title: Bacillus subtilis biofilm induction by plant polysaccharides.
abstract: Bacillus subtilis is a plant-beneficial Gram-positive bacterium widely used as a biofertilizer. However, relatively little is known regarding the molecular processes underlying this bacterium's ability to colonize roots. In contrast, much is known about how this bacterium forms matrix-enclosed multicellular communities (biofilms) in vitro. Here, we show that, when B. subtilis colonizes Arabidopsis thaliana roots it forms biofilms that depend on the same matrix genes required in vitro. B. subtilis biofilm formation was triggered by certain plant polysaccharides. These polysaccharides served as a signal for biofilm formation transduced via the kinases controlling the phosphorylation state of the master regulator Spo0A. In addition, plant polysaccharides are used as a source of sugars for the synthesis of the matrix exopolysaccharide. The bacterium's response to plant polysaccharides was observed across several different strains of the species, some of which are known to have beneficial effects on plants. These observations provide evidence that biofilm genes are crucial for Arabidopsis root colonization by B. subtilis and provide insights into how matrix synthesis may be triggered by this plant.
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Pascale B
authors.initials: PB
authors.lastname: Beauregard
authors.forename: Yunrong
authors.initials: Y
authors.lastname: Chai
authors.forename: Hera
authors.initials: H
authors.lastname: Vlamakis
authors.forename: Richard
authors.initials: R
authors.lastname: Losick
authors.forename: Roberto
authors.initials: R
authors.lastname: Kolter
mesh_terms: D000704:Analysis of Variance; D017360:Arabidopsis; D001412:Bacillus subtilis / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D002244:Carbon / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005109:Extracellular Matrix / Q000378:metabolism*; D005434:Flow Cytometry; D005685:Galactans; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D013045:Species Specificity; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D005685:Galactans; D011134:Polysaccharides; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; D002244:Carbon; C005653:arabinogalactan