Strategies in pathogenesis: mechanistic specificity in the detection of generic signals.

Full Abstract

The virulence genes of the plant pathogen Agrobacterium tumefaciens are induced by more than 40 low-molecular-weight phenolic compounds. The prevailing opinion is that (i) wound-derived phenols produced on breach of the integrity of the cell wall act as the initiating signal in a series of events which results in host cell transformation, and (ii) a classical membrane receptor, putatively VirA, is responsible for the recognition of all such phenolic inducers. Here, we argue that the discovery of the subset of inducers that are relatives of the dehydrodiconiferyl alcohol glucoside (DCG) growth factors redirects our attention to work on the plant wound as a site of cell division, and suggests that we further explore the implications of early work on the relationship between transformation efficiency and the status of the cell cycle of the host. In addition, we argue that the significant structural diversity allowed in the para position of the phenol ring of inducers suggests that a receptor-ligand interaction based solely on structural recognition is insufficient, but that recognition followed by a specific proton transfer event may be sufficient to explain vir induction activity. Hence, the specificity of the response of A. tumefaciens may be a consequence of the features required for a chemical reaction to occur on the receptor surface. Finally, we review affinity labelling studies which exploit this phenol detection mechanism and which provide evidence that the phenol receptor may be other than VirA, the sensory kinase of the two component regulatory system implicated in Agrobacterium virulence.(ABSTRACT TRUNCATED AT 250 WORDS)

Author information

Author/s: Duban, M E (ME); Lee, K (K); Lynn, D G (DG);

Affiliation: Searle Chemistry Laboratory, University of Chicago, Illinois 60637.

Grants: GM07183-18 (Agency:NIGMS NIH HHS) ; GM47369 (Agency:NIGMS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.; Review

Journal: Molecular microbiology (Mol Microbiol), published in ENGLAND. (Language: eng)

Reference: 1993-Mar; vol 7 (issue 5) : pp 637-45

Dates: Created 1993/05/13; Completed 1993/05/13; Revised 2007/11/14;

PMID: 8469110, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Acetophenones - chemistry; pharmacology
Bacterial Proteins - genetics; metabolism
Cell Division
Cell Transformation, Neoplastic - genetics
Gene Expression Regulation, Bacterial - drug effects
Models, Biological
Phenols - chemistry; pharmacology
Plant Diseases - genetics; microbiology

Plants - chemistry; microbiology
Plasmids - genetics
Rhizobium radiobacter - drug effects; genetics; pathogenicity
Signal Transduction
Structure-Activity Relationship
Transfection
Virulence - genetics
Virulence Factors

Associated Chemicals: Acetophenones (0) ; Bacterial Proteins (0) ; Phenols (0) ; Virulence Factors (0) ; acetosyringone (2478-38-8) ; dehydrodiconiferyl alcohol (4263-87-0)

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