Previous Article | Next Article ![]()
J. Bacteriol., 08 1995, 4457-4465, Vol 177, No. 15
A Lichter, I Barash, L Valinsky and S Manulis
A locus conferring cytokinin production was previously isolated from the
gall-forming bacterium Erwinia herbicola pv. gypsophilae. This locus
resided in a cluster with the genes specifying indole-3-acetic acid
production on the pathogenicity-associated plasmid pPATH (A. Lichter, S.
Manulis, O. Sagee, Y. Gafni, J. Gray, R. Meilen, R. O. Morris, and I.
Barash, Mol. Plant Microbe Interact., 8:114-121, 1995). Sequence analysis
of this locus indicated the presence of a cytokinin biosynthesis gene (etz)
homologous to other described cytokinin biosynthesis genes. A unique open
reading frame (pre-etz) encoding 169 amino acids preceded etz and together
with etz formed a region with a distinctive low G+C content. Northern (RNA)
analysis indicated the presence of an etz-specific transcript of 1 kb and a
common transcript for pre-etz and etz of 1.4 kb. The level of the 1-kb
transcript was high in the late logarithmic phase and very low in the
stationary phase. In contrast, the level of the 1.4-kb transcript was lower
than that of the 1-kb transcript in the late logarithmic phase and
predominant in the stationary phase. A marker exchange mutant of etz which
did not produce cytokinins exhibited a reduction in gall size on Gypsophila
cuttings and almost abolished disease symptoms in a whole- plant assay.
Complementation of this marker exchange mutant with the intact etz gene on
a multicopy plasmid resulted in overproduction of cytokinins and larger
plant galls from which small shoots emerged. Insertional mutation in
pre-etz resulted in a sharp decrease in both the level of the etz-specific
transcript and cytokinin production.(ABSTRACT TRUNCATED AT 250 WORDS)
Copyright © 1995, American Society for Microbiology
The genes involved in cytokinin biosynthesis in Erwinia herbicola pv. gypsophilae: characterization and role in gall formation
Department of Botany, Faculty of Life Science, Tel Aviv University, Israel.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |