Niemhom Nantawan, Chutrakul Chanikul, Suriyachadkun Chanwit, Tadtong Sarin, Thawai Chitti
1Department of Biology, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
2Bioassay Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand.
Int J Syst Evol Microbiol. 2019 Feb;69(2):454-459. doi: 10.1099/ijsem.0.003175. Epub 2018 Dec 17.
An endophytic actinobacterium, designated strain KE2-3, was isolated from surface-sterilised rhizome of Kaempferia elegans. The polyphasic approach was used for evaluating the taxonomic position of this strain. The taxonomic affiliation of this strain at genus level could be confirmed by its chemotaxonomic characteristic, i.e. the presence of ll-diaminopimelic acid in the cell peptidoglycan, MK-9(H4) as the major menaquinone, iso-C16 : 0, anteiso-C15 : 0, iso-C14 : 0 and iso-C15 : 0 as the predominant fatty acids in cells, and the presence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside in its membranes. Based on 16S rRNA gene sequence analysis, strain KE2-3 was identified as a member of the genus Jiangella and showed the highest similarities to Jiangella muralis DSM 45357 (99.3 %) followed by Jiangella albaDSM 45237 (99.2 %), Jiangella alkaliphilia DSM 45079 (99.0 %), Jiangella gansuensisDSM 44835 (98.8 %) and Jiangella mangrovi3SM4-07 (98.6 %). However, the draft genome sequence of strain KE2-3 exhibited low average nucleotide identity values to the reference strains (85.5-90.2 %), which were well below the 95-96 % species circumscription threshold. The DNA G+C content of genomic DNA was 72.3 mol%. With the differences of physiological, biochemical and genotypic data, strain KE2-3 could be discriminated from its closest neighbour. Thus, strain KE2-3 should be recognised as a novel species of genus Jiangella, for which the name Jiangellaendophytica sp. nov. is proposed. The type strain is KE2-3 (=BCC 66359=NBRC 110004).
从艳山姜表面消毒的根茎中分离出一株内生放线菌，命名为KE2-3菌株。采用多相分类法评估该菌株的分类地位。该菌株在属水平上的分类归属可通过其化学分类特征来确定，即细胞肽聚糖中存在ll-二氨基庚二酸，MK-9(H4)作为主要甲基萘醌，异-C16 : 0、anteiso-C15 : 0、异-C14 : 0和异-C15 : 0作为细胞中的主要脂肪酸，以及其细胞膜中存在双磷脂酰甘油、磷脂酰甘油、磷脂酰肌醇和磷脂酰肌醇甘露糖苷。基于16S rRNA基因序列分析，KE2-3菌株被鉴定为Jiangella属的成员，与Jiangella muralis DSM 45357的相似性最高（99.3 %），其次是Jiangella alba DSM 45237（99.2 %）、Jiangella alkaliphilia DSM 45079（99.0 %）、Jiangella gansuensis DSM 44835（98.8 %）和Jiangella mangrovi 3SM-07（98.6 %）。然而，KE2-3菌株的基因组草图序列与参考菌株的平均核苷酸同一性值较低（85.5-90.2 %），远低于95-96 %的物种界定阈值。基因组DNA的DNA G+C含量为72.3 mol%。由于生理、生化和基因型数据的差异，KE2-3菌株可与其最接近的亲缘种区分开来。因此，KE2-3菌株应被认定为Jiangella属的一个新物种，为此提出新名称Jiangella endophytica sp. nov.。模式菌株为KE2-3（=BCC 66359=NBRC 110004）。
