Genomic instability of TnSMU2 contributes to Streptococcus mutans biofilm development and competence in a cidB mutant.
Genomic instability of TnSMU2 contributes to Streptococcus mutans biofilm development and competence in a cidB mutant.
复制标题
TnSMU2 的基因组不稳定性有助于变形链球菌生物膜的发育和 CIDB 突变体的能力。
DOI：
10.1002/mbo3.934
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发表时间：
2019
期刊：
影响因子：
3.4
通讯作者：
Rice,KellyC
中科院分区：
文献类型：
--
作者：
Turner,MatthewE;Huynh,Khanh;Carney,O'neshiaV;Gross,Dennis;Carroll,RonanK;Ahn,Sang-Joon;Rice,KellyC
变形链球菌是口腔中的主要致病菌，也是龋齿的主要致病菌。帖前mutansCid/Lrg系统可能有助于耐受在这种环境中遇到的应激，因为突变体和/或lrg突变体表现出改变的氧化应激敏感性、遗传能力和生物膜表型。最近注意到，cidB突变体具有两种稳定的菌落形态：“粗糙”表型（类似于野生型）和“光滑”表型。在我们先前发表的工作中，thecidBrough突变体表现出对氧化应激的敏感性增加，RNAseq确定了中心碳代谢和氧化应激反应基因的广泛转录组学变化。在本报告中，我们对野生型、Bmb Brough和Bmb smooth突变体进行了基于Illumina的基因组重测序，并比较了它们对氧化和酸胁迫的抗性、生物膜形成和感受态表型。在琼脂平板上，在无菌生长过程中，以及在1 mM过氧化氢存在下，两种突变体均表现出相当的需氧生长抑制。ThecidBsmooth突变体在BHI中表现出显着的能力缺陷，这可以通过合成CSP来挽救。两种突变体也显示出降低的XIP介导的能力，尽管这种降低在cidBsmooth突变体中更明显。thecidBsmooth突变体的厌氧生物膜显示出碘化丙啶染色增加，但相应的生物膜CFU数据表明这种表型是由于细胞损伤而不是细胞死亡增加。ThecidBrough厌氧生物膜显示相对于野生型改变的结构（减少的生物量和平均厚度），其与减少的CFU计数相关。测序结果显示，cidBsmooth突变体具有约78 kb的DNA片段缺失，对应于TnSMU 2基因组岛及其3′端侧翼基因。因此，这可能是独特的生物膜和感受态表型thecidBsmooth突变体的基因组变化在这一地区。
Streptococcus mutansis a key pathogenic bacterium in the oral cavity and a primary contributor to dental caries. TheS. mutansCid/Lrg system likely contributes to tolerating stresses encountered in this environment ascidand/orlrgmutants exhibit altered oxidative stress sensitivity, genetic competence, and biofilm phenotypes. It was recently noted that thecidBmutant had two stable colony morphologies: a “rough” phenotype (similar to wild type) and a “smooth” phenotype. In our previously published work, thecidBrough mutant exhibited increased sensitivity to oxidative stress, and RNAseq identified widespread transcriptomic changes in central carbon metabolism and oxidative stress response genes. In this current report, we conducted Illumina‐based genome resequencing of wild type,cidBrough, andcidBsmooth mutants and compared their resistance to oxidative and acid stress, biofilm formation, and competence phenotypes. BothcidBmutants exhibited comparable aerobic growth inhibition on agar plates, during planktonic growth, and in the presence of 1 mM hydrogen peroxide. ThecidBsmooth mutant displayed a significant competence defect in BHI, which was rescuable by synthetic CSP. BothcidBmutants also displayed reduced XIP‐mediated competence, although this reduction was more pronounced in thecidBsmooth mutant. Anaerobic biofilms of thecidBsmooth mutant displayed increased propidium iodide staining, but corresponding biofilm CFU data suggest this phenotype is due to cell damage and not increased cell death. ThecidBrough anaerobic biofilms showed altered structure relative to wild type (reduced biomass and average thickness) which correlated with decreased CFU counts. Sequencing data revealed that thecidBsmooth mutant has a unique “loss of read coverage” of ~78 kb of DNA, corresponding to the genomic island TnSMU2 and genes flanking its 3′ end. It is therefore likely that the unique biofilm and competence phenotypes of thecidBsmooth mutant are related to its genomic changes in this region.