Wen Ying, Li Jiahui, Qiao Fujun, Luo Wanyin, Chen Tuo, Liu Guangxiu, Zhang Wei
State Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
Microorganisms. 2025 Jul 10;13(7):1628. doi: 10.3390/microorganisms13071628.
A novel actinobacterial strain, designated E54, was isolated from a hyper-arid desert soil sample collected from the Kumtagh Desert in Dunhuang, Gansu Province, China. Phylogenetic analysis based on 16S rRNA gene sequences placed strain E54 within the genus , showing highest similarity to DSM 44232 (98.9%) and NBRC 15743 (98.5%). However, whole-genome comparisons revealed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between E54 and these related strains were below the thresholds for species delineation. Strain E54 exhibited typical morphological characteristics of the genus , forming a branched substrate. It grew optimally at 28-30 °C, pH 7.0-9.0, and tolerated up to 10% NaCl. The cell wall contained meso-diaminopimelic acid, the predominant menaquinone was MK-9(H), and major fatty acids included iso-C. The polar lipid profile comprised diphosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl inositol, hydroxyphosphatidyl ethanolamine, and an unidentified lipid. The characteristic amino acid type of the cell wall was meso-DAP. Whole-cell hydrolysis experiments revealed the characteristic cell wall sugar fractions: ribose and galactose. The genome of strain E54 is approximately 8.0 Mb with a DNA G+C content of 69.38 mol%. Genome mining revealed 39 biosynthetic gene clusters (BGCs), including non-ribosomal peptide synthetases (NRPS), polyketide synthases (PKS), terpenes, and siderophores. Comparative antiSMASH-based genome analysis across 38 strains further demonstrated the genus' remarkable biosynthetic diversity. NRPS and type I PKS (T1PKS) were the most prevalent BGC types, indicating a capacity to synthesize structurally complex and pharmacologically relevant metabolites. Together, these findings underscore the untapped biosynthetic potential of the genus and support the proposal of strain E54 as a novel species. The strain E54 (=JCM 34936 = GDMCC 4.216) should represent a novel species, for which the name sp. nov. is proposed.
从中国甘肃省敦煌库姆塔格沙漠采集的高干旱沙漠土壤样本中分离出一株新型放线菌菌株，命名为E54。基于16S rRNA基因序列的系统发育分析将菌株E54归入该属，与DSM 44232（98.9%）和NBRC 15743（98.5%）的相似性最高。然而，全基因组比较显示，E54与这些相关菌株之间的平均核苷酸同一性（ANI）和数字DNA-DNA杂交（dDDH）值低于物种划分的阈值。菌株E54表现出该属典型的形态特征，形成分支状基质。它在28-30℃、pH 7.0-9.0条件下生长最佳，可耐受高达10%的NaCl。细胞壁含有内消旋二氨基庚二酸，主要的甲基萘醌是MK-9(H)，主要脂肪酸包括异-C。极性脂质谱包括双磷脂酰甘油、磷脂酰乙醇胺、磷脂酰肌醇、羟基磷脂酰乙醇胺和一种未鉴定的脂质。细胞壁的特征氨基酸类型是内消旋-DAP。全细胞水解实验揭示了特征性的细胞壁糖组分：核糖和半乳糖。菌株E54的基因组约为8.0 Mb，DNA G+C含量为69.38 mol%。基因组挖掘发现了39个生物合成基因簇（BGCs），包括非核糖体肽合成酶（NRPS）、聚酮合酶（PKS）、萜类和铁载体。基于antiSMASH对38个该属菌株进行的全基因组比较分析进一步证明了该属具有显著的生物合成多样性。NRPS和I型PKS（T1PKS）是最普遍的BGC类型，表明其具有合成结构复杂且与药理相关代谢物的能力。总之，这些发现强调了该属尚未开发的生物合成潜力，并支持将菌株E54作为一个新物种的提议。菌株E54（=JCM 34936 = GDMCC 4.216）应代表一个新物种，为此提议命名为新种。
