The operon for cytokinin biosynthesis of Erwinia herbicola pv. gypsophilae contains two promoters and is plant induced

Ming Guo, Shulamit Manulis, Isaac Barash, Amnon Lichter

Research output: Contribution to journalArticlepeer-review

Abstract

The operon for cytokinin biosynthesis in the gall-forming bacterium Erwinia herbicola pv. gypsophilae (Ehg) has been previously shown to reside on an indigenous plasmid (pPATHEhg) that is mandatory for pathogenicity. This operon consists of two genes: the first open reading frame (pre-etz) is of unknown function, whereas the second one (etz) encodes for isopentenyl transferase. Northern hybridization performed with the wild-type strain Ehg824-1 grown in Luria-Bertani broth demonstrated two transcripts of which an etz-specific transcript (1.0 kb) was predominant. Fusion of upstream DNA fragments of both pre-etz and etz to the ice nucleation reporter gene inaZ in pVSP61 showed high ice nucleation activity in both cultures, confirming the presence of two independent promoters. An increase of 1-1.5 orders in transcriptional activity of these promoters was observed following inoculation of gypsophila cuttings. Mutants of Ehg824-1 were generated by insertion of inaZ into pre-etz and etz using the transposon reporter Tn3-Spice. An increase of about two orders in transcriptional activity was recorded with both mutants following inoculation of gypsophila or bean cuttings. A similar induction was also observed when the bacteria were applied to the leaf surface of these plants. Unlike other virulence genes present on the pPATHEhg, neither pre-etz nor etz was regulated by the adjacent hrp gene cluster.

Original languageEnglish
Pages (from-to)1126-1131
Number of pages6
JournalCanadian Journal of Microbiology
Volume47
Issue number12
DOIs
StatePublished - 2001

Keywords

  • Cytokinin
  • Ice nucleation activity
  • Plant induction
  • Pre-etz and etz operon

Fingerprint

Dive into the research topics of 'The operon for cytokinin biosynthesis of Erwinia herbicola pv. gypsophilae contains two promoters and is plant induced'. Together they form a unique fingerprint.

Cite this