Autoaggregation of Xylella fastidiosa cells is influenced by type I and type IV pili.
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ABSTRACT:
SUBMITTER: De La Fuente L
PROVIDER: S-EPMC2546647 | biostudies-literature | 2008 Sep
REPOSITORIES: biostudies-literature
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Autoaggregation of Xylella fastidiosa cells is influenced by type I and type IV pili.
De La Fuente Leonardo L Burr Thomas J TJ Hoch Harvey C HC
Applied and environmental microbiology 20080718 17
Autoaggregation of widely dispersed Xylella fastidiosa cells into compact cell masses occurred over a period of hours following 7 to 11 days of growth in microfluidic chambers. Studies involving the use of mutants defective in polarly positioned type I (fimA-negative), type IV (pilB-negative), or both type I and IV (fimA- and pilO-negative) pili revealed the importance and role of pili in the autoaggregation process. ...[more]
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Project description:The phytopathogen Xylella fastidiosa produces two classes of pili, long type IV pili and short type I pili, which are involved in motility and adhesion. In this work, we have investigated the role of σ54 factor and its involvement in the regulation of fimbrial biogenesis in X. fastidiosa. An rpoN null mutant was constructed from citrus strain J1a12, and analyses of global gene expression profile by microarrays comparing the wild type and rpoN mutant strains showed that few genes exhibited differential expression. At least one gene, pilA1 (XF2542), which encodes the structural pilin protein of type IV fimbriae, showed decreased expression in the rpoN mutant whereas an operon encoding proteins of type I fimbriae were twofold more expressed in the mutant. Quantitative real time RT-PCR (qRT-PCR) analysis confirmed that pilA1 transcript was significantly reduced in the rpoN mutant. The transcriptional start site of pilA1 was determined by primer extension, and a canonical σ54-dependent promoter was found upstream of the start site. Genome sequence analysis of X. fastidiosa revealed five paralogues of pilA, but microarray and qRT-PCR data demonstrated that only the pilA1 transcript was significantly affected in the rpoN mutant. The rpoN mutant made more biofilm than the wild type strain and presented a cell-cell aggregative phenotype. These results indicate that σ54 regulates biofilm formation, probably via differential regulation of genes involved in type IV and type I fimbrial biogenesis. Keywords: rpoN mutant strain, pili
2007-10-22 | GSE8097 | GEO
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