Preliminary Characterization of the First Phosphate Solubilizing Bacteria Isolated From the Rhizospheric Soil of the Jujube Plant Ziziphus

Abstract

The use of rhizobacteria that solubilize inorganic phosphates as biofertilizers is considered as a suitable solution for sustainable agriculture. Only limited number of studies have been carried out on the jujube plant Ziziphus, which is frequently encountered the Mediterranean basin, particularly in North Africa. Here, we conducted the first study on jujube to characterize the native phosphate solubilizing bacteria (PSB) from its rhizospheric soil. jujube was selected because of its ability to survive within arid climates by tolerating biotic and abiotic stresses. A total of 41 rhizobacteria isolated from rhizospheric jujube collected from the experimental farm of Benguerir (Morocco) were able to solubilize tri-calcium phosphate (TCP) on NBRIP agar. Next, thirteen of the best performing isolates were subsequently tested for phosphate solubilization in liquid media and for antibiotics resistance. Eleven exhibit a great ability to release soluble phosphate from TCP with ranged concentrations between minima at 160 mg/L and maxima at 260 mg/L. Moreover, several PSB strains confer resistance at least to one of the tested antibiotics. Analysis of 16S rDNA sequencing demonstrated that PSB isolates were closely related to the genus Pseudomonas, Bacillus, Enterobacter, or Paenibacillus.