that confer a tolerance to another class of herbicides, the phenylureas (H€ ofer et al, 2014). In this light, it is striking that members of the CYP81A subfamily have been recently shown to metabolize a broad range of herbicides, thereby conferring herbicide resistance to monocotyledonous weeds (Dimaano and Iwakami, 2020;Han et al, 2020), while CYP81As from maize were demonstrated to catalyze diverse oxidation reactions on acidic sesquiterpenes to form zealexin antibiotics (Ding et al, 2020).…”

Resistance to a nonselective 4‐hydroxyphenylpyruvate dioxygenase‐inhibiting herbicide via novel reduction–dehydration–glutathione conjugation in Amaranthus tuberculatus

“…Plant P450 proteins are encoded by large, diverse multigene families consisting of c . 350 genes in rice and 250 genes in Arabidopsis , and are involved in numerous processes such as secondary product biosynthesis, fatty acid metabolism, hormone homeostasis and xenobiotic detoxification (Nelson et al ., 2004; Paquette et al ., 2009; Mizutani & Ohta, 2010; Schuler, 2015; Dimaano & Iwakami, 2021). Phase II metabolic reactions are catalyzed by glutathione S ‐transferases (GSTs; EC 2.5.1.18) and uridine diphosphate‐dependent glycosyltransferases, forming GSH conjugates and glucose conjugates, respectively.…”

Investigation of clomazone‐tolerance mechanism in a long‐grain cultivar of rice

“…There are four CYP81A genes annotated in the whole genome of rice, and one of them ( CYP81A6 ) plays a key role in the tolerance of rice to multiple herbicides, such as sulfonylureas and bentazone 12 . The CYP81A P450s often metabolize a variety of herbicides, although some only metabolize a small number or no herbicides 13 . Thus, we hypothesized that the CYP81A genes in rice may explain the differential clomazone sensitivity between short/medium‐ and long‐grain cultivars.…”