Polyphosphate kinase is essential for swarming motility, tolerance to environmental stresses, and virulence in Pseudomonas syringae pv. tabaci 6605

Md Mijan Hossain, Chiharu Tani, Tomoko Suzuki, Fumiko Taguchi, Tatsuhiro Ezawa, Yuki Ichinose

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Polyphosphate kinase (PPK), encoded by the ppk gene, is a principal enzyme responsible for synthesis of inorganic polyphosphate (poly P) from ATP in many Gram-negative bacteria. In order to elucidate the functions of poly P in Pseudomonas syringae pv. tabaci 6605, an in-frame deletion mutant of the ppk gene ({up triangle, open}ppk) was constructed. The {up triangle, open}ppk mutant did not accumulate poly P, whereas the wild-type strain accumulated a large quantity. The mutant had reduced swarming motility, even though it retains swimming motility like the parental strain. The mutant exhibited increased sensitivity to prolonged incubation and environmental stresses, such as heat shock and oxidative stress and reduced exopolysaccharide (EPS) production compared to the wild-type. Northern blot analysis revealed that expression of the rpoS gene, encoding the stationary phase sigma factor RpoS, was reduced in {up triangle, open}ppk in the logarithmic phase, indicating that rpoS is regulated by the ppk gene. The poly P deficient mutant had significantly reduced ability to cause disease in its host tobacco plant and in planta growth of the mutant was also significantly reduced in host tobacco leaves as compared to the wild-type strain. Thus, our results suggest that poly P plays an important role in the virulence of P. syringae pv. tabaci 6605.

Original languageEnglish
Pages (from-to)122-127
Number of pages6
JournalPhysiological and Molecular Plant Pathology
Volume72
Issue number4-6
DOIs
Publication statusPublished - Jul 1 2008

Keywords

  • Environmental stress
  • Polyphosphate kinase
  • Pseudomonas syringae pv. tabaci 6605
  • Tolerance
  • ppk

ASJC Scopus subject areas

  • Genetics
  • Plant Science

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