Muangham Supattra, Duangmal Kannika
Department of Microbiology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, Thailand.
Biodiversity Center Kasetsart University (BDCKU), Bangkok, Thailand.
J Antibiot (Tokyo). 2021 Dec;74(12):856-862. doi: 10.1038/s41429-021-00470-x. Epub 2021 Sep 6.
An endophytic actinomycete, designated strain RL4-1S, was isolated from surface-sterilized leaves of rice plant (Oryza sativa L.) collected from Buri Rum province, Thailand. Its taxonomic status was determined using a polyphasic approach. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the strain RL4-1S belongs to the genus Microbispora and is most closely related to Microbispora rosea subsp. rosea ATCC 12950 (98.5%). The strain forms pairs of spores on short sporophores borne on the aerial mycelium. Polar lipid profile of strain RL4-1S is diphosphatidylglycerol, hydroxy-phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, ninhydrin-positive glycophospholipid, two unidentified phospholipids, an unidentified aminolipid, and an unidentified glycolipid. MK-9(H), MK-9(H), and MK-9 are major menaquinones of this organism. The predominant cellular fatty acids are iso-C, C and C. Strain RL4-1S contains meso-diaminopimelic acid, glucose, madurose and ribose in whole-cell hydrolysates. The draft genome of strain RL4-1S consists of 7.46 Mbp and has a G + C content 71.2 mol%. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain RL4-1S with Microbispora rosea subsp. rosea ATCC 12950 are 26.0% and 80.7%, respectively. Based on data of genotypic, phenotypic, phylogenetic and chemotaxonomic analysis, strain RL4-1S represents a novel species of the genus Microbispora, for which the name Microbispora oryzae sp. nov. is proposed. The type strain is RL4-1S (= TBRC 14817 = NBRC 115115).
从泰国武里南府采集的经表面消毒的水稻植株（Oryza sativa L.）叶片中分离出一株内生放线菌，命名为RL4-1S菌株。采用多相分类法确定其分类地位。基于16S rRNA基因序列的系统发育分析表明，RL4-1S菌株属于小双孢菌属，与玫瑰小双孢菌玫瑰亚种ATCC 12950关系最为密切（相似度为98.5%）。该菌株在气生菌丝上的短孢子梗上形成成对的孢子。RL4-1S菌株的极性脂质组成为双磷脂酰甘油、羟基磷脂酰乙醇胺、磷脂酰乙醇胺、磷脂酰肌醇、磷脂酰肌醇甘露糖苷、茚三酮阳性糖脂、两种未鉴定的磷脂、一种未鉴定的氨基脂和一种未鉴定的糖脂。MK-9(H)、MK-9(H)和MK-9是该菌株的主要甲基萘醌。主要的细胞脂肪酸为异-C、C和C。RL4-1S菌株的全细胞水解产物中含有内消旋二氨基庚二酸、葡萄糖、马杜拉糖和核糖。RL4-1S菌株的基因组草图由7.46 Mbp组成，G+C含量为71.2 mol%。RL4-1S菌株与玫瑰小双孢菌玫瑰亚种ATCC 12950的基因组序列之间的数字DNA-DNA杂交值和平均核苷酸同一性值分别为26.0%和80.7%。基于基因型、表型、系统发育和化学分类分析数据，RL4-1S菌株代表小双孢菌属的一个新物种，为此提出新名称水稻小双孢菌（Microbispora oryzae sp. nov.）。模式菌株为RL4-1S（=TBRC 14817=NBRC 115115）。
