School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, P. R. China.
J Microbiol. 2020 Feb;58(2):105-112. doi: 10.1007/s12275-020-9514-8. Epub 2020 Jan 29.
Two halophilic archaeal strains, SHR37 and NEN6, were isolated from salt lakes located in the Tibet and Xinjiang regions of China. The two strains were found to form a single cluster (99.9% and 99.3% similarity, respectively) separating them from the six current members of Natronorubrum (94.7-96.9% and 86.1-90.8% similarity, respectively) on the basis of the 16S rRNA and rpoB' gene sequence similarities and phylogenetic analysis. Diverse phenotypic characteristics differentiate strains SHR37 and NEN6 from current Natronorubrum members. Their polar lipids are CC and CCglycerol diether derivatives of PG, PGP-Me, and a major gycolipid chromatographically identical to disulfated mannosyl glucosyl diether (S-DGD). Four minor unidentified gycolipids are also present. The OrthoANI and in silico DDH values of the two strains were 97.3% and 76.1%, respectively, which were much higher than the threshold values proposed as a species boundary (ANI 95-96% and in silico DDH 70%), which revealed that the two strains represent one species; the two values (ANI 79.0-81.9% and in silico DDH 23.5-25.7%) of the strains examined in this study and the current members of Natronorubrum are much lower than the recommended threshold values, suggesting that strains SHR37 and NEN6 represent a genomically different species of Natronorubrum. These results showed that strains SHR37 (= CGMCC 1.15233 = JCM 30845) and NEN6 (= CGMCC 1.17161) represent a novel species of Natronorubrum, for which the name Natronorubrum halophilum sp. nov. is proposed.
两株嗜盐古菌 SHR37 和 NEN6 从中国西藏和新疆地区的盐湖中分离得到。基于 16S rRNA 和 rpoB' 基因序列相似性和系统发育分析，这两株菌与现有的六株嗜盐碱杆菌（Natronorubrum）聚为一簇（相似度分别为 99.9%和 99.3%），与现有嗜盐碱杆菌的相似度分别为 94.7-96.9%和 86.1-90.8%。株 SHR37 和 NEN6 的各种表型特征与现有的嗜盐碱杆菌成员不同。它们的极性脂是 CC 和 CC甘油二醚衍生的 PG、PGP-Me，以及一种主要的糖脂与二硫酸甘露糖葡萄糖基二醚（S-DGD）在色谱上相同。还存在四种未鉴定的糖脂。两株菌的 OrthoANI 和 in silico DDH 值分别为 97.3%和 76.1%，均远高于作为种间界限的推荐阈值（ANI 95-96%和 in silico DDH 70%），表明两株菌代表一个种；本研究中检测到的两株菌和现有的嗜盐碱杆菌的两株菌（ANI 79.0-81.9%和 in silico DDH 23.5-25.7%）的数值均远低于推荐的阈值，表明株 SHR37 和 NEN6 代表了嗜盐碱杆菌属的一个基因组不同的种。这些结果表明，株 SHR37（=CGMCC 1.15233=JCM 30845）和 NEN6（=CGMCC 1.17161）代表了嗜盐碱杆菌属的一个新种，提议将其命名为嗜盐碱杆菌嗜盐亚种。
