Antimicrobial properties of Lactobacillus bacteria from rhizosphere of Helianthemum ledifolium and desert truffle Terfezia claveryi soil in Golestan province

The widespread use of chemicals and pesticides has always led to risks to the human health, animals, ecological changes and imbalances in environmental sustainability. During this study, sampling was followed by collecting samples of rhizosphere of Helianthemum ledifolium and desert truffle surrounding soils in Golestan province, selected 7 strains of gram-positive Lactobacillus and catalase-negative which was isolated and identified on PDA, NA and MRS medium. Biochemical tests showed some of the bacterial strains were able to grow in acidic condition from pH 3 to 8 and they were able to tolerate up to 8% salt. Strains were also able to grow at minimum 15 °C and maximum 45 °C and the fermentation of the sugars were tested by the carbohydrate fermentation test. Using the 16S rDNA gene sequence, different strains of R11, R12, R21, R22, R31, S11 and S12 were identified as L. plantarum. In agar well-diffusion test, the highest inhibitory level was significantly observed in Pseudomonas syringae and Staphylococcus aureus with a diameter of 11 mm by R31 and S11 isolated from H. ledifolium root and desert truffle soil, respectively. In antifungal activity, the maximum growth inhibitory for P. expansum and F. solani were 69.37 and 66.69 percent, respectively. Sporulation reduced in P. expansum in comparison to the control. The results based on SAS system and completely randomized design showed that lactic acid bacteria with plant and soil origin could inhibit the growth of pathogenic fungi and bacteria with high spectrum and can be used as safe biocontrol bacteria in post- harvest crop contamination.