A Similar Metabolism of Chlorotoluron in Cell Suspension Cultures from Near-Isogenic Susceptible and Tolerant Lines of Wheat

The metabolism of the herbicide chlorotoluron was followed in cell suspension cultures of wheat. The cultures originated from plants of the susceptible variety Corin, the tolerant variety Clément, and six near-isogenic lines, 9S, 10S, 16S, 17T, 18T, and 24T [susceptible (S) and tolerant (T), respectively]. The six lines had the genetic background of the susceptible variety Chinese Spring, but the three lines 17T, 18T, and 24T contained a gene for tolerance (Sul) transferred from the variety Cappelle-Desprez. The cultures from Corin and Clément produced identical patterns of metabolites which were also identical to those found in plants. The rate of metabolism of the herbicide was slightly higher in the cell culture of Clément (T) than in Corin (S), as reported for the corresponding plants. Patterns of metabolites were similar in the cell cultures from the six isogenic lines. The rate of metabolism was the same in 9S, 10S, 16S, 18T, and 24T, and lower in 17T, so that a differential rate of metabolism was not found between T and S cell cultures. The occurrence of a differential rate of metabolism as the primary mechanism of varietal selectivity of wheat to chlorotoluron is discussed.