Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 9, 2003
Publication Date: February 1, 2004
Citation: Kong, H.N., Patterson, C.D., Mitchell, R., Lydon, J. 2004. The characterization of genes required for tagetitoxin production, a chloroplast rna polymerase inhibitor produced by pseudomonas syringae pv. tagetis [abstract]. Weed Science Society of America Meeting Abstracts. 44:22.
Studies were conducted to identify genes required for tagetitoxin production by Pseudomonas syringae pv. tagetis. Mutants of P.s. pv. tagetis strain EB037, originally isolated from common ragweed (Ambrosia artemisiifolia L.), were produced using Tn5 mutagenesis. Seventeen nontagetitoxin mutants were isolated and the DNA surrounding the Tn5 insertion sites in several of the mutants was analyzed. One mutant, designated Tox-9, has a mutation in a DNA region having a high degree of homology with exbD, a gene that encodes for an auxiliary protein in the TonB/ExbD/ExbB membrane transport system. A second mutant, designated Tox-10, has a mutation in a DNA region having a high degree of homology with asnB, a gene that encodes for an asparagine synthetase. A third mutant, designated Tox-12, has a mutation in a DNA region having a high degree of homology with cysD, a gene that encodes for a sulfate adenylate transferase. Two other mutants, designated Tox-17 and Tox-18, have mutations in genes with very high homology to the gacS and gacA genes that encode a two-component regulatory system. The mutated genes characterized represent genes that may be involved in several aspects of tagetitoxin production, such as regulation, biosynthesis (the structure contains a sulphur molecule in one ring and two nitrogen moieties attached to the rings), and transport. However, none of genes have been shown to be physically linked in a region small enough to represent a production gene cluster.