Isolation and characterization of non-pathogenic and reduced virulence mutants of Pseudomonas syringae pv. phaseolicola induced by Tn5 transposon insertions

G. Somlyai, Mária Hevesi, Zsófia Bánfalvi, Z. Klement, Kondorosi

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The suicide plasmid pSUP1011 was shown to induce random Tn5 mutations in Pseudomonas syringae pv. phaseolicola. Approximately 1·3% of the transconjugants carrying Tn5 were auxotrophs. The majority of the auxotrophs were unable to cause disease symptoms in susceptible bean pods (Path phenotype) and some of these Path mutants were unable to induce a hypersensitive reaction (HR) in non-host tobacco leaves (HRi mutants), indicating that the nutritional status of the bacterium in the plant influences the induction of pathogenic reactions. Six of the prototrophic Tn5-carrying derivatives (0·3% of the total) were HRi. Genetic and hybridization analysis revealed that the mutants carried the mutations in different genes. Four of the HRi mutants were also Path, while the other two incited mild symptoms in susceptible plants (Vir mutants). The multiplication of the 6 HRi mutants in the intercellular spaces of susceptible plant leaves was drastically reduced compared to that of the wild type strain suggesting that high cell densities are required for the full induction of a pathogenic reaction. Although the biochemical lesions caused by these mutants are not yet characterized, these results indicate that numerous genes are involved in the ability of the bacterium to induce disease symptoms.

Original languageEnglish
Pages (from-to)369-380
Number of pages12
JournalPhysiological and Molecular Plant Pathology
Volume29
Issue number3
DOIs
Publication statusPublished - Jan 1 1986

Keywords

  • chloramphenicol resistant/sensitive
  • Cm/Cm
  • fully pathogenic/non-pathogenic
  • HR
  • HRi/HRi
  • hypersensitive reaction
  • inducer/non-inducer of a HR
  • kanamycin resistant/sensitive
  • Km/Km
  • Path/Path
  • reduced virulence
  • Sm/Sm
  • streptomycin resistant/sensitive
  • Vir

ASJC Scopus subject areas

  • Genetics
  • Plant Science

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