معرفی باکتری پروبیوتیک گیاهیBacillus velezensis از اندوریزوسفر گیاه گوجه فرنگی

Bacillus velezensis belongs to Terrabacteria, Bacillales, Bacillaceae family and Bacillus amyloliquefaciens group. This bacterium was obtained from tomato endorhizosphere in Kermanshah province. In order to molecular identification of this isolate, total DNA extracts with Kiagen kit and whole genome sequence of this strain was performed using Illuminia Hiseq technology in Cornell University. The DNA sequence, was quality controlled by FastQC software.Then genomic locations and CDs (Coding Sequences) was identified in RASTdatabase. Finally the sequencing data was compared with existing sequences in NCBI and SEED databases. Results showed that, this isolate has high similarity to (%100) B.velezensis. The genome of this isolate contains 4132868bp and 4329 Coding Sequenses (CDs), 58 tRNAs and 7 rRNAs. Plant growth-promoting factors including root ,shoot length and dry weight and seed germination was evaluated after inoculation with 1×10-9 CFU/ml bacterial suspention in vitro and greenhouse. In both conditions, B. velezensis promoted of tomato growth indices including, germination rate, seedling growth rate, seed vigor index, hypocotyle and epicotyle length, root and shoot length and their dry weight. In addition, some biocontrol and plant growth promoting determinant of B.velezensis were assayed, such as: phosphate solubilization, siderophore production, hydrogen cyanide emission and auxin production. Results showed that this isolate can dissolve inorganic phosphate and it has the maximum ability to produce hydrogen cyanide. Also, siderophore production determined with orange halo around the bacterium colony. Auxin production was estimated at 4 mg / L. The antifungal activity against Fusarium oxysporum fsp. lycopersici was showed that, this strain can inhibit the mycelial growth in dual culture and volatile compounds methods about 83% and 58% respectively. Furthermore,the Pot experiment results show that it had a significant effect to reduced disease symptoms on tomato plants. All the tests were carried out in randomized complete design with three replicates. In conclusion, disease suppression and PGPR tests suggest that B.velezensis has a good potential to be introduced as a plant probiotic bacteriain tomato fields . This is the first report of B.velezensis bacteria in Iran