Abstract:
Two phosphate solubilizing Pantoea strains (P. agglomerans and P. rodasii) were employed in elucidating
their phosphate solubilizing potential under different carbon and nitrogen sources, pH, temperature and salt
conditions. Plant growth promoting characteristics such as ACC deaminase activity, indole acetic acid (IAA),
HCN, ammonia, and siderophore production of the two strains were assessed in vitro. Potential applicability
of the strains as bio-inoculants was also evaluated in pot experiments conducted under green house conditions.
Phosphate solubilization measured as the amount of phosphorous released into the medium was recorded as
810 and 788 µg ml-1 respectively by P. agglomerans and P. rodasii. Glucose at the rate of 2% was found be the
best carbon source, while (NH4)2SO4 was the best nitrogen source for both strains. Despite a slight decrease in
phosphate solubilization observed at higher temperature, pH and salt concentrations, both strains could
withstand against a range of temperature (30-35o
C), pH (7-9) and the presence of NaCl (up to 5%) without
much compromising the phosphate solubilization. Different plant growth promoting traits (ACC deaminase
activity, IAA, HCN, ammonia, and siderophore production) of the strains and their ability to promote the
growth of green gram seedlings indicate that both strains possess high potential to be used as bio-inoculants
