Solubilization of phosphate by a strain of Rhizobium leguminosarum bv. trifolii isolated from Phaseolus vulgaris in El Chaco Arido soil (Argentina)

Abstract

Several strains were isolated from Phaseolus vulgaris plants growing in a soil from El Chaco Arido (Argentina). Although most of strains nodulating Phaseolus are not P-solubilizers in plates containing bicalcium phosphate, we tested the isolates and among them, one strain (ARPV02) was able to solubilize phosphate in plates. This strain showed a high ability to nodulate and to fix nitrogen in common bean. Sequencing of 16S rRNA was performed in the strain ARPV02, showing a 100% similarity with the former type strain of Rhizobium trifolii ATCC14480. This strain is currently considered as a biovar of species Rhizobium leguminosarum together biovars viceae and phaseoli. These biovars have been defined basing on their ability to nodulate a concrete group of legumes. In this way, the strains belonging to biovar trifolii nodulate Trifolium. However, in previous studies we have shown that in Spanish soils strains from this biovar nodulate Phaseolus. Besides the solubilization of phosphate, the strain ARPV02 isolated in this study is able to movilize phosphorous to common bean plants.