Growth promotion of chickpea and barley by a phosphate solubilizing strain of Mesorhizobium mediterraneum under growth chamber conditions

Actinomycetes are widely distributed in different habitats and involved in important processes. Therefore, evaluation of their distribution is important in understanding their ecological role. Ninety seven samples were taken from different soil ecosystems (forest, pasture, rain-fed and irrigated cultivated land) located in various climatic zones in the province of Golestan, Northeast Iran. The number of actinomycetes as well as pH value, organic carbon (OC) and soil salinity expressed as electrical conductivity (EC) showed significant differences in the soil ecosystems under investigation. The number of actinomycetes decreased from 2.86 * 10 6 cfu g -1 in irrigated cultivated land to 7* 10 5 cfu g -1 in pasture (p<0.01). In pastures, the number of actinomycetes was negatively correlated with EC (r=-0.60, n=15, p<0.001) and pH (r=-0.59, n=15, p<0.001). In other soil ecosystems under investigation no significant correlations between soil pH, OC and EC and the number of actinomycetes could be found. In forest soils, the number of actinomycetes was significantly dependent (p<0.05) on climate. A significantly higher population was observed under semi-arid conditions compared to all other climatic zones (humid, sub-humid, Mediterranean). Because many soil microorganisms are able to transform different forms of insoluble organic and inorganic phosphorus into a soluble form suitable for plant uptake, the capacity of the isolated actinomycetes to secrete phosphatase activity was determined under laboratory conditions. A huge variation in the capacities to produce acid and alkaline phosphatases among the different isolates was observed. These enzyme activities and the capacities to hydrolyze phytate in the fermentation broth were significantly dependent on medium composition. In general, substitution of arginine and glycerol in the modified glycerol arginine medium (MGA) with other nitrogen and carbon sources resulted in a significant reduction of phytate dephosphorylation.

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“…(Rodríguez and Fraga, 1999), Mesorhizobium sp. (Peix et al, 2001), Penicillium sp. and arbuscular mycorrhizal fungi (Ouahmane et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Distribution of actinomycetes in different soil ecosystems and effect of media composition on extracellular phosphatase activity

Ghorbani-Nasrabadi

Greiner

Khonakdar

et al. 2013

J. Soil Sci. Plant Nutr.

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“…But studies on phosphate solubilizing ability of Rhizobium strains are very limited [4][5][6][7][8]. The main advantage of using rhizobia as a phosphate-solubilizing microorganism will be their benefi cial nutritional effect resulting both from phosphate mobilization and nitrogen fi xation [9]. In the present study, 46 rhizobia, isolated from root and stem nodules of 20 different legume hosts, were tested for their ability to solubilize tricalcium phosphate (TCP).…”

Section: Introductionmentioning

confidence: 99%

Phosphate solubilization by Rhizobium strains

Sridevi

Mallaiah

2009

Indian J Microbiol

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Forty-six Rhizobium isolates from legume root and stem nodules were examined for their phosphate-solubilizing ability on Pikovskaya's agar medium. Rhizobium isolates from root nodules of Cassia absus, Vigna trilobata and three strains from Sesbania sesban showed zone of tricalcium phosphate (TCP) solubilization. The isolate from C. absus showed maximum solubilization (620 μg/ml) after 12 d of incubation, while the Rhizobium sp. strain 26 (from S. sesban) showed the least amount (150 μg/ml) of phosphate solubilization. Among the carbon sources tested for their ability to solubilize TCP, maximum solubilization (620 μg/ml) was observed in glucose by Rhizobium isolate from C. absus. Phosphate solubilization increased with increase in glucose concentration steeply up to 2% and slowly above this concentration in four isolates. Among the nitrogen sources tested, maximum solubilization (620 μg/ml) was observed in ammonium sulphate by Rhizobium isolate from C. absus.

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“…Cells are motile with a polar flagellum (see Supplementary Fig. I, available in IJSEM Online) and grew as weakly translucent, yellow-coloured colonies on nutrient agar.For 16S rDNA sequencing, DNA extraction was carried out as described previously (Rivas et al, 2001). Amplification and sequencing of 16S rDNA were performed as described previously (Rivas et al, 2003a).…”

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confidence: 99%

“…P. graminis DSM 11363 T was included in these studies and analysed under the same conditions. Ability to solubilize phosphate was tested in YED-P medium as described previously (Peix et al, 2001). Mesorhizobium mediterraneum UPM-Ca36 T and Sinorhizobium meliloti ATCC 9930 T were used as positive and negative controls, respectively.…”

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Pseudomonas rhizosphaerae sp. nov., a novel species that actively solubilizes phosphate in vitro

Peix

Rivas

Mateos

et al. 2003

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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A bacterial strain (designated IH5 T ), isolated from rhizospheric soil of grasses growing spontaneously in Spanish soil, actively solubilized phosphates in vitro when bicalcium phosphate was used as a phosphorus source. This strain was Gram-negative, strictly aerobic, rod-shaped and motile. The strain produced catalase, but not oxidase. Cellulose, casein, starch, gelatin, aesculin and urea were not hydrolysed. Growth was observed with many carbohydrates as the carbon source. The main non-polar fatty acids detected were hexadecenoic acid (C 16 : 1 ), hexadecanoic acid (C 16 : 0 ) and octadecenoic acid (C 18 : 1 ). The hydroxy fatty acids detected were 3-hydroxydecanoic acid (C 10 : 0 3-OH), 3-hydroxydodecanoic acid (C 12 : 0 3-OH) and 2-hydroxydodecanoic acid (C 12 : 0 2-OH). Phylogenetic analysis of 16S rRNA indicated that this bacterium belongs to the genus Pseudomonas in the c-subclass of the Proteobacteria and that the closest related species is Pseudomonas graminis. The DNA G+C content was 61 mol%. DNA-DNA hybridization showed 23 % relatedness between strain IH5 T and P. graminis DSM 11363 T . Therefore, strain IH5 T belongs to a novel species from the genus Pseudomonas, for which the name Pseudomonas rhizosphaerae sp. nov. is proposed (type strain, IH5 T =LMG 21640 T =CECT 5726 T ).Phosphorus is an essential plant nutrient that is added to soil as soluble inorganic phosphates, a large proportion of which becomes insoluble and therefore unavailable to plants (Singh & Kapoor, 1994). Many species of bacteria are able to solubilize phosphates in vitro and most of them live in the plant rhizosphere. At present, bacilli, rhizobia and pseudomonads are the most studied phosphate-solubilizers (Rodríguez & Fraga, 1999). Nevertheless, only a small number of species that presently belong to the genus Pseudomonas sensu stricto are known to be phosphatesolubilizers and they all belong to rRNA group I (Palleroni et al., 1973;Palleroni, 1992). Pseudomonas putida (Viveganandan & Jauhri, 2000;Kumar & Singh, 2001;Manna et al., 2001; Villegas & Fortin, 2002), Pseudomonas aeruginosa (Musarrat et al., 2000), Pseudomonas corrugata (Pandey & Palni, 1998), Pseudomonas stutzeri (Vázquez et al., 2000) and Pseudomonas fluorescens (Di Simine et al., 1998;Deubel et al., 2000) are the most studied species. Nevertheless, many rhizospheric, phosphate-solubilizing bacterial species remain unknown and more studies are needed to reveal the high biodiversity of these bacteria. Although the study of rhizospheric bacteria is difficult, due to the high number of bacteria present in soil, characterization and identification of these bacteria are necessary for wide ecological studies of the plant rhizosphere.During a wide study of phosphate-solubilizing, rhizospheric bacteria in soils from northern Spain, we isolated a strain that produced a yellow pigment in media that contained glucose as the carbon source and formed a transparent 'halo' around its colonies in media that contained insoluble bicalcium phosphate as the phosphorus source.A sample...

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Growth promotion of chickpea and barley by a phosphate solubilizing strain of Mesorhizobium mediterraneum under growth chamber conditions

Cited by 250 publications

References 27 publications

Distribution of actinomycetes in different soil ecosystems and effect of media composition on extracellular phosphatase activity

Distribution of actinomycetes in different soil ecosystems and effect of media composition on extracellular phosphatase activity

Phosphate solubilization by Rhizobium strains

Pseudomonas rhizosphaerae sp. nov., a novel species that actively solubilizes phosphate in vitro

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