Molecular Plant Pathology · 2000 · 21 citations · 16 references
AgriculturePlant BiologyPlant PathologyBacterial Plant PathologyPlant Molecular BiologyPlant-microbe InteractionsBacterial Plant PathogensBacterial Spot DiseasesPathogen RecognitionPlant Disease ResistancePlant PathogenesisPlant-pathogen InteractionsAvirulence ProteinsHost Resistance GenesHypersensitive Response ElicitationNuclear Localization SignalsPathogen Resistance GenesPathogenesis Of Plant-associated BacteriaPathogenicity DeterminantsPlant Pathogen Effectors
Abstract Xanthomonas campestris pv. vesicatoria (Xcv) is the causal agent of bacterial spot disease on pepper and tomato. Pathogenicity on susceptible plants and the induction of the hypersensitive reaction (HR) on resistant plants requires a number of genes, designated hrp, most of which are clustered in a 23-kb chromosomal region. Nine hrp genes encode components of a type III protein secretion apparatus that is conserved in Gram-negative plant and animal pathogenic bacteria. We have recently demonstrated that Xcv secretes proteins into the culture medium in a hrp-dependent manner. Substrates of the Hrp secretion machinery are pathogenicity factors and avirulence proteins, e.g. AvrBs3. The AvrBs3 protein governs recognition, i.e. HR induction, when bacteria infect pepper plants carrying the corresponding resistance gene Bs3. Intriguingly, the AvrBs3 protein contains eukaryotic signatures such as nuclear localization signals (NLS), and has been shown to act inside the plant cell. We postulate that AvrBs3 is transferred into the plant cell via the Hrp type III pathway and that recognition of AvrBs3 takes place in the plant cell nucleus.
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Céline Agrain, Isabel Sorg, Cécile Paroz et al. · Molecular Microbiology · 2005 · 307 citations · Full text