Nocardioides aquaticus KCTC 9944^T is an aerobic, non-motile, Gram-positive, psychrotolerant, non-spore-forming bacterium isolated from the surface water of Ekho Lake in the Vestfold Hills, East Antarctica. This meromictic lake separated from Antarctic seawater thousands of years ago exhibits steep gradients of salinity and temperature in the upper layer of the water column. The cells of N. aquaticus thriving in Ekho Lake are able to grow in wide ranges of temperature (3 to 43.5 °C) and salinity (0 to 15% NaCl). Here, we sequenced the complete genome of N. aquaticus KCTC 9944^T, aiming to better understand the adaptation of this bacterium to the strong environmental gradients at the molecular level. The genome consists of 4,580,814 bp (G + C content of 73.2%) with a single chromosome, 4432 protein-coding genes, 51 tRNAs and 2 rRNA operons. The genome possesses genes for the Entner-Doudoroff pathway, photoheterotrophy, the conversion of acetate to acetyl-CoA, gluconeogenesis, and energy storage that are all advantageous to oligotrophic bacteria. The presence of genes involved in osmotic balance, fatty acid desaturation, cold and heat shock responses, and the oxygen affinities of respiratory oxidases are likely associated with high tolerance to strong gradients of salinity, temperature and oxygen concentration.

水生诺卡氏菌KCTC 9944 ^T是一种需氧、不运动、革兰氏阳性、耐寒、不形成孢子的细菌，从南极洲东部 Vestfold 山的 Ekho 湖的地表水中分离出来。这个数千年前与南极海水分离的meromictic湖在水柱的上层表现出陡峭的盐度和温度梯度。在 Ekho 湖中茁壮成长的水生猪笼草的细胞能够在广泛的温度（3 至 43.5 °C）和盐度（0 至 15% NaCl）范围内生长。在这里，我们对水生猪笼草KCTC 9944 ^T的完整基因组进行了测序，旨在更好地了解这种细菌在分子水平上对强环境梯度的适应。基因组由 4,580,814 bp（G + C 含量为 73.2%）组成，具有单个染色体、4432 个蛋白质编码基因、51 个 tRNA 和 2 个 rRNA 操纵子。基因组拥有 Entner-Doudoroff 途径、光异养、乙酸盐转化为乙酰辅酶 A、糖异生和能量储存的基因，这些基因都对贫营养细菌有利。涉及渗透平衡、脂肪酸去饱和、冷和热休克反应以及呼吸氧化酶的氧亲和力的基因的存在可能与对盐度、温度和氧浓度的强梯度的高耐受性有关。