Characterization of Streptomyces sporangiiformans sp. nov., a Novel Soil Actinomycete with Antibacterial Activity against Ralstonia solanacearum

Abstract

Ralstonia solanacearum is a major phytopathogenic bacterium that attacks many crops and other plants around the world. In this study, a novel actinomycete, designated strain NEAU-SSA 1T, which exhibited antibacterial activity against Ralstonia solanacearum, was isolated from soil collected from Mount Song and characterized using a polyphasic approach. Morphological and chemotaxonomic characteristics of the strain coincided with those of the genus Streptomyces. The 16S rRNA gene sequence analysis showed that the isolate was most closely related to Streptomyces aureoverticillatus JCM 4347T (97.9%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain formed a cluster with Streptomyces vastus JCM4524T (97.4%), S. cinereus DSM43033T (97.2%), S. xiangluensis NEAU-LA29T (97.1%) and S. flaveus JCM3035T (97.1%). The cell wall contained LL-diaminopimelic acid and the whole-cell hydrolysates were ribose, mannose and galactose. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), hydroxy-phosphatidylethanolamine (OH-PE), phosphatidylinositol (PI), two phosphatidylinositol mannosides (PIMs) and an unidentified phospholipid (PL). The menaquinones were MK-9(H4), MK-9(H6), and MK-9(H8). The major fatty acids were iso-C17:0, C16:0 and C17:1 ω9c. The DNA G+C content was 69.9 mol %. However, multilocus sequence analysis (MLSA) based on five other house-keeping genes (atpD, gyrB, recA, rpoB, and trpB), DNA–DNA relatedness, and physiological and biochemical data showed that the strain could be distinguished from its closest relatives. Therefore, it is proposed that strain NEAU-SSA 1T should be classified as representatives of a novel species of the genus Streptomyces, for which the name Streptomyces sporangiiformans sp. nov. is proposed. The type strain is NEAU-SSA 1T (=CCTCC AA 2017028T = DSM 105692T).

Rhodococcus oryzae sp. nov., a novel actinobacterium isolated from rhizosphere soil of rice (Oryza sativa L.)

“…Growth at different temperatures (4, 10, 15, 20, 28, 32, 35, 37, 40 and 45 °C) was determined on TSA after incubation for 7 days. The pH range for growth (pH 3.0-11.0, at intervals of 1.0 pH unit) [35] was determined in tryptic soybroth (TSB) medium and NaCl tolerance (0-12 % NaCl, w/v, with an interval of 1 % w/v) was determined in modified TSB medium without NaCl as the basal medium at 28 °C for 7 days on a rotary shaker. The utilization of sole carbon and nitrogen sources (0.5 % w/v), hydrolysis of aesculin and starch, decomposition of cellulose, reduction of nitrate, coagulation and peptonization of milk, liquefaction of gelatin and production of H 2 S were examined as described previously [36,37].…”

Streptomyces montanus sp. nov., a novel actinomycete isolated from soil

“…Spherical sporangia (4.5-4.9 µm) consisted of cylindrical and smooth spores were observed on ISP 3 medium ( Fig. 1) [3]. But strain NEAU-C151 T didn't produce aerial mycelium when it was cultured on ISP 1, ISP 2-7, Bennett's and Czapek's agar and nutrient agar media for two weeks.…”

“…The complex geographical topography of Mount Song promotes the formation of a unique ecological environment. Recently, several novel species of the genus Streptomyces were isolated from Mount Song by Zhao et al 2019 [3], which shows that such a unique habitat can be a promising source of the genus streptomyces. During our research into new actinobacterial resources, NEAU-C151 T was isolated from the soil which was collected from Mount Song, Dengfeng city, Henan province, China (34˚23′31′′N 112˚56′07′′E) and indicated to be a novel species of the genus Streptomyces from morphological, physiological and phylogenetic data.…”

“…Growth at different temperatures (10,15,20,25,28,32,35,37, 40 and 45 °C) was determined on ISP 3 medium after incubation for 14 days. Growth tests for pH range (pH 4.0-11.0, at intervals of 1.0 pH unit) using the buffer system as described previously [3,9] and NaCl tolerance (0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 %, w/v) were tested in Glucose-Yeast extract (GY) medium [10] at 28 °C for 14 days on a rotary shaker. The utilization of sole carbon and nitrogen sources (0.5 % w/v), decomposition of cellulose, hydrolysis of starch and aesculin, reduction of nitrate, coagulation and peptonization of milk, liquefaction of gelatin and production of H 2 S were examined as described previously [11,12].…”

Glycomyces albidus sp. nov., a novel actinobacterium isolated from rhizosphere soil of wheat (Triticum aestivum L.)

“…Growth at different temperatures (4,10,15,20,25,28,32,35,37,40,45 and 50 °C) was determined on ISP 4 medium after incubation for 14 days. The pH range for growth (pH 3.0-11.0, at intervals of 1.0 pH unit) was tested in glucose-yeast extract broth (GY) [15] using the buffer system described by Zhao et al [16]. Tolerance of various NaCl concentrations (0-10 %, with an interval of 1 %, w/v) was tested in GY medium.…”