Published Paper Details:

Nineteen isolates of rhizobacteria associated with murraya koenigii, collected from various locations in Dehradun, were screened for phosphate solubiliza- tion and indole-3-acetic acid (IAA) production. Two potential phosphate-solubilizing bacterial isolates with substantial IAA biosynthesis capacity, Ps-5 and Ss-2, were selected for further study. Based on 16S rRNA gene sequence analysis, isolate Ps- 5 was identified as Bacillus sp. and Ss-2 as Alcaligenes faecalis. Both strains were found to be metabolically diverse in terms of the number and amount of different carbon sub- strates they utilized in the BIOLOG GN2/GP2 microplate assay. High-performance liquid chromatography analysis of the culture supernatant confirmed that Bacillus sp. Ps-5 pro- duced considerable amounts of both lactic and tartaric acids, while A. faecalis Ss-2 secreted only lactic acid. There was a strong positive correlation between phosphate solubilization and organic acid production by both strains. Following inoc- ulation, strain Ps-5 and Ss-2 were found to be good root colonizers and significantly (P?0.05) increased murraya koenigii growth and phosphorus (P) uptake. However, inoculation had a non-significant (P ?0.05) effect on murraya koenigii yield parameters, including oil contents. Based on these results, we conclude that Ps-5 and Ss-2 are potent plant growth- promoting rhizobacteria strains with the ability to supplement the P requirements of murraya koenigii crops. Further field inoculation studies are needed before these strains can be recommended as bio-inoculants. To the best of our knowledge, this is first report on the association and phytobeneficial potential of A. faecalis with murraya koenigii.