Phosphate solubilizing bacteria: Assessment of their effect on growth promotion and phosphorous uptake of green gram (Vigna radiata [L.] R. Wilczek)

Buddhi Charana Walpola1, and Min-Ho Yoon1*
The aim of this work was to isolate phosphate solubilizing bacteria (PSB) and assess their effect on the growth of mung bean (Vigna radiata [L.] R. Wilczek) plants. Of 31 isolated PSB strains, two efficient strains, identified as Pantoea agglomerans (PSB-1) and Burkholderia anthina (PSB-2), were employed in further studies. Maximum P solubilization (720.75 µg mL-1) was recorded from the cultures co-inoculated with P. agglomerans and B. anthina. A strong positive correlation was found between pH and soluble P concentration in the medium, as well as between titratable acidity and P solubilization. Both strains under greenhouse conditions remarkably enhanced shoot and root length, shoot and root dry matter, and P uptake of mung bean plants. Growth was found to be further improved by adding tricalcium phosphate (TCP) with PSB inoculation. Co-inoculation of both PSB strains and adding TCP exhibited the highest growth performances and P uptake of mung bean plants; this implies that their applicability as a promising alternative to minimize the P problem in agricultural soils.
Keywords: Burkholderia anthina, co-inoculation, Pantoea agglomerans, phosphate solubilization, tricalcium phosphate, Vigna radiata.
1Chungnam National University, College of Agriculture and Life Sciences, Daejeon, 305-764, Korea. *Corresponding author (mhyoon@cnu.ac.kr).