title: Specificity of signal molecules in the activation of Agrobacterium virulence gene expression.
abstract: The activation of the Agrobacterium virulence system is known to be induced by certain phenolic compounds. We have tested the vir-inducing ability of fifty compounds, by using a virB-lacZ gene fusion, and analysed the relationship between structure and activity of these compounds. In this way we have identified several new vir-inducers: coniferylalcohol, 3,5-dimethoxy-4-hydroxybenzene, homovanillic acid, ferulic acid, 3-ethoxy-4-hydroxybenzaldehyde and guaiacol, all of which are compounds with strong or moderate activity and four compounds with weak vir-inducing activity. In view of the specificity of vir-inducers, our data extended observations of others and enabled us to define the specific structural features of a vir-inducer molecule. In addition we show here that induction of the octopine Ti vir-genes is (i) optimal at 29 degrees C and totally abolished at 37 degrees C, and (ii) strongly inhibited at low concentrations of sodium chloride. The implications for plant transformation are discussed.
authors: Department of Plant Molecular Biology, Leiden University, The Netherlands.
authors: L S
authors: LS
authors: Melchers
authors: A J
authors: AJ
authors: Regensburg-Tuïnk
authors: R A
authors: RA
authors: Schilperoort
authors: P J
authors: PJ
authors: Hooykaas
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D005786:Gene Expression Regulation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D015394:Molecular Structure; D009154:Mutation; D012231:Rhizobium / Q000235:genetics* / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D000098:Acetophenones; D012965:Sodium Chloride; C051667:acetosyringone