title: Effects of pesticides on the bacterial production of pyrrolnitrin.
abstract: Pyrrolnitrin is a halogenated bacterial metabolite with antifungal and antibacterial activities which served as a lead structure of synthetic fungicides. Several pyrrolnitrin-producing bacteria are considered to be promising biopesticides. However, the application of these microorganisms is not straightforward since many synthetic pesticides usually coexist in agricultural fields and inevitably affect the efficacy of biocontrol agents. In this regard, effects of 25 xenobiotics, including 18 pesticides, were investigated for pyrrolnitrin biosynthesis by Burkholderia sp. O33 and Pseudomonas fluorescens Pf-5. Strong inhibition of pyrrolnitrin synthesis was observed in 9 chemicals, including 6 pesticides, while glyphosate and validamycin enhance biosynthesis. Fenpiclonil and fludioxonil strongly inhibit the oxidative transformation of aminopyrrolnitrin to pyrrolnitrin. Halogenation reaction to aminopyrrolnitrin was reduced by methimazole, a well-known flavin-dependent monooxygenase inhibitor. Most pesticides gave moderate growth inhibitory effects. The results suggested that synthetic chemicals can modulate the efficacy of pyrrolnitrin producing bacteria, through the inhibition of cell growth or pyrrolnitrin biosynthesis. Pathway specific inhibition by fenpiclonil, fludioxonil, and methimazole will give structural insights of corresponding enzymes.
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Keum
authors.forename: Hye Ri
authors.initials: HR
authors.lastname: Lee
authors.forename: Jeong-Han
authors.initials: JH
authors.lastname: Kim
mesh_terms: D019117:Burkholderia / Q000187:drug effects* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D010575:Pesticides / Q000494:pharmacology*; D011551:Pseudomonas fluorescens / Q000187:drug effects* / Q000378:metabolism; D011764:Pyrrolnitrin / Q000096:biosynthesis*
chemical_list: D010575:Pesticides; D011764:Pyrrolnitrin