Pseudomonas syringae CC1557: A highly virulent strain with an unusually small type iii effector repertoire that includes a novel effector

Kevin L. Hockett, Marc T. Nishimura, Erick Karlsrud, Kevin Dougherty, David A. Baltrus

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Both type III effector proteins and nonribosomal peptide toxins play important roles for Pseudomonas syringae pathogenicity in host plants, but whether and how these pathways interact to promote infection remains unclear. Genomic evidence from one clade of P. syringae suggests a tradeoff between the total number of type III effector proteins and presence of syringomycin, syringopeptin, and syringolin A toxins. Here, we report the complete genome sequence from P. syringae CC1557, which contains the lowest number of known type III effectors to date and has also acquired genes similar to sequences encoding syringomycin pathways from other strains. We demonstrate that this strain is pathogenic on Nicotiana benthamiana and that both the type III secretion system and a new type III effector, hopBJ1, contribute to pathogenicity. We further demonstrate that activity of HopBJ1 is dependent on residues structurally similar to the catalytic site of Escherichia coli CNF1 toxin. Taken together, our results provide additional support for a negative correlation between type III effector repertoires and the potential to produce syringomycin-like toxins while also highlighting how genomic synteny and bioinformatics can be used to identify and characterize novel virulence proteins.

Original languageEnglish (US)
Pages (from-to)923-932
Number of pages10
JournalMolecular Plant-Microbe Interactions
Volume27
Issue number9
DOIs
StatePublished - Sep 2014

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science

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