Huang Tao, Fu Jia-Cheng, Dong Shuo-Han, Zhang Qiu-Mei, Wu Ting-Ting, Qiu Li-Hong
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
Int J Syst Evol Microbiol. 2021 Sep;71(9). doi: 10.1099/ijsem.0.004985.
Cells of bacterial strains G9 and 7MK23, isolated from forest soil samples collected from the Dinghushan Biosphere Reserve, Guangdong Province, PR China, were Gram-stain-negative, aerobic and rod-shaped. Strain G9 was motile with single polar flagellum and grew at 12-37 °C (optimum, 28 °C), pH 4.5-8.0 (optimum, pH 6.0-7.5) and in the presence of 0-3.5 % NaCl (optimum, 1.5%, w/v); while strain 7MK23 was non-motile and grew at 12-42 °C (optimum, 28-33 °C), pH 2.5-8.5 (optimum, pH 4.5-6.5) and NaCl levels of 0-1.0 % (optimum, 0-0.5 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequences revealed that both isolates fell within the cluster of the genus . The closely related species (with a 16S rRNA gene sequence similarity >98.65%) of strain G9 were JS14-6 (99.0 %), . THG-B117 (98.8 %) and . DHC06 (98.7 %) while that of strain 7MK23 were . DHON07 (99.2 %) and . DHOC52 (99.1 %), but the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strains G9, 7MK23 and the closely related species listed above were in the ranges of 77.5-83.8 % and 22.0-27.0 %, much lower than the species demarcation lines of 95.5 and 70 %, respectively. Phylogenomic analyses using UBCG and Phylophlan also supported that these two strains represent two novel species of . The major fatty acids of strain G9 were iso-C, iso-C 9 and iso-C while that of strain 7MK23 were iso-C and anteiso-C. Ubiquinone-8 was the only respiratory quinone detected in both strains. The polar lipids of strain G9 consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and several unknown phospholipids, aminophospholipids, aminolipids and lipid while strain 7MK23 contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine and several unknown phospholipids and aminophospholipids. The DNA G+C contents of strains G9 and 7MK23 were 64.7 and 63.4 mol%, respectively. On the basis of 16S rRNA gene sequence phylogenetic and phylogenomic analyses as well as phenotypic data obtained, we propose that strains G9 and 7MK23 represent two novel species of the genus , for which the names sp. nov. (type strain G9=KACC 21725=GDMCC 1.2132) and sp. nov. (type strain 7MK23=KCTC 62739=GDMCC 1.1446) are proposed.
从中国广东省鼎湖山生物圈保护区采集的森林土壤样本中分离出的细菌菌株G9和7MK23的细胞，革兰氏染色阴性，好氧，杆状。菌株G9具单极鞭毛，可运动，在12 - 37 °C（最适温度28 °C）、pH 4.5 - 8.0（最适pH 6.0 - 7.5）以及0 - 3.5%（最适1.5%，w/v）NaCl条件下生长；而菌株7MK23不运动，在12 - 42 °C（最适温度28 - 33 °C）、pH 2.5 - 8.5（最适pH 4.5 - 6.5）以及0 - 1.0%（最适0 - 0.5%，w/v）NaCl水平下生长。基于16S rRNA基因序列的系统发育分析表明，这两个分离株均属于该属的聚类。菌株G9的密切相关物种（16S rRNA基因序列相似性>98.65%）为JS14 - 6（99.0%）、THG - B117（98.8%）和DHC06（98.7%），而菌株7MK23的密切相关物种为DHON07（99.2%）和DHOC52（99.1%），但菌株G9、7MK23与上述密切相关物种之间的平均核苷酸同一性（ANI）和数字DNA - DNA杂交（dDDH）值分别在77.5 - 83.8%和22.0 - 27.0%范围内，远低于95.5和70%的物种划分界限。使用UBCG和Phylophlan进行的系统基因组分析也支持这两个菌株代表该属的两个新物种。菌株G9的主要脂肪酸为异C、异C9和异C，而菌株7MK23的主要脂肪酸为异C和anteiso - C。泛醌 - 8是在这两个菌株中检测到的唯一呼吸醌。菌株G9的极性脂质由磷脂酰甘油、双磷脂酰甘油、磷脂酰乙醇胺以及几种未知的磷脂、氨基磷脂、氨基脂质和脂质组成，而菌株7MK23含有磷脂酰甘油、双磷脂酰甘油、磷脂酰乙醇胺、磷脂酰甲基乙醇胺以及几种未知的磷脂和氨基磷脂。菌株G9和7MK23的DNA G + C含量分别为64.7和63.4 mol%。基于16S rRNA基因序列系统发育和系统基因组分析以及获得的表型数据，我们提议菌株G9和7MK23代表该属的两个新物种，分别命名为sp. nov.（模式菌株G9 = KACC 21725 = GDMCC 1.2132）和sp. nov.（模式菌株7MK23 = KCTC 62739 = GDMCC 1.
