Solubilization of Inorganic Phosphates and Plant Growth Promotion by Pantoea Strains

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 (NH 4 ) 2 SO 4 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 (30-35 o 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.

Co-culture development and bioformulation efficacy of psychrotrophic PGPRs to promote growth and development of Pea (<i>Pisum sativum</i>) plant

“…These IAA production data suggest that the isolated strains act as effective bioinoculants. These trends agree with previous reports indicating IAA formation in the stationary stage of culture (Park et al, 2017;Sahasrabudhe, 2011;Verma et al, 2016;Walpola et al, 2013). The confirmation of IAA with the TLC findings are in agreement with previous reports (Sahasrabudhe, 2011).…”