INTERACTION OF HYPERHYDRICITY-PREVENTING PSEUDOMONAS SP WITH OREGANO (ORIGANUM VULGARE) AND SELECTION OF HIGH PHENOLICS AND ROSMARINIC ACID-PRODUCING CLONAL LINES

Phenolic metabolites from oregano and related species in the family La miaceae are important sources of antimicrobials and antioxidants. The content of phenolic metabolites in oregano and related species are hig hly variable due to genetic heterogeneity. This genetic heterogeneity is due to the breeding character being influenced by natural cross-pol lination. In order to develop gene pools to improve ingredient quality and quantity genetically uniform shoot-based clonal lines were isolat ed using plant tissue culture techniques. Clonal lines were generated from multiple shoots induced by 1 mg/l benzylaminopurine in standard M urashige and Skoog medium with 3% sucrose. Under these optimum conditi ons 7 - 10 shoots per explant were generated for further clonal propag ation or regeneration of plants. Shoot-inducing hormones like thidiazu ron and adenine sulfate did not improve multiple shoot-forming ability . Individual shoots of several individual clonal lines with each origi nating from a single heterozygous seed were then inoculated with a nov el Pseudomonas sp. Following 30 days of growth on hormone-free Murashi ge and Skoog medium, morphology, tolerance to Pseudomonas, phenolics a nd rosmarinic acid content were measured and compared to uninoculated controls in 7 clonal lines of oregano. Results indicate that Pseudomon as sp.mediated stimulation of phenolics and rosmarinic acid in various oregano clonal lines were directly correlated to tolerance to Pseudom onas sp.. Among these clonal lines, OM-1 had the highest increase in p henolics and rosmarinic acid with corresponding enhanced tolerance to Pseudomonas sp.. This provides an unique strategy to isolate high phen olics-producing, genetically uniform clonal lines using Pseudomonas sp .. From a basic research perspective such clonal lines are essential f or characterization of biochemical pathways of specific phenolic metab olites. From an applied research perspective, selection of elite clona l lines serve to provide extracts with uniform phenolic ingredients fo r use as antioxidants and antimicrobials in food systems.