An ice nucleation reporter gene system: identification of inducible pathogenicity genes in Pseudomonas syringae pv. phaseolicola.

摘要: We have constructed derivatives of the transposon Tn3 that allow an ice nucleation gene (inaZ) to be used as 'reporter' transcriptional activity genes into which it is inserted. In these (Tn3-Ice and Tn3-Spice), lacZYA sequences Tn3-HoHo1 were replaced with inaZ lacking its native promoter. The virB::inaZ fusions in correct orientation was inducible by acetosyringone, a plant metabolite activates vir operon Agrobacterium tumefaciens Ti plasmids, while opposite unresponsive inducer. Tn3-Spice also investigate expression cluster (hrp) control pathogenicity hypersensitivity elicited Pseudomonas syringae pv. phaseolicola. An region identified expressed at low levels vitro but becomes activated when bacteria come contact susceptible host, bean. Activation this occurred within 2 h post-inoculation nearly complete time began multiply leaf tissue. reporter appears least 10(5)-fold more sensitive than lacZ P.s.phaseolicola. Thus, fusion system provides sensitive, convenient inexpensive tool for study bacterial expression, particularly during pathogenesis, should generally useful Gram-negative bacteria.