Taxonomic Characterization, and Secondary Metabolite Analysis of Streptomyces triticiradicis sp. nov.: A Novel Actinomycete with Antifungal Activity

Abstract

The rhizosphere, an important battleground between beneficial microbes and pathogens, is usually considered to be a good source for isolation of antagonistic microorganisms. In this study, a novel actinobacteria with broad-spectrum antifungal activity, designated strain NEAU-H2T, was isolated from the rhizosphere soil of wheat (Triticum aestivum L.). 16S rRNA gene sequence similarity studies showed that strain NEAU-H2T belonged to the genus Streptomyces, with high sequence similarities to Streptomyces rhizosphaerihabitans NBRC 109807T (98.8%), Streptomyces populi A249T (98.6%), and Streptomyces siamensis NBRC 108799T (98.6%). Phylogenetic analysis based on 16S rRNA, atpD, gyrB, recA, rpoB, and trpB gene sequences showed that the strain formed a stable clade with S. populi A249T. Morphological and chemotaxonomic characteristics of the strain coincided with members of the genus Streptomyces. A combination of DNA–DNA hybridization results and phenotypic properties indicated that the strain could be distinguished from the abovementioned strains. Thus, strain NEAU-H2T belongs to a novel species in the genus Streptomyces, for which the name Streptomyces triticiradicis sp. nov. is proposed. In addition, the metabolites isolated from cultures of strain NEAU-H2T were characterized by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. One new compound and three known congeners were isolated. Further, genome analysis revealed that the strain harbored diverse biosynthetic potential, and one cluster showing 63% similarity to natamycin biosynthetic gene cluster may contribute to the antifungal activity. The type strain is NEAU-H2T (= CCTCC AA 2018031T = DSM 109825T).

Characterization of a Novel Endophytic Actinomycete, Streptomyces physcomitrii sp. nov., and Its Biocontrol Potential Against Ralstonia solanacearum on Tomato

“…The utilization of sole carbon and nitrogen sources was carried out, as described previously [ 25 ]. Other physiological and biochemical characteristics were conducted, according to a previous report [ 26 ].…”

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

“…Tolerance of pH range (pH 4-11, at intervals of 1 pH units), using buffer system described by Zhao et al [20] and NaCl tolerance (0-13%, with an interval of 1 %, w/v) for growth were determined after 2 weeks growth in ISP 2 broth in shake flasks (250 rpm) at 28 • C. The utilization of sole carbon and nitrogen sources at a final concentration of 0.5% (w/v) was tested using ISP 9 agar as the basal medium following the methods of Gordon et al [21]. Other physiological and biochemical characteristics were conducted based on a previous report [22].…”

“…The isomers of diaminopimelic acid (DAP) in the cell wall were derivatized according to McKerrow et al [23], and analyzed by a HPLC method using an Agilent TC-C18 Column (250 × 4.6 mm i.d. 5 µm) [22]. The whole-cell sugars were analyzed according to the procedures developed by Lechevalier and Lechevalier [24].…”

“…Phospholipids in cells were examined by two-dimensional TLC (thin-layer chromatography, Qingdao Marine Chemical Inc., Qingdao, China) and identified using the method of Minnikin et al [25]. Menaquinones were extracted from freeze-dried biomass and purified according to Collins [26] and analyzed by a HPLC-UV method as described previously [22]. Fatty acids were prepared and analyzed by GC-MS using the method of Zhuang et al [27].…”

Special Issue: “Actinobacteria and Myxobacteria—Important Resources for Novel Antibiotics”

“…This issue gathers 16 papers including 11 articles, 4 reviews and 1 communication. Six of them describe novel species or isolates and their characterization by the use of a polyphasic approach [ 7 , 8 , 9 , 10 , 11 , 12 ] as well as their secondary metabolites. Two of the articles describe Actinobacteria from uncommon habitats like the Western Ghats region in India [ 13 ] and endophytic ones [ 14 ].…”