Control of temperature-responsive synthesis of the phytotoxin coronatine in Pseudomonas syringae by the unconventional two-component system CorRPS. J Mol Microbiol Biotechnol 2002 May;4(3):191-6
Date
04/05/2002Pubmed ID
11931546Scopus ID
2-s2.0-0036195643 (requires institutional sign-in at Scopus site) 18 CitationsAbstract
The phytopathogen Pseudomonas syringae produces the phytotoxin coronatine (COR) as a major virulence factor. COR and its precursor, coronafacic acid, function as molecular mimics of the plant signaling molecule jasmonate. A 32.8-kb plasmid-borne gene cluster mediates COR biosynthesis, which is optimal at 18 degrees C and non-detectable at 28 degrees C, the optimal growth temperature for P. syringae. The thermoregulation is mediated at the transcriptional level by an unconventional two-component regulatory system consisting of a histidine protein kinase, CorS, and two transcriptional activators, CorR and CorP. Dissection of this regulatory triad revealed that CorR binds to its target sequences in a thermoresponsive manner and that its DNA-binding activity is controlled by CorS. A Preliminary model for thermo-sensing by CorS is proposed based on its membrane topology and the analysis of translational fusions of CorS to reporter enzymes at different temperatures. CorP lacks a typical helix-turn-helix motif but possibly functions as a modulator of CorR or CorS activity. The thermoregulation of COR biosynthetic genes is widespread among various COR-producing P. syringae strains. Post-translational processes also contribute to the thermo-responsiveness of COR production. Additionally, COR synthesis in P. syringae is influenced by nutrient availability, rpoN encoding the alternative sigma factor sigma54, and HrpV, a negative regulator of hrp gene expression, suggesting a complex regulatory network governing phytotoxin synthesis.
Author List
Smirnova AV, Wang L, Rohde B, Budde I, Weingart H, Ullrich MSMESH terms used to index this publication - Major topics in bold
Amino AcidsBacterial Proteins
Bacterial Toxins
DNA-Binding Proteins
Gene Expression Regulation, Bacterial
Genes, Bacterial
Indenes
Multigene Family
Plant Diseases
Pseudomonas
Signal Transduction
Temperature
Trans-Activators