Transcriptomic Analysis Reveals the Role of tmRNA on Biofilm Formation in Bacillus subtilis

Bacillusstrains are widely distributed in terrestrial and marine environments, and some of them are used as biocontrol organisms for their biofilm-formation ability. InBacillus subtilis, biofilm formation is fine-tuned by a complex network, a clear understanding of which still requires study. In bacteria, tmRNA, encoded by thessrAgene, catalyzestrans-translation that can rescue ribosomes stalled on mRNA transcripts lacking a functional stop codon. tmRNA also affects physiological bioprocesses in some bacteria. In this study, we constructed assrAmutant inB. subtilisand found that the biofilm formation in thessrAmutant was largely impaired. Moreover, we isolated a biofilm-formation suppressor ofssrA, in which the biofilm formation was restored to a level even stronger than that in the wild type. We further performed RNAseq assays with the wild type,ssrAmutant, and suppressor ofssrAfor comparisons of their transcriptomes. By analyzing the transcriptomic data, we predicted the possible functions of some differentially expressed genes (DEGs) in the tmRNA regulation of biofilm formation inB. subtilis. Finally, we found that the overexpression of two DEGs,acoAandyhjR, could restore the biofilm formation in thessrAmutant, indicating that AcoA and YhjR were immediate regulators involved in the tmRNA regulatory web controlling biofilm formation inB. subtilis. Our data can improve the knowledge about the molecular network involved inBacillusbiofilm formation and provide new targets for manipulation ofBacillusbiofilms for future investigation.Keywords:tmRNA;biofilm formation;Bacillus subtilis;transcriptome;sporulation