Actinomadura rubteroloni sp. nov. and Actinomadura macrotermitis sp. nov., isolated from the gut of the fungus growing-termite Macrotermes natalensis

The taxonomic positions of two novel aerobic, Gram-positive actinobacteria, designated strains RB29$^{T}$ and RB68T, were determined using a polyphasic approach. Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbours of RB29$^{T}$ were identified as Actinomadura rayongensis DSM 102126$^{T}$ (99.2 % similarity) and Actinomadura atramentaria DSM 43919$^{T}$ (98.7 %), and for strain RB68$^{T}$ was Actinomadura hibisca DSM 44148$^{T}$ (98.3 %). Digital DNA–DNA hybridization (dDDH) between RB29$^{T}$ and its closest phylogenetic neighbours, A. rayongensis DSM 102126$^{T}$ and A. atramentaria DSM 43919$^{T}$, resulted in similarity values of 53.2 % (50.6–55.9 %) and 26.4 % (24.1–28.9 %), respectively. Additionally, the average nucleotide identity (ANI) was 93.2 % (94.0 %) for A. rayongensis DSM 102126$^{T}$ and 82.3 % (78.9 %) for A. atramentaria DSM 43919$^{T}$. dDDH analysis between strain RB68$^{T}$ and A. hibisca DSM 44148$^{T}$ gave a similarity value of 24.5 % (22.2–27.0 %). Both strains, RB29$^{T}$ and RB68$^{T}$, revealed morphological characteristics and chemotaxonomic features typical for the genus Actinomadura, such as the presence of meso-diaminopimelic acid in the cell wall, galactose and glucose as major sugar components within whole-cell hydrolysates and the absence of mycolic acids. ... mehrThe major phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. Predominant menaquinones were MK-9(H$_{6}$) and MK-9(H$_{8}$) for RB29$^{T}$ and MK-9(H$_{4}$) and MK-9(H$_{6}$) for RB68T. The main fatty acids were identified as 10-methyloctadecanoic acid (10-methyl C$_{18:0}$), 14-methylpentadecanoic acid (iso-C$_{16:0}$), hexadecanoic acid (C$_{16:0}$) and cis-9-octadecanoic acid (C$_{18:1}$ ω9c). Here, we propose two novel species of the genus Actinomadura: Actinomadura rubteroloni sp. nov. with the type strain RB29$^{T}$ (=CCUG 72668$^{T}$=NRRL B-65537$^{T}$) and Actinomadura macrotermitis sp. nov. with the type strain RB68$^{T}$ (=CCUG 72669$^{T}$=NRRL B-65538$^{T}$).