A Physical Map of the Syringomycin and Syringopeptin Gene Clusters Localized to an Approximately 145-kb DNA Region of Pseudomonas syringae pv. syringae Strain B301D

Autor: Brenda K. Scholz-Schroeder, Jonathan D. Soule, Shi-En Lu, Ingeborg Grgurina, Dennis C. Gross
Jazyk: angličtina
Rok vydání: 2001
Předmět:
Zdroj: Molecular Plant-Microbe Interactions, Vol 14, Iss 12, Pp 1426-1435 (2001)
Druh dokumentu: article
ISSN: 1943-7706
0894-0282
DOI: 10.1094/MPMI.2001.14.12.1426
Popis: Genetic and phenotypic mapping of an approximately 145-kb DraI fragment of Pseudomonas syringae pv. syringae strain B301D determined that the syringomycin (syr) and syringopeptin (syp) gene clusters are localized to this fragment. The syr and syp gene clusters encompass approximately 55 kb and approximately 80 kb, respectively. Both phytotoxins are synthesized by a thiotemplate mechanism of biosynthesis, requiring large multienzymatic proteins called peptide synthetases. Genes encoding peptide synthetases were identified within the syr and syp gene clusters, accounting for 90% of the DraI fragment. In addition, genes encoding regulatory and secretion proteins were localized to the DraI fragment. In particular, the salA gene, encoding a regulatory element responsible for syringomycin production and lesion formation in P. syringae pv. syringae strain B728a, was localized to the syr gene cluster. A putative ATP-binding cassette (ABC) transporter homolog was determined to be physically located in the syp gene cluster, but phenotypically affects production of both phytotoxins. Preliminary size estimates of the syr and syp gene clusters indicate that they represent two of the largest nonribosomal peptide synthetase gene clusters. Together, the syr and syp gene clusters encompass approximately 135 kb of DNA and may represent a genomic island in P. syringae pv. syringae that contributes to virulence in plant hosts.
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