title: Functional analysis of genes involved in the synthesis of syringolin A by Pseudomonas syringae pv. syringae B301 D-R.
abstract: Strains of the phytopathogenic bacterium Pseudomonas syringae pv. syringae secrete a family of structurally closely related peptide derivatives dubbed syringolins, of which syringolin A is the major variant. The function of syringolins in the interaction of P. syringae pv. syringae with their host plants presently is unknown. It is hypothesized that they may constitute virulence factors. However, syringolins are determinants recognized and reacted to by nonhost plant species, and syringolin A has been shown to induce hypersensitive death of cells colonized by powdery mildew in wheat and, thus, to reprogram a compatible interaction into an incompatible one. Syringolin A is an unusual derivative of a tripeptide that contains a 12-membered ring consisting of the amino acids 5-methyl-4-amino-2-hexenoic acid and 3,4-dehydrolysine, two nonproteinogenic amino acids. Here we report the cloning, sequencing, and analysis of genes involved in the biosynthesis of syringolin A. The genes encode proteins consisting of modules typical for nonribosomal peptide synthetases and type I polyketide synthetases, as well as proteins likely involved in the transcriptional regulation of syringolin A biosynthesis and in syringolin A export. The structure and arrangement of the modules lead to the formulation of a model explaining the synthesis of the tripeptide, including the formation of the two nonproteinogenic amino acids in the ring structure of syringolin A.
authors.affiliation: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
authors.forename: Hans
authors.initials: H
authors.lastname: Amrein
authors.forename: Stefan
authors.initials: S
authors.lastname: Makart
authors.forename: José
authors.initials: J
authors.lastname: Granado
authors.forename: Roshani
authors.initials: R
authors.lastname: Shakya
authors.forename: Jana
authors.initials: J
authors.lastname: Schneider-Pokorny
authors.forename: Robert
authors.initials: R
authors.lastname: Dudler
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000235:genetics* / Q000378:metabolism; D008074:Lipoproteins / Q000096:biosynthesis; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D010456:Peptides, Cyclic / Q000096:biosynthesis* / Q000737:chemistry; D044224:Pseudomonas syringae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D009097:Multienzyme Complexes; D010456:Peptides, Cyclic; D015534:Trans-Activators; C407267:syringolin A; C402636:syringopeptin 22; C032677:syringomycin; D044943:Fatty Acid Desaturases; D010453:Peptide Synthases