Phosphate solubilization by Rhizobium strains

Abstract

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.

Phosphate Solubilization Activity of Rhizobial Strains Isolated From Root Nodule of Cluster Bean Plant Native to Indian Soils

“…This type of negative correlation between phosphate solubilization and pH by rhizobial strains was reported earlier also (Sridevi and Mallaiah, 2009). …”

“…This decrease in pH is a basic principle in phosphate solubilization and may be related to the production of organic acids (Sridevi and Mallaiah, 2009) and the release of protons (Chen et al, 2006). This type of negative correlation between phosphate solubilization and pH by rhizobial strains was reported earlier also (Sridevi and Mallaiah, 2009).…”

Phosphate solubilization by endophytic bacteria isolated from banana trees

“…Among the bacteria able to solubilize phosphate, the genera Rhizobium (Sridevi and Mallaiah 2009), Agrobacterium, Pseudomonas, Burkholderia, Erwinia (Verma et al 2001, Garg et al 2001, Paenibacillus (Wang et al 2012), Bacillus (Silva Filho and Vidor 2000) and Lysinibacillus sp. (Andrade et al 2014) are of interest.…”

Characteristics and biodiversity of endophytic phosphorus- and potassium-solubilizing bacteria in Moso Bamboo (Phyllostachys edulis)

“…Phosphate fertilizers can easily form an insoluble state in soil [17,26], while the majority of soil potassium also exists in the form of silicate minerals which cannot be absorbed by the plant. Therefore, full absorption of soil-based phosphorus and potassium by plants has important practical significance in promoting crop yield and quality, reducing the environmental impact of fertilizer, and improving the physical and chemical properties of soil.…”