Cloning and expression of the tabtoxin biosynthetic region from Pseudomonas syringae.
AUTOR(ES)
Kinscherf, T G
RESUMO
Pseudomonas syringae BR2, a causal agent of bean wildfire, was subjected to Tn5 mutagenesis in an effort to isolate mutants unable to produce the beta-lactam antibiotic tabtoxin. Three of the tabtoxin-minus (Tox-) mutants generated appeared to have physically linked Tn5 insertions and retained their resistance to the active toxin form, tabtoxnine-beta-lactam (T beta L). The wild-type DNA corresponding to the mutated region was cloned and found to restore the Tn5 mutants to toxin production. The use of cloned DNA from the region as hybridization probes revealed that the region is highly conserved among tabtoxin-producing pathovars of P. syringae and that the region deletes at a relatively high frequency (10(-3)/CFU) in BR2. The Tox- deletion mutants also lost resistance to tabtoxinine-beta-lactam. A cosmid designated pRTBL823 restored toxin production and resistance to BR2 deletion mutants. This cosmid also converted the tabtoxin-naive P. syringae epiphyte Cit7 to toxin production and resistance, indicating that pRTBL823 contains a complete set of biosynthetic and resistance genes. Tox- derivatives of BR2 did not produce disease symptoms on bean. Clones that restored toxin production to both insertion and deletion mutants also restored the ability to cause disease. However, tabtoxin-producing Cit7 derivatives remained nonpathogenic on bean and tobacco, suggesting that tabtoxin production alone is not sufficient to cause disease.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=208062Documentos Relacionados
- Regulation of tabtoxin production by the lemA gene in Pseudomonas syringae.
- Characterization of the alginate biosynthetic gene cluster in Pseudomonas syringae pv. syringae.
- Molecular cloning and biological characterization of the recA gene from Pseudomonas syringae.
- DNA sequence and transcriptional analysis of the tblA gene required for tabtoxin biosynthesis by Pseudomonas syringae.
- Induction of the copper resistance operon from Pseudomonas syringae.