Isolation and identification of new beneficial bacterial strains from rhizosphere of Citrus sinensis orchards

Document Type : Original Research Papers


1 Department of Biology, Science and Research branch, Islamic Azad University, Kerman, Iran

2 Department of Biotechnology, Institute of Science and High technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran

3 Department of Biology, Faculty of Sciences, Shahid Bahonar University, Kerman, Iran

4 Department of Biochemistry, faculty of biological sciences,Tarbiat Modares University, Tehran, Iran


The rhizosphere is the area around the root of a plant occupied by a unique population of useful
bacteria known as plant growth promoting rhizobacteria (PGPR). In this study, the isolation and
identification of rhizobacteria from orange (Citrus sinensis) orchards using 16S rRNA gene, as well as
biological and biochemical assays is reported. Analysis of 16S rRNA gene was confirmed by
biological and biochemical assays and showed that the isolated bacteria belong to the genera Bacilli,
Enterobacter and Pseudomonas. Accordingly, Enterobacterkobei MR-R2, Pseudomonas putida MRR5,
Bacillus cereus MR-R, Bacillus thuringiensis MR-R1 and Bacillus mycoides MR-R4 were
identified and registered in GenBank. The results of phosphate solubilization testing revealed that the
maximum rate of phosphate solubilization was observed for B. thuringiensis, and E. kobei; however,
B. cereus, B. mycoides, and P. putida indicated the least activity. It can be concluded that the isolated
strains (especially B. thuringiensis) are newly identified phosphate solubilizing bacterial strains,
among which B. thuringiensis can be used for growth promotion of orange trees.


Main Subjects

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