芽孢杆菌菌株广泛分布于陆地和海洋环境,其中一些因其生物膜形成能力而被用作生物防治生物。在枯草芽孢杆菌中,生物膜的形成是通过复杂的网络进行微调的,要清楚地了解这一点仍然需要研究。在细菌中,tmRNA,由ssrA基因编码,催化转译,可以挽救在缺乏功能终止密码子的mRNA转录本上停滞的核糖体。tmRNA也影响一些细菌的生理生物过程。在这项研究中,我们在枯草芽孢杆菌中构建了一个ssrA突变体,发现ssrA突变体的生物膜形成在很大程度上受到了损害。此外,我们分离出了ssrA的生物膜形成抑制因子,其中生物膜形成恢复到甚至比野生型更强的水平。我们进一步用野生型进行RNAseq测定,ssrA突变体,和ssrA的抑制子,用于比较它们的转录组。通过分析转录组数据,我们预测了一些差异表达基因(DEGs)在枯草芽孢杆菌生物膜形成的tmRNA调控中的可能功能。最后,我们发现两个DEG的过度表达,acoA和yhjR,可以恢复ssrA突变体中生物膜的形成,这表明AcoA和YhjR是参与控制枯草芽孢杆菌生物膜形成的tmRNA调控网的直接调节因子。我们的数据可以提高有关芽孢杆菌生物膜形成中涉及的分子网络的知识,并为将来研究芽孢杆菌生物膜的操作提供新的靶标。
Bacillus strains are widely distributed in terrestrial and marine environments, and some of them are used as biocontrol organisms for their biofilm-formation ability. In Bacillus subtilis, biofilm formation is fine-tuned by a complex network, a clear understanding of which still requires study. In bacteria,
tmRNA, encoded by the ssrA gene, catalyzes trans-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 a ssrA mutant in B. subtilis and found that the biofilm formation in the ssrA mutant was largely impaired. Moreover, we isolated a biofilm-formation suppressor of ssrA, 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, ssrA mutant, and suppressor of ssrA for 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 in B. subtilis. Finally, we found that the overexpression of two DEGs, acoA and yhjR, could restore the biofilm formation in the ssrA mutant, indicating that AcoA and YhjR were immediate regulators involved in the
tmRNA regulatory web controlling biofilm formation in B. subtilis. Our data can improve the knowledge about the molecular network involved in Bacillus biofilm formation and provide new targets for manipulation of Bacillus biofilms for future investigation.