Evaluation of seed biopriming on tomato leaf spot biocontrol and plant growth factors

Tomato bacterial leaf spot caused by Pseudomonas syringae pv. syringae is a serious problem for tomato production in the greenhouse and field. In this study, effect of some probiotic rhizobacteria evaluated on seed indexes, plant growth factors and biocontrol of syringae leaf spot in the laboratory and greenhouse. All probiotic and pathogenic bacteria isolated from tomato fields in West Azarbaijan. Identification of benefit rhizobacteria carried out via phenotypic and molecular methods. Ability of 21 selected rhizobacteria of Bacillus subtilis and Pseudomonas fluorescens strains in secondary metabolites production was investigated via two methods. In first method, filtered suspension spotted on medium, and in second one bacterial cell was poured in wells created on medium. In addition, the strains were studied for lipase, protease and alkaline protease production. In both methods, studied strains reduced the pathogenic bacterial growth in the laboratory, and hydrolytic enzymes produced by all strains. Some of the studied strains increased percentage and speed of tomato seed germination. Selected strains increased the growth factors of tomato plants in greenhouse. The greatest effect was observed in Pf23 and Bs11 strains. The probiotic bacteria reduced the disease between 25 and 81.25% compared to the control. In the greenhouse, Bs11 with 81.25% and Bs6 and Pf23 with 61.50% disease decreasing compared to control, showed the most effect in reducing leaf spots. Bs11 and Pf23 were selected as the best strains in effect on tomato growth factors and biocontrol of syringae leaf spot.