Muñoz-Villagrán Claudia Melissa, Mendez Katterinne N, Cornejo Fabian, Figueroa Maximiliano, Undabarrena Agustina, Morales Eduardo Hugo, Arenas-Salinas Mauricio, Arenas Felipe Alejandro, Castro-Nallar Eduardo, Vásquez Claudio Christian
Laboratorio de Microbiología Molecular, Departamento de Biología, Universidad de Santiago de Chile, Santiago, Chile.
Departamento de Ciencias Básicas, Facultad de Ciencia, Universidad Santo Tomas Sede Santiago, Santiago, Chile.
PeerJ. 2018 Feb 19;6:e4402. doi: 10.7717/peerj.4402. eCollection 2018.
The genus is a cosmopolitan and diverse group of aerobic, cold-adapted, Gram-negative bacteria exhibiting biotechnological potential for low-temperature applications including bioremediation. Here, we present the draft genome sequence of a bacterium from the genus isolated from a sediment sample from King George Island, Antarctica (3,490,622 bp; 18 scaffolds; G + C = 42.76%). Using phylogenetic analysis, biochemical properties and scanning electron microscopy the bacterium was identified as BNF20, making it the first genome sequence reported for this species. BNF20 showed high tellurite (MIC 2.3 mM) and chromate (MIC 6.0 mM) resistance, respectively. Genome-wide nucleotide identity comparisons revealed that BNF20 is highly similar (>90%) to other uncharacterized spp. such as JCM18903, JCM18902, and P11F6. Bayesian multi-locus phylogenetic analysis showed that BNF20 belongs to a polyphyletic clade with other bacteria isolated from polar regions. A high number of genes related to metal(loid) resistance were found, including tellurite resistance genetic determinants located in two contigs: Contig LIQB01000002.1 exhibited five ter genes, each showing putative promoter sequences (terACDEZ), whereas contig LIQB1000003.2 showed a variant of the terZ gene. Finally, investigating the presence and taxonomic distribution of ter genes in the NCBI's RefSeq bacterial database (5,398 genomes, as January 2017), revealed that 2,623 (48.59%) genomes showed at least one ter gene. At the family level, most (68.7%) genomes harbored one ter gene and 15.6% exhibited five (including BNF20). Overall, our results highlight the diverse nature (genetic and geographic diversity) of the genus, provide insights into potential mechanisms of metal resistance, and exemplify the benefits of sampling remote locations for prospecting new molecular determinants.
该属是一类分布于全球的多样化需氧、冷适应革兰氏阴性菌，在包括生物修复在内的低温应用方面展现出生物技术潜力。在此，我们公布了从南极洲乔治王岛沉积物样本中分离出的该属一种细菌的基因组草图序列（3,490,622 bp；18个支架；G + C = 42.76%）。通过系统发育分析、生化特性分析和扫描电子显微镜观察，该细菌被鉴定为BNF20，这使其成为该物种首个被报道的基因组序列。BNF20分别显示出对亚碲酸盐（最低抑菌浓度2.3 mM）和铬酸盐（最低抑菌浓度6.0 mM）的高抗性。全基因组核苷酸同一性比较表明BNF20与其他未鉴定的该属物种如JCM18903、JCM18902和P11F6高度相似（>90%）。贝叶斯多位点系统发育分析表明BNF20与从极地地区分离出的其他细菌属于一个多系分支。发现了大量与金属（类金属）抗性相关的基因，包括位于两个重叠群中的亚碲酸盐抗性遗传决定因素：重叠群LIQB01000002.1含有五个ter基因，每个基因都显示出假定的启动子序列（terACDEZ），而重叠群LIQB1000003.2显示出terZ基因的一个变体。最后，在NCBI的RefSeq细菌数据库（截至2017年1月有5,398个基因组）中研究ter基因的存在情况和分类分布，发现2,623个（48.59%）基因组至少含有一个ter基因。在科水平上，大多数（68.7%）基因组含有一个ter基因，15.6%的基因组含有五个（包括BNF20）。总体而言，我们的结果突出了该属的多样性本质（遗传和地理多样性），为金属抗性的潜在机制提供了见解，并例证了对偏远地区进行采样以探寻新分子决定因素的益处。
