Ozone treatment inactivates common bacteria and fungi associated with selected crop seeds and ornamental bulbs

The use of disease-free seeds or bulbs is very crucial to ensure sustainable and profitable agricultural production. Seed-borne pathogens which are responsible for significant yield losses in various crops need to be successfully eliminated with appropriate seed treatments. In this study, we investigated the efficacy of gaseous ozone (O(3)) and ozonated water treatments on the inactivation of seed-borne fungal and bacterial pathogens of widely cultivated vegetable and cereal seeds, and ornamental bulbs. We demonstrated that O(3) application to tomato and cucumber seeds inactivates Fusarium oxysporum f. sp. lycopersici, Fusarium oxysporum f. sp. radicis-lycopersici, Clavibacter michiganensis subsp. michiganensis, Pseuodomonas syringae pv. tomato, and Pseudomonas syringae pv. lachrymans, respectively, with no negative effect on seed germination rate. The sterilization capacity of O(3) has substantially increased when the seeds were soaked in water before the treatments. The saprophytic fungal load and the infection rate of Pectobacterium carotovorum subsp. carotovorum on several species and cultivars of ornamental bulbs were suppressed by O(3) treatment. A strong decrease in the infection rate of Tilletia caries was also shown in O(3)-treated wheat seeds under field conditions. Overall, the current study indicated that O(3) treatment has great potential in ensuring the use of disease-free seeds or other propagation materials, which is indispensable at the beginning of crop production.