Virulence-inducing phenolic compounds detected by Agrobacterium tumefaciens

• Published in: ACS symposium series
• Main Authors: Spencer P.A, Towers G.H.N
• Format: Journal Article
• Language: English
• Published: 1989
• Subjects: agrobacterium tumefaciens; compose phenolique; compuestos fenolicos; pathogenicity; phenolic compounds; poder patogeno; pouvoir pathogene
• ISSN: 0097-6156; 1947-5918

Construction of vir::lacZ fusion reporter genes and subsequent analysis of their expression in strains of Agrobacterium tumefaciens has permitted the discovery of a class of phytochemicals that this pathogen detects and which induce virulence. Preliminary screening of a variety of commercially available phenolics revealed that some were active as vir inducers. Two acetophenones were isolated from transformed tobacco root cultures. The results of a recent study by us indicate that there exists a range of virulence-inducing plant phenolics which are not limited to acetophenones but include chalcones as well as cinnamic acid derivatives. Among the latter are acids, alcohols and esters known to be associated with plant cell walls or implicated in lignin biosynthesis, a discovery which suggests that this wide host range pathogen likely responds to chemicals common to all susceptible hosts. We are currently studying signal compounds and natural inhibitors in relation to the host range of Agrobacterium strains. Activity was detected in extracts from a grapevine tissue culture, grapevine bark, and flavan-containing fractions obtained from grapes. In addition, as yet unidentified compounds inhibitory to vir-induction have been discovered.