Taxonomic analyses of members of the Streptomyces cinnabarinus cluster, description of Streptomyces cinnabarigriseus sp. nov. and Streptomyces davaonensis sp. nov.

Abstract

Roseoflavin is the only known riboflavin (vitamin B2) analog with antibiotic properties. It is actively taken up by many micro-organisms and targets flavinmononucleotide riboswitches and flavoproteins. It is described as the product of the tentatively named 'Streptomyces davawensis' JCM 4913. Taxonomic analysis of this strain with a polyphasic approach showed that it is very closely related to Streptomyces cinnabarinus (DSM 40467). The two Streptomyces isolates were obtained from different geographical locations (the Philippines and the Kamchatka Peninsula, respectively), their genomes have been sequenced and the question was whether or not the two isolates were representatives of the same species. As we also worked with another isolate of Streptomyces cinnabarinus JS 360, the producer of the cinnabaramides, we wanted to clarify the taxonomic position of the three isolates by using a polyphasic approach. After analysis of the 16S rRNA gene sequence, we found in total 23 species of the genus Streptomyces that showed a similarity higher than 98.5 % to the three strains. We showed that 'S. davawensis' JCM 4913 and S. cinnabarinus DSM 40467 were very closely related but belong to two different species. Hence, we validate 'S. davawensis' as Streptomyces davaonensis sp. nov. with the type strain JCM 4913 (=DSM 101723). In addition, the cinnabaramide producer can be clearly differentiated from S. davaonensis and this isolate is described as Streptomyces cinnabarigriseus sp. nov. with strain JS360 (=NCCB 100590=DSM 101724) as the type strain.

The roseoflavin producer Streptomyces davaonensis has a high catalytic capacity and specific genetic adaptations with regard to the biosynthesis of riboflavin

“…The Gram‐positive bacteria Streptomyces davaonensis (formerly Streptomyces davawensis ) and Streptomyces cinnabarinus are the only organisms known to produce the antibiotic roseoflavin (Fig. 1), a riboflavin (vitamin B 2 ) analogue (Otani et al ., 1974; Jankowitsch et al ., 2012; Landwehr et al ., 2018). All bacteria able to take up roseoflavin are likely to be sensitive to this antibiotic (Hemberger et al ., 2011; Pedrolli et al ., 2013; Pedrolli et al ., 2014; Matern et al ., 2016).…”

The novel phosphatase RosC catalyzes the last unknown step of roseoflavin biosynthesis in Streptomyces davaonensis

“…Roseoflavin (RoF) is a red riboflavin analog with broad antimicrobial activity against Gram‐positive bacteria (Otani et al ., 1974). Under laboratory conditions RoF is produced in the stationary phase of growth by two different Gram‐positive bacterial species, S. davaonensis (formerly S. davawensis (Landwehr et al ., 2018)) and Streptomyces cinnabarinus (Jankowitsch et al ., 2012). Other RoF producers are not known.…”

Metabolic engineering of roseoflavin-overproducing microorganisms

“…The Gram-positive bacteria Streptomyces davaonensis (formerly known as Streptomyces davawensis ) and Streptomyces cinnabarinus naturally produce roseoflavin and most likely actively secrete it employing a flavin exporter [13–15]. These filamentous bacteria typically grow as cell aggregates which adhere to the surfaces of culture vessels making difficult their culturing and processing of their metabolites.…”