title: A simple method for in vivo expression studies of Xanthomonas axonopodis pv. citri.
abstract: A major problem in studying bacterial plant pathogens is obtaining the microorganism directly from the plant tissue to perform in vivo expression (protein or mRNA) analyses. Here we report an easy and fast protocol to isolate Xanthomonas axonopodis pv. citri directly from the host plant, in sufficient amounts to perform protein fingerprinting by 2-D gel electrophoresis as well as RNA expression assays. The protein profile obtained was very similar to that of X. axonopodis pv. citri grown in the presence of a leaf extract of Citrus sinensis; however, some differential proteins expressed in vivo were observed. Total RNA extraction revealed typical 16S and 23S bands in the agarose gel, and RT-PCR reactions using primers specific for genes of the bacterium confirmed the quality of the RNA preparation. Also, RT-PCR reactions using plant ribosomal primers were employed, and no amplification product was obtained, indicating that plant RNA is not present in the bacterium RNA sample.
authors.affiliation: EMBRAPA-CENARGEN, Parque Estacção Biológica Final Av. W/5 Norte, CEP 70770-900, Brasilia, DF, Brazil. amehta@cenargen.embrapa.br
authors.forename: Angela
authors.initials: A
authors.lastname: Mehta
authors.forename: Yoko B
authors.initials: YB
authors.lastname: Rosato
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics / Q000302:isolation & purification; D032084:Citrus sinensis / Q000382:microbiology*; D004268:DNA-Binding Proteins / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D015870:Gene Expression; D018515:Plant Leaves / Q000382:microbiology; D020543:Proteome / Q000032:analysis* / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000032:analysis* / Q000302:isolation & purification; D012335:RNA, Ribosomal / Q000032:analysis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D000071336:Transcription Activator-Like Effectors; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D014974:Xanthomonas / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C083180:Mob protein, Bacteria; D020543:Proteome; C077723:PthA protein, Xanthomonas campestris; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D000071336:Transcription Activator-Like Effectors; D014157:Transcription Factors; C075973:CAP-like protein, Xanthomonas campestris