Neonicotinoid Insecticides: Oxidative Stress in Planta and Metallo-oxidase Inhibition

• Published in: Journal of agricultural and food chemistry 2011-05, Vol.59 (9), p.4860-4867
• Main Authors: Ford, Kevin A, Gulevich, Alexander G, Swenson, Tami L, Casida, John E
• Format: Article
• Language: English
• Subjects: acetamiprid; Biological and medical sciences; catalase; cell death; clothianidin; Crop and Animal Protection Chemistry; dinotefuran; Down-Regulation; Enzyme Inhibitors - pharmacology; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Glycine max; Glycine max - drug effects; Glycine max - enzymology; Glycine max - metabolism; imidacloprid; insect control; insect pests; Insecticides - pharmacology; metabolites; nitenpyram; Nitro Compounds - pharmacology; oxidative stress; Oxidative Stress - drug effects; Oxidoreductases - antagonists & inhibitors; Oxidoreductases - metabolism; plant growth; Plant Proteins - antagonists & inhibitors; Plant Proteins - metabolism; plant response; reactive oxygen species; seedlings; soybeans; stress response; thiacloprid; thiamethoxam; xanthine oxidase
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf200485k

Neonicotinoids not only control insect pests but also sometimes independently alter plant growth and response to stress. We find that imidacloprid, thiacloprid, acetamiprid, thiamethoxam, and clothianidin but not nitenpyram and dinotefuran induce foliar lesions and peroxidative damage in soybean (Glycine max) seedlings assayed with the 3,3′-diaminobenzidine stain. The chloropyridinyl-carboxylic acid (COOH) but not the -carboxaldehyde (CHO) metabolites induce peroxidative damage but in a different pattern. Surprisingly, the chlorothiazolyl -CHO and -COOH metabolites induce chlorosis but no clear superimposable peroxidative damage or cell death. Four metallo-oxidases known to modulate reactive oxygen species were not sensitive in vitro to the parent neonicotinoid itself but were to several CHO and COOH metabolites and related compounds, with a sensitivity order of CHO > COOH and tyrosinase > xanthine oxidase and aldehyde oxidase > catalase. Although metallo-oxidase inhibition does not correlate overall with lesion formation, it may play an as yet unknown role in plant response to neonicotinoids.