title: Low molecular weight plant extract induces metabolic changes and the secretion of extracellular enzymes, but has a negative effect on the expression of the type-III secretion system in Xanthomonas campestris pv. campestris.
abstract: Xanthomonas campestris pathovar campestris (Xcc) is a plant pathogenic bacterium and as such has to adapt to a variety of environments. During the course of disease, Xcc colonizes the surface of its host, infects the xylem in the early stages, and develops a fully saprophytic life-style, aided by secreted degradative enzymes, in the late stages. To get some insight into this complex regulation, Xcc was cultivated in the presence of low molecular weight host plant extract (<10 kDa). From this experiments it could be observed, that malate and sucrose are taken up preferably in such an environment. Furthermore, it was demonstrated, that the plant extract has a negative effect on the gene expression of the hrp-gene cluster, although the activator hrpG was induced. Also, the secretion of degradative enzymes was shown to be upregulated. These observations indicate, that a low molecular weight plant extract (<10 kDa) is a sufficient signal to regulate metabolic pathways and the secretion of enzymes relevant for the development of virulence in Xanthomonas, but has a negative effect on the expression of genes involved in type-III secretion.
authors.affiliation: Bielefeld University, International NRW Graduate School in Bioinformatics and Genome Research, Center for Biotechnology (CeBiTec), Bielefeld, Germany.
authors.forename: Tony Francis
authors.initials: TF
authors.lastname: Watt
authors.forename: Mihael
authors.initials: M
authors.lastname: Vucur
authors.forename: Birgit
authors.initials: B
authors.lastname: Baumgarth
authors.forename: Steven Alexander
authors.initials: SA
authors.lastname: Watt
authors.forename: Karsten
authors.initials: K
authors.lastname: Niehaus
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001937:Brassica / Q000737:chemistry; D015870:Gene Expression / Q000187:drug effects*; D055432:Metabolomics; D010936:Plant Extracts / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism*; D016959:Xanthomonas campestris / Q000201:enzymology / Q000378:metabolism / Q000472:pathogenicity
chemical_list: D001426:Bacterial Proteins; C102404:HrpG protein, Xanthomonas campestris; D010936:Plant Extracts; D014157:Transcription Factors