Disease relevance of Tabtoxin

• Coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of Pseudomonas syringae, and each contributes significantly to bacterial virulence in plants [1].
• In contrast to the phenotype of a P. syringae pv. syringae lemA mutant, the Tox- mutants of P. syringae pv. coronafaciens were still able to produce necrotic lesions on oat plants (Avena sativa), although without the chlorosis associated with tabtoxin production [2].
• Bacterial growth was determined by cell density, and tabtoxin production was measured by the E. coli bioassay technique [3].

High impact information on Tabtoxin

• DNA sequence and transcriptional analysis of the tblA gene required for tabtoxin biosynthesis by Pseudomonas syringae [4].
• Marker exchange mutagenesis of the tblA locus resulted in loss of tabtoxin production [2].
• 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 [5].
• The primary target of tabtoxin is presumed to be glutamine synthetase [6].
• We also isolated three S. cerevisiae DNA inserts of 2.1, 2.3, and 2.8 kilobases that conferred tabtoxin and MSO resistance when the inserts were present on a multicopy plasmid [6].

Biological context of Tabtoxin

• As part of our investigation of the self-protection mechanism(s) used by these pathovars, we have determined that GS becomes adenylylated after toxin production is initiated and that the serine released from the zinc-activated hydrolysis of tabtoxin is a factor in the initiation of this adenylylation [7].
• The biosynthetic gene cluster for the beta-lactam antibiotic tabtoxin in Pseudomonas syringae [8].
• Tabtoxin resistance protein (TTR) is an enzyme that catalyzes the acetylation of tabtoxin rendering tabtoxin-producing pathogens tolerant to their own phytotoxins [9].

Analytical, diagnostic and therapeutic context of Tabtoxin

• Two sets of PCR primers were developed to amplify genes (tblA and tabA) required for tabtoxin production [10].
• Site-directed mutagenesis and preliminary x-ray crystallographic studies of the tabtoxin resistance protein [9].

References