Streptomyces smaragdinus sp. nov., isolated from the gut of the fungus growing-termite Macrotermes natalensis

Abstract

The taxonomic position of a novel aerobic, Gram-positive actinobacteria, designated strain RB5T, was determined using a polyphasic approach. The strain, isolated from the gut of the fungus-farming termite Macrotermes natalensis, showed morphological, physiological and chemotaxonomic properties typical of the genus Streptomyces . Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbour of RB5T was Streptomyces polyrhachis DSM 42102T (98.87 %). DNA–DNA hybridization experiments between strain RB5T and S. polyrhachis DSM 42102T resulted in a value of 27.4 % (26.8 %). The cell wall of strain RB5T contained ll-diaminopimelic acid as the diagnostic amino acid. Mycolic acids and diagnostic sugars in whole-cell hydrolysates were not detected. The strain produced the following major phospholipids: diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol-mannoside and phosphatidylserine. The menaquinone profile showed hexa- and octahydrogenated menaquinones containing nine isoprene units [MK-9(H6) and MK-9(H8)]. The strain exhibited a fatty acid profile containing the following major fatty acids: 12-methyltridecanoic acid (iso-C14 : 0) 12-methyltetradecanoic acid (anteiso-C15 : 0), 13-methyltetradecanoic acid (iso-C15 : 0) and 14-methylpentadecanoic acid (iso-C16 : 0). Here, we propose a novel species of the genus Streptomyces – Streptomyces smaragdinus with the type strain RB5T (=VKM Ac-2839T=NRRL B65539T).

Comparative Genomics Reveals Prophylactic and Catabolic Capabilities of Actinobacteria within the Fungus-Farming Termite Symbiosis

“…Our addition of ARTS2 resulted in the identification of an additional 50 essential genes that pass the three-marker threshold, with one of those markers being close proximity to an identified BGC. This remarkable finding speaks for the high potential to identify not only new bacterial diversity ( 64 – 66 ) but also novel natural products. Further work on both gene expression and compound production within termite colonies as well as biochemical studies to characterize the underlying gene clusters and their products is needed to further elaborate the roles of Actinobacteria within the fungus-farming termite system.…”

Polyene-Producing Streptomyces spp. From the Fungus-Growing Termite Macrotermes barneyi Exhibit High Inhibitory Activity Against the Antagonistic Fungus Xylaria

“…Based on 16S rRNA sequence analysis, seven strains were predicted to be potential novel actinomycetes ( Supplementary Table 1 ). Recently, a number of new actinomycetes have been isolated and identified from the worker gut of M. natalensis ( Benndorf et al, 2020a , b ; Schwitalla et al, 2020 ). The intestinal microflora of fungus-growing termite represents a promising resource of novel actinomycetes.…”

Streptomyces: Still the Biggest Producer of New Natural Secondary Metabolites, a Current Perspective

“…They are beneficial for the insect microbiome because they influence the production of metabolites and the biosynthetic potential to inhibit and resist pathogens [99]. The main areas of insects that studies generally focus on are the intestinal region [100,101], the cuticle [102], and the head region [93,[103][104][105][106] (Table 3). Studies have shown that Streptomycetes live in symbiosis with insects and strengthen their defensive mechanism by producing chemicals for ecological adaptation [99].…”