Abstract
Hyperhydricity, or vitrification, is a physiological malformation affecting tissue culture-generated plants. This malformation is associated with excessive hydration and poor lignification and results in poor regeneration of plants. We have tested hyperhydricity prevention in oregano by several nonspecific polysaccharide-producing rhizosphere bacteria. Among these bacteria, Pseudomonas mucidolens and another Pseudomonas sp. prevented hyperhydricity and improved acclimation of oregano clones. These two bacteria have more advantages for commercial applications than Pseudomonas strains isolated previously from oregano.