The Molecular Characterization of Rhizobacteria Isolates from Saki, Nigeria

Plant growth promoting Rhizobacteria (PGPR) are important in the agricultural sector. Although different microorganism live in the soil but thrive in PGPR rhizosphere zones, improve the production and protection to them from diseases by production of metabolites, volatile compounds and phytohormones and Induced Systemic Resistance (ISR). This study was aimed at isolating and characterize molecularly the bacteria from the rhizosphere of pepper (Capsicum annuum), vegetable (Spinacia oleracea), rice (Oryza sativa) grown in Saki. The rhizosphere sample of pepper, rice and vegetable were collected between the hours of 1:40-2:00pm. The colonial characteristics, Gram staining techniques, biochemical test were carried out. The isolates were tested against eight antibiotics (Ceftriaxone, Gentamicin, Ceftazidime, Ofloxacin, Augmentin, Cefuroxime, Erythromycin, and Cloxacillin) by using disc diffusion method. PCR techniques and subsequent use of sanger method was used for sequencing. DNA extract was obtained using the lysozyme-SDS-phenol chloroform method in the prepared kits by Jena Bioscience. Amplification of the 16S rRNA gene was performed with the use of T1-Thermocycler PCR machine with 1492R primers pA (5′-TAC GGYBTAC CTT GTT ACG ACT T3′) and 27F primers pH (5′-AGAGTTTGATCMTGGCTCAG3'). This Primer was used for PCR amplification of 16S rRNA gene. All bacterial isolates were catalase (+) and indole (-). Antibiotics screening showed that all isolates resist most of the antibiotics except Ofloxacin and ciprofloxacin while sample 1, 2, 5 and 6was susceptible to Gentamicin. Six bacterial isolates obtained were characterized on molecular basis of 16S rRNA sequencing. The identified isolates were: Bacillus thuringensis B. weidmanii, B. cereus.