Pseudomonas rhizosphaearicae a new species of genus Pseudomonas that actively solubilizes phosphate in vitro

Alvaro Peix¹, Raúl Rivas², Pedro F. Mateos², Eutoquio Martínez-Molina², Claudino Rodríguez-Barrueco¹ and Encarna Velázquez²

^1.Departamento de Producción Vegetal. IRNA. CSIC. Salamanca, SPAIN

²Departamento de Microbiología y Genética, Facultad de Farmacia, Edificio Departamental, Universidad de Salamanca, Salamanca 37007, SPAIN.

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We isolated a strain, IH5, that actively solubilizes phosphate in vitro from the rhizospheric soil of plants spontaneously growing in a soil of Spain. This strain showed a great ability to solubilize phosphates in vitro and were able to retain it after five culture passes. The sequencing of 16S rRNA of strain SAIH5 shows that the closest related species is Pseudomonas graminis with a similarity of 98,6%. These data indicate that these strains belong to a new species of genus Pseudomonas for which we proposed the name of Pseudomonas rhizosphaericae sp. nov. The strain IH5 is a strictly aerobic Gram negative rod. Catalase and oxidase were positive. The strain showed nitrate and nitrite reduction. Urease, b-galactosidase, caseinase, amylases, arginine dehidrolase, gelatinase and esculin hydrolisis were not produced. Glucose, arabinose, mannose, gentiobiose, caprate, malate and citrate were used as only carbon source. N-acetyl-glucosamine, maltose and adipate were not used as carbon source. The strain was not able to grow in presence of 7% NaCl.