New Pseudomonas spp. Are Pathogenic to Citrus

PLoS One. 2016 Feb 26;11(2):e0148796. doi: 10.1371/journal.pone.0148796. eCollection 2016.


Five putative novel Pseudomonas species shown to be pathogenic to citrus have been characterized in a screening of 126 Pseudomonas strains isolated from diseased citrus leaves and stems in northern Iran. The 126 strains were studied using a polyphasic approach that included phenotypic characterizations and phylogenetic multilocus sequence analysis. The pathogenicity of these strains against 3 cultivars of citrus is demonstrated in greenhouse and field studies. The strains were initially grouped phenotypically and by their partial rpoD gene sequences into 11 coherent groups in the Pseudomonas fluorescens phylogenetic lineage. Fifty-three strains that are representatives of the 11 groups were selected and analyzed by partial sequencing of their 16S rRNA and gyrB genes. The individual and concatenated partial sequences of the three genes were used to construct the corresponding phylogenetic trees. The majority of the strains were identified at the species level: P. lurida (5 strains), P. monteilii (2 strains), P. moraviensis (1 strain), P. orientalis (16 strains), P. simiae (7 strains), P. syringae (46 strains, distributed phylogenetically in at least 5 pathovars), and P. viridiflava (2 strains). This is the first report of pathogenicity on citrus of P. orientalis, P. simiae, P. lurida, P. moraviensis and P. monteilii strains. The remaining 47 strains that could not be identified at the species level are considered representatives of at least 5 putative novel Pseudomonas species that are not yet described.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Citrus / microbiology*
  • Genes, Bacterial
  • Iran
  • Multilocus Sequence Typing
  • Phylogeny
  • Plant Diseases / microbiology*
  • Pseudomonas / classification
  • Pseudomonas / genetics
  • Pseudomonas / pathogenicity*
  • Sigma Factor / genetics
  • Species Specificity
  • Virulence


  • Bacterial Proteins
  • Sigma Factor

Grants and funding

The work was supported by BOS2011 CGL24318 and Consolider CSD2009-00006 from Spanish Ministry of Economy and Competitiveness - MINECO.