Natural product biosynthesis in the genus Herpetosiphon : a genomics and chemistry-guided evaluation

A previous study revealed the presence of a diterpene synthase in H. aurantiacus DSM 785. Feeding experiments with isotope-labeled glucose led to the discovery of its possible metabolic product herpetopanone. In addition, chemical analysis allowed the discovery of five known products from Herpetosiphon spp. including two diketopiperazines, futalosine and its derivative, as well as N-acetyl-tryptophan. In order to increase species richness and reveal metabolic diverse of the genus Herpetosiphon, three unclassified Herpetosiphon spp. and a Herpetosiphon giganteus bacterium from DSMZ were subjected to a phylogenetic analysis. Based on phenotypic, chemotaxonomic and phylogenetic data it was concluded that Herpetosiphon sp. Hp g472 represents a novel species of the genus Herpetosiphon. In addition, an emended description of H. giganteus was proposed in this study. All bacteria in the genus Herpetosiphon are capable of predation. Genome mining of Herpetosiphon spp. revealed that they harbor a high number of biosynthetic gene clusters. Up to now, three new compounds were reported from the type species H. aurantiacus DSM 785, but the genomic potential for natural product biosynthesis is much larger. The phylum Chloroflexi is one of the deepest bacterial lineages and consists of species with various phenotypes and genotypes. Terpene synthases, especially phytoene synthases, are widely distributed in this phylum. In addition, Ktedonobacter racemifer from the genus Ktedonobacter has the ability to produce resistomycin analogs based on genome analysis.