Low phosphate solubility is one of the most important factors limiting the plant growth in Indian soils. Many microorganisms can enhance phosphate solubility, but little is known about the magnitude of their phosphorussolubilizing ability. | P. TALLAPRAGADA, U. SESHACHALA Turk J Biol 36 (2012) 25-35 © TÜBİTAK doi: Phosphate-solubilizing microbes and their occurrence in the rhizospheres of Piper betel in Karnataka, India Padmavathi TALLAPRAGADA, Usha SESHACHALA Center for PG Studies, Jain University, Jayanagar, Bangalore 560011, Karnataka - INDIA Received: Abstract: Low phosphate solubility is one of the most important factors limiting the plant growth in Indian soils. Many microorganisms can enhance phosphate solubility, but little is known about the magnitude of their phosphorussolubilizing ability. The native populations of phosphate-solubilizing bacteria and fungi were studied in different rhizospheric soil samples obtained from betel vine plants (Piper betel L.) in order to compare the results. The present study focuses on the phosphate-solubilizing capacity of bacteria and fungi in rhizospheric soil samples obtained from betel vine plants, revealing the dominance of Aspergillus species ( mm) as major phosphate solubilizers, along with Bacillus subtilis ( mm) among the bacteria that utilize tricalcium phosphate, potassium dihydrogen phosphate, and rock phosphate as phosphate sources. The other phosphorus-solubilizing microorganisms were Bacillus species, Streptomyces, Aspergillus fumigatus, Nocardia, actinomycetes, and certain yeasts. The presence of high numbers of phosphate-solubilizing bacterium Bacillus subtilis (3 × 106 cfu g–1) and fungus Aspergillus niger (3 × 105 cfu g–1) in the rhizospheric zones of Piper betel plants explains how the plants obtain their nutrient requirements. The identity of Aspergillus species and Bacillus with the maximum zone was confirmed using molecular sequencing with 16s rDNA. The sequence data were aligned and analyzed to identify the bacteria along with their closest neighbors. Key words: Aspergillus, Bacillus, phosphates, Piper betel, rhizosphere Introduction The betel vine plant (Piper betel L.) is a climber with .
