Abstract
Background Biofilm formation is a complex phenomenon of bacterial cells, involved in several human infections. Its formation is regulated and controlled by several protein factors. The BolA-like proteins (bolAgene) are conserved in both prokaryotes and eukaryotes. The BolA protein is a transcription factor involved in bacterial cell motility and biofilm formation. This study was initiated to elucidate the role of thebolAgene in the curli biogenesis and amyloid production as well as to observe changes in the expression offimH, a fimbriae gene. Methods Knockdown mutants ofEscherichia coliMG1655bolAgene(bolA-KD)were generated using CRISPR interference. The results obtained, were validated through gene expression using RT-PCR, microscopic analysis and different biofilm and amyloid assays. Results ThebolAknockdown mutants showed a decrement in curli amyloid fibers, in fimbriae production and biofilm formation. We have also observed a reduction in EPS formation, eDNA production and extracellular protein content. Gene expression data showed thatbolAdownregulation caused the suppression ofcsgAandcsgDof curli that led to the reduction in curli fiber and the amyloid formation and also the suppression offimH, leading to the loss of fimbriae. Conclusions Curli fibers and fimbriae are found to be involved in biofilm formation leading to the pathogenicity of the bacterial cell. BolA is a conserved protein and is found to play a significant role in curli and fimbriae formation inE. coli.This study further proved that CRISPRi mediated suppression of thebolA gene leads to inhibition of biofilm formation through curli and fimbriae inhibition. Hence, it may be proposed as a possible target for intervention of biofilm mediated infections.