title: Indole-3-Acetic Acid Produced by Burkholderia heleia Acts as a Phenylacetic Acid Antagonist to Disrupt Tropolone Biosynthesis in Burkholderia plantarii.
abstract: Burkholderia heleia PAK1-2 is a potent biocontrol agent isolated from rice rhizosphere, as it prevents bacterial rice seedling blight disease caused by Burkholderia plantarii. Here, we isolated a non-antibacterial metabolite from the culture fluid of B. heleia PAK1-2 that was able to suppress B. plantarii virulence and subsequently identified as indole-3-acetic acid (IAA). IAA suppressed the production of tropolone in B. plantarii in a dose-dependent manner without any antibacterial and quorum quenching activity, suggesting that IAA inhibited steps of tropolone biosynthesis. Consistent with this, supplementing cultures of B. plantarii with either L-[ring-(2)H5]phenylalanine or [ring-(2)H2~5]phenylacetic acid revealed that phenylacetic acid (PAA), which is the dominant metabolite during the early growth stage, is a direct precursor of tropolone. Exposure of B. plantarii to IAA suppressed production of both PAA and tropolone. These data particularly showed that IAA produced by B. heleia PAK1-2 disrupts tropolone production during bioconversion of PAA to tropolone via the ring-rearrangement on the phenyl group of the precursor to attenuate the virulence of B. plantarii. B. heleia PAK1-2 is thus likely a microbial community coordinating bacterium in rhizosphere ecosystems, which never eliminates phytopathogens but only represses production of phytotoxins or bacteriocidal substances.
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.|Institute of Pesticide and Environmental Toxicology, Zhejiang University, No. 268 Kaixuan Road, Hangzhou 310029, China.
authors.forename: Mengcen
authors.initials: M
authors.lastname: Wang
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Tachibana
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.|Frontier Research Center for Post-Genome Science and Technology, Faculty of Advanced Life Sciences, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Murai
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
authors.forename: Sharon Yu Ling
authors.initials: SY
authors.lastname: Lau
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, No. 268 Kaixuan Road, Hangzhou 310029, China.
authors.forename: Mengchao
authors.initials: M
authors.lastname: Cao
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, No. 268 Kaixuan Road, Hangzhou 310029, China.
authors.forename: Guonian
authors.initials: G
authors.lastname: Zhu
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hashimoto
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Hashidoko
mesh_terms: D019117:Burkholderia / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D010648:Phenylacetates / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D014334:Tropolone / Q000378:metabolism*
chemical_list: D007210:Indoleacetic Acids; D010648:Phenylacetates; C030737:indoleacetic acid; D014334:Tropolone; C025136:phenylacetic acid