Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, PR China.
Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, PR China.
Int J Syst Evol Microbiol. 2020 Jun;70(6):3801-3808. doi: 10.1099/ijsem.0.004234. Epub 2020 May 27.
Six Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and motile strains (FT9W, FT25W, FT26W, FT109W, FT134W and CY42W) were isolated from subtropical streams in China. Comparisons based on 16S rRNA gene sequences showed that the six strains shared similarities of less than 98.1 % with other species within the family and formed two separately distinct clades in phylogenetic trees. The 16S rRNA gene sequence similarities between strains FT9W and FT25W, and between strains FT109W and FT134W were both 99.7 %. The genome sizes of strains FT9W, FT25W, FT26W, FT109W, FT134W and CY42W were 6.45, 6.45, 6.54, 6.43, 6.52 and 6.74 Mbp with G+C contents of 64.0, 64.0, 63.8, 63.2, 63.2 and 62.5 %, respectively. The calculated pairwise average nucleotide (ANI) values among the six strains and other related species were less than 93.9 %, except that the values were 99.9 % between strains FT9W and FT25W, 98.2 % between strains FT109W and FT134W, and 95.0 and 95.1 % between strain FT26W and strains FT9W and FT25W, respectively. However, strain FT26W shared 16S rRNA gene sequence similarities of only 98.3 and 98.2 % with FT9W and FT25W, respectively. The respiratory quinone of the six strains was determined to be Q-8. The major fatty acids were C7, C and C. The predominant polar lipids included phosphatidylethanolamine and phosphatidylglycerol. Considering the phenotypic, biochemical, genotypic and ANI data, strains FT9W and FT25W, and FT109W and FT134W may belong to the same species, respectively. Although the pairwise ANI values between strain FT26W and each of strains FT9W and FT25W were located in the transition region of species demarcation, the dissimilarities among them indicated that strain FT26W could represent an independent novel species. The reconstructed phylogenomic tree based on a concatenation of 92 core genes showed that the six strains clustered closely with Sac-22 and KCTC 22382, and supported that these six strains belong to the genus . The names sp. nov. (type strain FT9W=GDMCC 1.1637=KACC 21313), sp. nov. (type strain FT26W=GDMCC 1.1641=KACC 21315), sp. nov. (type strain FT109W=GDMCC 1.1688=KACC 21480) and sp. nov. (type strain CY42W=GDMCC 1.1673=KACC 21465) are proposed.
从中国亚热带溪流中分离到六株革兰氏阴性、接触酶和氧化酶阳性、杆状和运动的菌株（FT9W、FT25W、FT26W、FT109W、FT134W 和 CY42W）。基于 16S rRNA 基因序列的比较表明，这六株菌与科内其他种的相似性均低于 98.1%，并在系统发育树中形成两个独立的分支。菌株 FT9W 和 FT25W 之间以及菌株 FT109W 和 FT134W 之间的 16S rRNA 基因序列相似性均为 99.7%。菌株 FT9W、FT25W、FT26W、FT109W、FT134W 和 CY42W 的基因组大小分别为 6.45、6.45、6.54、6.43、6.52 和 6.74 Mbp，G+C 含量分别为 64.0、64.0、63.8、63.2、63.2 和 62.5%。这六株菌与其他相关种之间的计算成对平均核苷酸（ANI）值均小于 93.9%，除了菌株 FT9W 和 FT25W 之间的数值为 99.9%、菌株 FT109W 和 FT134W 之间的数值为 98.2%、菌株 FT26W 与菌株 FT9W 和 FT25W 之间的数值分别为 95.0%和 95.1%。然而，菌株 FT26W 与 FT9W 和 FT25W 的 16S rRNA 基因序列相似性分别仅为 98.3%和 98.2%。这六株菌的呼吸醌均为 Q-8。主要脂肪酸为 C7、C 和 C。主要极性脂包括磷脂酰乙醇胺和磷脂酰甘油。考虑到表型、生化、基因型和 ANI 数据，菌株 FT9W 和 FT25W 以及 FT109W 和 FT134W 可能分别属于同一物种。尽管菌株 FT26W 与菌株 FT9W 和 FT25W 之间的两两 ANI 值位于种的划分的过渡区，但它们之间的差异表明菌株 FT26W 可能代表一个独立的新种。基于 92 个核心基因的连接体构建的系统发育基因组树表明，这六株菌与 Sac-22 和 KCTC 22382 聚类紧密，支持这六株菌属于 Sac-22 属。因此，提出了六个新种的命名，即 sp. nov.（命名为 FT9W=GDMCC 1.1637=KACC 21313 的模式菌株）、sp. nov.（命名为 FT26W=GDMCC 1.1641=KACC 21315 的模式菌株）、sp. nov.（命名为 FT109W=GDMCC 1.1688=KACC 21480 的模式菌株）和 sp. nov.（命名为 CY42W=GDMCC 1.1673=KACC 21465 的模式菌株）。
