N-demethylation of neonicotinoid insecticide acetamiprid by bacterium Stenotrophomonas maltophilia CGMCC 1.1788

Abstract

Our previous study found that Stenotrophomonas maltophilia CGMCC 1.1788 could hydroxylate imidacloprid (IMI) to 5-hydroxy IMI. Here we first report that S. maltophilia CGMCC 1.1788 can demethylate acetamiprid (AAP) to form IM 2-1 that was characterized by HPLC-MS/MS and NMR. IM 2-1 retained only 10.5% contact activity and 13.1% oral activity of AAP against horsebean aphid. Time course of biotransformation under existing of sucrose revealed that 58.9% of AAP disappeared, but only 16.7% of reduced AAP was transformed to IM 2-1, after 8 days. Both demethylation and degradation of AAP contribute to the weak bioefficacy of AAP in soil application. The differences in metabolism and detoxification pathways between AAP and IMI are probably originated from the structural differences of these insecticides.

Neonicotinoid Metabolism: Compounds, Substituents, Pathways, Enzymes, Organisms, and Relevance

“…Stenotrophomonas maltophilia GGMCCL.1788 hydroxylates IMI in the 5-position 41 and THI in the 4-position 42 and N-demethylates ACE. 43 Pseudomonas sp.1G converts IMI and TMX to their N-nitrosoguanidine, guanidine, and N-carbamoylimine metabolites. 44 Rhodotorula mucilaginosa strain IM-2 converts ACE to the N-acetyl derivative of 6-chloropyridinyl-3-methylamine and hydrolyzes THI to the corresponding Journal of Agricultural and Food Chemistry ARTICLE N-carbamoylimine.…”

Biodegradation of the neonicotinoid insecticide acetamiprid in surface water by the bacterium Variovorax boronicumulans CGMCC 4969 and its enzymatic mechanism

“…20 The bacterium Stenotrophomonas maltophilia CGMCC 1.1788 degraded AAP via N-demethylation to form IM 2-1. 21 In a previous study, we reported that the plant growth-promoting rhizobacterium Variovorax boronicumulans CGMCC 4969 degraded thiacloprid to its amide metabolite and the carcinogen acrylamide to acrylic acid. 22,23 Bacteria belonging to the genus Variovorax are common inhabitants of water and soil.…”

Hydroxylation of thiacloprid by bacterium Stenotrophomonas maltophilia CGMCC1.1788

“…Bioassay showed that the hydroxylation by S. maltophilia and decyanotation of 4-hydroxy thiacloprid are dramatic detoxic process, and the Ndemethylation of acetamiprid is ten times lower detoxicity (Chen et al 2008), while the hydroxylation of imidacloprid and subsequent elimination of water to form olefin imidacloprid are ten times increasing Fig. 4 Inhibition of PBO on the hydroxylation of thiacloprid by resting cells of S. maltophilia.…”

“…The feeding and contact bioassay against horsebean aphid Aphis craccivora was tested by the method described by Nauen (1999) and our previous study (Chen et al 2008) at the National Pesticide Research & Development South Centre, Nanjing. Bioassay was replicated three times, the number of pest exceeded 30 in each dependant experiment, and the total number of pest was more than 100.…”

“…The insecticidal activity of olefin imidacloprid was 19 times higher than that of imidacloprid against horsebean aphid imago (Dai et al 2006). S. maltophilia also transformed acetamiprid to form the 10 times lower insecticidal metabolite, N-demethylated(IM 2-1) (Chen et al 2008). These results lead a new investigation on the microbial transformation to understand why longer time and better control are achieved when imidacloprid is applied as a soil drench application than the other methods, and acetamiprid shows weaker bioefficacy after soil application.…”