Constitutive abrB expression suppresses cell differentiation, restoring growth defect of a genome-reduced Bacillus subtilis strain and enhancing bioproduction

ABSTRACT: Genome-reduced strains have numerous beneficial traits such as improvement of bioproduction, better growth fitness and cell yield, since deleting large non-essential parts of the genomes enables removal of competing and unwanted metabolic pathways, however, can also result in undesirable phenotypes, such as growth defects. This was also the case for Bacillus subtilis MGB874 (Genome reduction strain, Morimoto et al., 2008), which has the excellent feature of increasing the productivity of cellulases and proteases, but also has the negative aspect of a reduced growth rate. B. subtilis is a soil bacterium that differentiates into various cells to form multicellular communities, but the related genes have to be strictly silenced by global transcription factor, AbrB, since expression of such genes are detrimental to vegetative growth during the exponential growth phase. We found that in MGB874, genes that should be repressed by AbrB was up-regulated and genes in the central metabolic pathway were down-regulated, and thus speculated that this might be the cause of the growth defect in MGB874. By constitutively expressing the abrB gene at a high level to enable strict repression by AbrB, the gene expression and metabolic flux of the central metabolic pathways were increased and the growth rate was restored to the wild-type level. This improvement also enhanced productivity of γ-PGA. To investigate gene-expression alteration in the genome reduced bacteria with the global transcriptional regulator (silencer), we performed transcriptome analysis of the wild type and the genome reduced B. subtilis cells using custom tiling arrays.

ORGANISM(S): Bacillus subtilis subsp. subtilis str. 168

SUBMITTER: Taku Oshima 

PROVIDER: E-MTAB-11245 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress