CYTOCHROME P450 CYP72A219 IS INVOLVED IN EVOLUTION OF METABOLIC RESISTANCE TO TEMBOTRIONE IN Amaranthus palmeri POPULATIONS

Evolution of metabolic herbicide resistance is a major issue for weed management. Few genes and regulatory mechanisms have been identified, particularly in dicotyledonous weed species. We identified putative causal genes and regulatory mechanism for tembotrione-resistance in Amaranthus palmeri. Cytochrome P450 candidate genes were identified through RNA-seq analysis. We validated their functions using heterologous expression in S. cerevisae. Promoters of the candidate P450 genes were analyzed. We performed QTL mapping to identify genomic regions associated with resistance. CYP72A1182 deactivated tembotrione. This gene had increased expression in other A. palmeri populations resistant to multiple herbicides, including tembotrione. Resistant plants exhibited polymorphisms in the promoter of CYP72A1182. We identified QTLs linked to herbicide resistance, including one on chromosome 4 approximately 3 Mb away from CYP72A1182. CYP72A1182 is involved in tembotrione resistance in A. palmeri. Increased expression of this gene could be due to cis-regulation in the promoter, as well as trans-regulation from transcription factors. Further studies are in progress to test this hypothesis. The elucidation of regulatory genes is crucial for developing innovative weed management approaches and target-based novel molecules. HIGHLIGHTSOur study identifies that the CYP72A1182 gene has a functional role in metabolic herbicide resistance in Amaranthus palmeri and is linked to cis-regulatory polymorphisms, advancing metabolic resistance understanding in dicots.