Effects of phosphorelay perturbations on architecture, sporulation, and spore resistance in biofilms of Bacillus subtilis.
The spore-forming bacterium Bacillus subtilis is able to form highly organized multicellular communities called biofilms. This coordinated bacterial behavior is often lost in domesticated or laboratory strains as a result of planktonic growth in rich media for many generations. However, we show here that the laboratory strain B. subtilis 168 is still capable of forming spatially organized multicellular communities on minimal medium agar plates, exemplified by colonies with vein-like structures formed by elevated bundles of cells. In line with the current model for biofilm formation, we demonstrate that overproduction of the phosphorelay components KinA and Spo0A stimulates bundle formation, while overproduction of the transition state regulators AbrB and SinR leads to repression of formation of elevated bundles. Time-lapse fluorescence microscopy studies of B. subtilis green fluorescent protein reporter strains show that bundles are preferential sites for spore formation and that flat structures surrounding the bundles contain vegetative cells. The elevated bundle structures are formed prior to sporulation, in agreement with a genetic developmental program in which these processes are sequentially activated. Perturbations of the phosphorelay by disruption and overexpression of genes that lead to an increased tendency to sporulate result in the segregation of sporulation mutations and decreased heat resistance of spores in biofilms. These results stress the importance of a balanced control of the phosphorelay for biofilm and spore development.
Moleculart Genetics Group, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Kerklaan 30, 9751 NN Haren, The Netherlands.
Jan-Willem
JW
Veening
Oscar P
OP
Kuipers
Stanley
S
Brul
Klaas J
KJ
Hellingwerf
Remco
R
Kort
D000222:Adaptation, Physiological; D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D018441:Biofilms / Q000254:growth & development*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D017353:Gene Deletion; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D009024:Morphogenesis; D010784:Photomicrography; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D013171:Spores, Bacterial / Q000502:physiology*; D013194:Staining and Labeling; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
C060762:AbrB protein, Bacillus subtilis; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; C075521:kinA protein, Bacillus subtilis; D049452:Green Fluorescent Proteins; C076733:FlaD protein, Bacteria; D011494:Protein Kinases