Carbendazim Resistance of <i>Fusarium graminearum</i> From Henan Wheat

Abstract

Fusarium head blight, also called scab, is caused by <i>Fusarium graminearum</i> and is one of the most important destructive diseases of wheat. The frequency of carbendazim resistance in 1,132 isolates of <i>F. graminearum</i> recovered from fields in different regions of Henan Province in 2016, 2017, and 2018 was determined. A total of 31 <i>F. graminearum</i> isolates resistant to carbendazim were detected, including 30 moderately resistant isolates and one highly resistant isolate. The frequency of resistance of <i>F. graminearum</i> isolates to carbendazim was 2.7%. The range of effective concentration (EC₅₀) values of 1,101 sensitive isolates and 30 moderately resistant isolates was 0.08 to 0.98 μg ml^-1 and 2.73 to 13.28 μg ml^-1, respectively. The mean ± SD EC₅₀ value was 0.55 ± 0.13 μg ml^-1 and 5.61 ± 2.58 μg ml^-1, respectively. The EC₅₀ value of the highly resistant isolate was 21.12 μg ml^-1. Point mutation types of the carbendazim-resistant isolates were characterized by cloning the β₂-tubulin gene of 31 resistant isolates. Three point mutation types at amino acids F167Y, E198Q, and E198L in the β₂-tubulin gene of resistant isolates were identified. Among 31 resistant isolates, the frequency of point mutation types in F167Y, E198Q, and E198L of the β₂-tubulin gene was 71.0, 25.8, and 3.2%, respectively. The data indicate that <i>F. graminearum</i> has developed resistance to carbendazim in Henan Province, and single point mutations at amino acid F167Y were the predominant type of mutation detected.