A nonribosomal peptide synthetase gene (mgoA) of Pseudomonas syringae pv. syringae is involved in mangotoxin biosynthesis and is required for full virulence.
Pseudomonas syringae pv. syringae, which causes the bacterial apical necrosis of mango, produces the antimetabolite mangotoxin. We report here the cloning, sequencing, and identity analysis of a chromosomal region of 11.1 kb from strain P syringae pv. syringae UMAF0158, which is involved in mangotoxin biosynthesis. This chromosomal region contains six complete open reading frames (ORFs), including a large gene (ORF5) with a modular architecture characteristic of nonribosomal peptide synthetases (NRPS) named mgoA. A Tn5 mutant disrupted in mgoA was defective in mangotoxin production, revealing the involvement of the putative NRPS gene in the biosynthesis of mangotoxin. This derivative strain impaired in mangotoxin production also showed a reduction in virulence as measured by necrotic symptoms on tomato leaflets. Mangotoxin production and virulence were restored fully in the NRPS mutant by complementation with plasmid pCG2-6, which contains an 11,103-bp chromosomal region cloned from the wild-type strain P syringae pv. syringae UMAF0158 that includes the putative NPRS gene (mgoA). The results demonstrate that mgoA has a role in the virulence of P. syringae pv. syringae. The involvement of an NRPS in the production of an antimetabolite toxin from P. syringae inhibiting ornithine acetyltransferase activity is proposed.
Arrebola
Eva
E
Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.
Cazorla
Francisco M
FM
Romero
Diego
D
Pérez-García
Alejandro
A
de Vicente
Antonio
A
D000123:Acetyltransferases / Q000037:antagonists & inhibitors; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D015139:Blotting, Southern; D002876:Chromosomes, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D023061:Gene Order; D005816:Genetic Complementation Test; D018551:Solanum lycopersicum / Q000382:microbiology; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D018515:Plant Leaves / Q000382:microbiology; D044224:Pseudomonas syringae / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D000123:Acetyltransferases; C020646:glutamate acetyltransferase; D010453:Peptide Synthases