The effect of a seed coating with Origanum vulgare essential oil on Clavibacter michiganensis subsp. michiganensis

Abstract

The study aimed to evaluate the efficacy of a seed film coating with Origanum vulgare Linnaeus essentialoil (EO) against Clavibacter michiganensis subsp. michiganensis (Cmm) on tomatoes. Tomato seeds (cv. Rio Grande)coated with different doses of EO derived from O. vulgare were inoculated with Cmm (1.8 × 108 CFU/mL). O. vulgare'sEO showed a remarkable inhibition effect on the Cmm growth. The EO effect against Cmm was determined basedon the parameters, such as the inhibition zone and bacterial population in a seed. The GC-MS analysis of EO showedthat carvacrol is the major component (at 74.05%), which may inhibit the bacterial growth. Later, we have expandedour studies to determine the inhibitory effect of the EO's mode of action on the pathogenic bacteria with a moleculardocking analysis based on the molecular protein-ligand interaction. The results showed that carvacrol has a stronginteraction with the bacterial expansin protein (PDB 4JJO) of Cmm and the qPCR analyses confirmed the effect of theO. vulgare treatment against Cmm. This original approach has the prominent potential to prevent seed transmissionof Cmm for seed quality in the world, suggesting a method for paving the way for Cmm disease management.