Combined inoculation of phosphate solubilizing bacteria with mycorrhizae to alleviate the phosphate deficiency in Banana

Phosphate solubilizing bacteria (PSB) and arbuscular mycorrhiza fungi (AMF) are plant beneficial soil microorganisms that emerged as an attractive approach to replace chemical-based fertilizers. However, the role of these microbes in the combined inoculation with tricalcium phosphate (TCP) is poorly known as biofertilizers in Banana plants. The present study aim to identify PSB from the rhizospheric zone of Banana plants and investigate their growth stimulatory effect on the Banana plant after combining with AMF to alleviate the phosphate deficiency. Based on P solubilization, out of seven PSBs, one potent PSB was molecularly identified as Staphylococcus sp. strain PSB03, and also this is the first report among the reported PSB. Isolated strain PSB03 solubilized rock phosphate (RP) (tricalcium phosphate (TCP) and sodium phytate (SP)) produced indole acetic acid, ammonia, hydrogen cyanide, cell lytic enzymes and utilizes 11 different types of carbon sources. From the field (pot) study, treatment 4 (T4) (combination of PSB03 and AMF) showed the most significant effect on Banana plants. The result shows a 4 and 3-folds increment in morphological and biochemical parameters compared to uninoculated control (T1). Also, T4 shows a 5-folds high phosphate content compared to control (T1). The results demonstrated that the strain PSB03 shows rapid and high solubilization of rock phosphate (TCP and SP), had various PGP traits and was equally compatible with AMF (T4) to promote plants growth at the field level (pot-experiment). Hence, we concluded that the identified bio inoculants (T4) could be considered as a biofertilizers for sustainable Banana cultivation.