Phosphate-solubilizing Bacillus sp. enhances growth, phosphorus uptake and oil yield of Mentha arvensis L.

In the present study, phosphate solubilizing rhizobacterial isolate STJP from the rhizosphere of Stevia rebaudiana was identified as a Bacillus sp. on the basis of phenotypic, biochemical, and 16S rRNA gene sequencing. In addition to phosphate solubilization ability, isolate Bacillus sp. STJP produced a significant quantity of siderophore (16.06 µg/ml) and indole 3-acetic acid (30.59 µg/ml). In the greenhouse experiment, treatment with STJP along with tricalcium phosphate (TCP200) showed significant increase in the plant growth parameters, oil yield and P uptake in M. arvensis as compared to the control plants. Amongst all the treatments, highest oil yield and menthol content were observed when treated with Bacillus sp. STJP + TCP200. Hence, an integrated approach of using Bacillus sp. STJP along with TCP can be used to increase the production of menthol and oil yield of M. arvensis. This approach of using fertilizer along with phosphate solubilizing Bacillus sp. worked very well and was more effective in comparison with individual treatment of fertilizer or plant growth promoting rhizobacteria. A combined use of efficient phosphate solubilising bacteria loaded with plant growth promoting characters along with TCP can thus be far effective way for enhancing the yield of crops in a sustainable manner.