Expression and comparison of sweet corn CYP81A9s in relation to nicosulfuron sensitivity

Eunsoo Choe, Martin M. Williams

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Nicosulfuron, a sulfonylurea herbicide widely used for grass weed control in corn production, injures some sweet corn hybrids and inbreds. A specific cytochrome P450 (P450), CYP81A9, is suggested to be responsible for sensitivity to nicosulfuron and other P450-metabolized herbicides. Corn CYP81A9 enzymes were expressed in E. coli and investigated to find the factor(s) associated with their function and variation in metabolizing nicosulfuron. RESULT: Recombinant expressed CYP81A9s from tolerant sweet corn inbreds produced an active form of P450, while CYP81A9 from a sensitive inbred produced an inactive form. Nicosulfuron bound to tolerant CYP81A9s, and produced reverse-type I ligand, while sensitive CYP81A9 showed no interaction with nicosulfuron. Investigation of 106 sweet corn inbreds showed variation in nicosulfuron injury. A survey of sweet corn CYP81A9 sequences showed mutations in codons for amino acids at 269, 284, 375, and 477 occurred in sweet corn inbreds with complete loss of P450 function (with mean injury >91%) and amino acid changes at 208 and 472 occurred in inbreds with moderate and complete loss of P450 function (with mean injury >14%). CONCLUSION: Our results support that CYP81A9 enzyme is responsible for metabolizing nicosulfuron in sweet corn, and different types of amino acid changes in CYP81A9 sequence are associated with variation in nicosulfuron injury. Therefore, a careful selection of the tolerant allele will be critical for improving tolerance to nicosulfuron and several other P450-metabolized herbicides.

Original languageEnglish (US)
Pages (from-to)3012-3019
Number of pages8
JournalPest Management Science
Issue number9
StatePublished - Sep 1 2020
Externally publishedYes


  • CYP81A9
  • P450-metabolized herbicide
  • Zea mays
  • cytochrome P450
  • nicosulfuron herbicide
  • nsf1

ASJC Scopus subject areas

  • Insect Science
  • Agronomy and Crop Science


Dive into the research topics of 'Expression and comparison of sweet corn CYP81A9s in relation to nicosulfuron sensitivity'. Together they form a unique fingerprint.

Cite this