Powdered Chitin Agar as a Selective Medium for Enumeration of Actinomycetes in Water and Soil

Sheu

International Journal of Systematic and Evolutionary Microbiology

et al. 2012

A bacterial strain, isolated from a sample of reef-building coral (Isopora palifera) collected off the coast of southern Taiwan, was characterized using a polyphasic taxonomic approach. The strain, designated sw-2T, was Gram-staining-negative, aerobic, rod-shaped and motile, with subpolar flagella, and formed greyish pink colonies. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain sw-2T was most closely related to Roseivivax halodurans Och 239T (97.4 % sequence similarity) and Roseivivax halotolerans Och 210T (96.4 %). The novel strain did not require NaCl for growth and exhibited optimal growth at 35–40 °C, at pH 7.5–8.0 and with 3–7 % (w/v) NaCl. It produced bacteriochlorophyll a under aerobic conditions. Summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 63.7 %) predominated in the cellular fatty acid profile. The novel strain’s major respiratory quinone was ubiquinone Q-10 and its genomic DNA G+C content was 68.8 mol%. The polar lipid profile consisted of a mixture of phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol, phosphatidyldimethylethanolamine, sulfo-quinovosyl diacylglycerol and three uncharacterized phospholipids. The level of DNA–DNA relatedness between strain sw-2T and Roseivivax halodurans Och 239T was only 15.0 %. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of the novel strain from all established species of the genus Roseivivax . Based on the genotypic, phenotypic and chemotaxonomic data, strain sw-2T represents a novel species in the genus Roseivivax , for which the name Roseivivax isoporae sp. nov. is proposed. The type strain is sw-2T ( = LMG 25204T = BCRC 17966T).

mentioning

confidence: 99%

Roseivivax isoporae sp. nov., isolated from a reef-building coral, and emended description of the genus Roseivivax

Sheu

International Journal of Systematic and Evolutionary Microbiology

et al. 2012

“…Hydrolysis of carboxymethylcellulose was tested as described by Bowman (2000), using MA as the basal medium. Hydrolysis of chitin was tested using agar medium supplemented with 0.2 % (w/v) colloidal chitin (Hsu & Lockwood, 1975). API 20NE, API 20E, API ZYM (bioMérieux) and GN2 MicroPlate (Biolog) microtest systems were used to determine the biochemical properties, enzyme activities and carbohydrate utilization pattern of strain SW15 T .…”

mentioning

confidence: 99%

Idiomarina aquimaris sp. nov., isolated from the reef-building coral Isopora palifera

Sheu

International Journal of Systematic and Evolutionary Microbiology

et al. 2012

A bacterial strain designated SW15T was isolated from a sample of the reef-building coral Isopora palifera, collected in southern Taiwan. The novel strain was characterized using a polyphasic taxonomic approach. Cells of strain SW15 T were Gram-negative, aerobic, light yellow, rod-shaped and motile by means of a single polar flagellum. In phylogenetic analyses based on 16S rRNA gene sequences, strain SW15 T appeared to belong to the genus Idiomarina in the class Gammaproteobacteria and to be most closely related to Idiomarina homiensis PO-M2 T (97.6 % sequence similarity). Strain SW15 T exhibited optimal growth between 20 and 30 6C, with NaCl between 3 % and 4 % (w/v) and at a pH value between 7 and 8. Predominant cellular fatty acids were iso-C 15 : 0 (31.1 %), iso-C 17 : 0 (15.4 %), iso-C 17 : 1 v9c (10.0 %) and C 16 : 0 (8.8 %). The major respiratory quinone was ubiquinone Q-8. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylserine, an uncharacterized aminolipid and several uncharacterized phospholipids. The DNA G+C content was 51.1 mol%.

“…Chitinase activity : Colloidal chitin amended medium (CCA) [ 95 ] was prepared to screen the ability of isobacterial lates to produce chitinase. The medium consisted of (g/L): Na2HPO4, 2; KH2PO4, 1; NH4Cl, 1; NaCl, 0.5; MgSO4 7H2O, 0.5; CaCl2 2H2O, 0.5; yeast extract, 0.5; agar, 15 and 5 g colloidal chitin [ 96 ].…”

Section: Methodsmentioning

confidence: 99%

Potential Role of Rhizobacteria Isolated from Citrus Rhizosphere for Biological Control of Citrus Dry Root Rot

Ezrari

Mhidra

Radouane

et al. 2021

Plants

Citrus trees face threats from several diseases that affect its production, in particular dry root rot (DRR). DRR is a multifactorial disease mainly attributed to Neocosmospora (Fusarium) solani and other several species of Neocosmospora and Fusarium spp. Nowadays, biological control holds a promising control strategy that showed its great potential as a reliable eco-friendly method for managing DRR disease. In the present study, antagonist rhizobacteria isolates were screened based on in vitro dual culture bioassay with N. solani. Out of 210 bacterial isolates collected from citrus rhizosphere, twenty isolates were selected and identified to the species level based on the 16S rRNA gene. Molecular identification based on 16S rRNA gene revealed nine species belonging to Bacillus, Stenotrophomonas, and Sphingobacterium genus. In addition, their possible mechanisms involved in biocontrol and plant growth promoting traits were also investigated. Results showed that pectinase, cellulose, and chitinase were produced by eighteen, sixteen, and eight bacterial isolates, respectively. All twenty isolates were able to produce amylase and protease, only four isolates produced hydrogen cyanide, fourteen isolates have solubilized tricalcium phosphate, and ten had the ability to produce indole-3-acetic acid (IAA). Surprisingly, antagonist bacteria differed substantially in their ability to produce antimicrobial substances such as bacillomycin (five isolates), iturin (ten isolates), fengycin (six isolates), surfactin (fourteen isolates), and bacteriocin (subtilosin A (six isolates)). Regarding the PGPR capabilities, an increase in the growth of the bacterial treated canola plants, used as a model plant, was observed. Interestingly, both bacterial isolates Bacillus subtilis K4-4 and GH3-8 appear to be more promising as biocontrol agents, since they completely suppressed the disease in greenhouse trials. Moreover, these antagonist bacteria could be used as bio-fertilizer for sustainable agriculture.