Characterization of sp. nov. and Identification of the Putative Gene Cluster Encoding the Biosynthesis of Heliquinomycins.

A novel actinomycete producing heliquinomycin and 9'-methoxy-heliquinomycin, designated strain jys28, was isolated from rhizosphere soil of and characterized using a polyphasic approach. The strain had morphological characteristics and chemotaxonomic properties identical to those of members of the genus . It formed spiral chains of spores with spiny surfaces. The menaquinones detected were MK-9(H), MK-9(H) and MK-9(H). The major fatty acids were iso-C, C, Cω7с and anteiso-C. The phospholipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine and phosphatidylinositol mannoside. The DNA G + C content of the draft genome sequence, consisting of 8.5 Mbp, was 70.6%. Analysis of the 16S rRNA gene sequence showed that strain jys28 belongs to the genus with the highest sequence similarities to NBRC 13058 (99.2%) and DSM 40002 (99.2%) and phylogenetically clustered with them. Multilocus sequence analysis based on five other house-keeping genes (D, B, B, A and B and the low level of DNA-DNA relatedness and phenotypic differences allowed the novel isolate to be differentiated from its most closely related strains. Therefore, the strain is concluded to represent a novel species of the genus , for which the name sp. nov. is proposed. Furthermore, the putative biosynthetic gene cluster of heliquinomycins was identified and the biosynthetic pathway was discussed. The type strain is jys28 (=CCTCC AA 2018051 =DSM 109823).