cyenopyrafen and pyridaben

Cyenopyrafen is a recently developed acaricide with a new mode of action as a complex II inhibitor. However, it was recently shown that cross-resistance to cyenopyrafen can occur in resistant field strains of Tetranychus urticae, which might be linked to the previous use of classical METI acaricides. Here, we selected for cyenopyrafen resistance and studied the molecular mechanisms that underlie resistance.. Selection for cyenopyrafen resistance confers cross-resistance to the complex II inhibitor cyflumetofen, but also to pyridaben, a frequently used complex I inhibitor. Cyenopyrafen resistance is highly synergised by piperonyl butoxide, and a 15-fold higher P450 activity was detected in the resistant strain. Target-site resistance was not detected. Genome-wide gene expression data, followed by a meta-analysis of previously obtained gene expression data, revealed the overexpression specifically of CYP392A11 and CYP392A12.. Cyenopyrafen resistance is strongly linked to the overexpression of two P450s, which probably explains the observed cross-resistance. This information is highly valuable, as the novel complex II inhibitors cyenopyrafen and cyflumetofen are in the process of worldwide registration. The role of both CYP392A11 and CYP392A12 should be further supported by functional expression, but they are very promising candidates as molecular diagnostic markers for monitoring cyenopyrafen susceptibility in the field.

Topics: Acaricides; Acrylonitrile; Animals; Arthropod Proteins; Drug Resistance; Phylogeny; Propionates; Pyrazoles; Pyridazines; Selection, Genetic; Sequence Analysis, DNA; Tetranychidae

Cyenopyrafen is an inhibitor of complex II of the mitochondrial electron transport chain. It has a molecular structure that shares some common features with frequently used complex I inhibitors such as pyridaben. To evaluate whether this similarity in structure poses a cross-resistance risk that might complicate resistance management, we selected for pyridaben and cyenopyrafen resistance in the laboratory and characterized resistance.. The selection for cyenopyrafen conferred cross-resistance to pyridaben and vice versa. Resistance towards these both acaricides was incompletely dominant in adult females. However, in eggs maternal effects were observed in pyridaben resistance, but not in the cyenopyrafen-resistance (completely dominant). In the cyenopyrafen resistant strain, the LC50 of eggs remained lower than the commercially recommended concentration. The common detoxification mechanisms by cytochrome P450 was involved in resistance to these acaricides. Carboxyl esterases were also involved in cyenopyrafen resistance as a major factor.. Although cross-resistance suggests that pyridaben resistance would confer cyenopyrafen cross-resistance, susceptibility in eggs functions to delay the development of cyenopyrafen resistance.

Topics: Acaricides; Acrylonitrile; Animals; Cytochrome P-450 Enzyme System; Drug Resistance; Female; Male; Ovum; Pyrazoles; Pyridazines; Tetranychidae; Tick Control