Li Cheng, Qi Cai, Yang Sirui, Li Zhengyi, Ren Biao, Li Jiyao, Zhou Xuedong, Cai Huawei, Xu Xin, Peng Xian
State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Front Microbiol. 2022 Jan 31;12:777504. doi: 10.3389/fmicb.2021.777504. eCollection 2021.
The phenotypic traits of , such as fluoride tolerance, are usually associated with genotypic alterations. The aim of this study was to identify adaptive mutations of to gradient fluoride concentrations and possible relationships between the mutations and fluoride tolerance. We identified a highly resistant strain (FR1000) with a novel single nucleotide polymorphism (SNP, -36G→T) in the promoter region of FF-ATPase gene cluster () resistant to 1,000 ppm fluoride using the whole-genome Illumina PE250 sequencing. Thus, a -36G→T FF-ATPase promoter mutation from the parental strain UA159 was constructed and named UA159-T. qRT-PCR showed that the FF-ATPase gene expression of both FR1000 and UA159-T was up-regulated, and fluoride tolerance of UA159-T was significantly improved. Complementation of Dicyclohexylcarbodiimide (DCCD), a specific inhibitor of FF-ATPase, increased fluoride susceptibility of FR1000 and UA159-T. Intracellular fluoride concentrations of fluoride tolerance strains were higher compared to UA159 strain as demonstrated by F analysis. Further validation with rat caries models showed that UA159-T caused more severe caries lesions under fluoride exposure compared with its parental UA159 strain. Overall, the identified -36G→T mutation in the promoter region of FF-ATPase gene drastically contributed to the fluoride tolerance and enhanced cariogenicity of . These findings provided new insights into the mechanism of microbial fluoride tolerance, and suggested FF-ATPase as a potential target for suppressing fluoride resistant strains.
诸如耐氟性等的表型特征通常与基因型改变相关。本研究的目的是鉴定[具体微生物名称]对梯度氟浓度的适应性突变以及这些突变与耐氟性之间的可能关系。我们使用全基因组Illumina PE250测序鉴定出一株对1000 ppm氟具有高度抗性的[具体微生物名称]菌株（FR1000），其在FF - ATPase基因簇（[具体基因簇名称]）的启动子区域存在一个新的单核苷酸多态性（SNP，-36G→T）。因此，构建了来自亲本菌株[具体亲本菌株名称] UA159的 -36G→T FF - ATPase启动子突变体，并命名为UA159 - T。qRT - PCR表明FR1000和UA159 - T的FF - ATPase基因表达均上调，且UA159 - T的耐氟性显著提高。FF - ATPase的特异性抑制剂二环己基碳二亚胺（DCCD）的互补作用增加了FR1000和UA159 - T对氟的敏感性。通过F分析表明，与UA159菌株相比，耐氟菌株的细胞内氟浓度更高。用大鼠龋齿模型进一步验证表明，与亲本UA159菌株相比，UA159 - T在氟暴露下导致更严重的龋损。总体而言，在FF - ATPase基因启动子区域鉴定出的 -36G→T突变极大地促进了[具体微生物名称]的耐氟性并增强了其致龋性。这些发现为微生物耐氟机制提供了新的见解，并表明FF - ATPase作为抑制耐氟菌株的潜在靶点。
