IMPROVED DELIVERY OF BIOCONTROL PSEUDOMONAS AND THEIR ANTIFUNGAL METABOLITES USING ALGINATE POLYMERS

Alginate polymer was evaluated as a carrier for seed inoculation with a genetically modified strain Pseudomonas fluorescens F113LacZY, which protects sugar-beet against Pythium-mediated damping-off. F113LacZY s urvived in alginate beads at 5 log(10) CFU/bead or higher counts for 8 weeks of storage, regardless of the conditions of incubation. In plan t inoculation experiments, colonisation of the growing area of the roo t by F113LacZY, derived from alginate beads placed in the soil next to the seed or from an alginate coating around the seeds, was improved c ompared with application of just free cells of the strain. F113LacZY t rapped in alginate beads was an effective producer of antifungal phlor oglucinols as indicated by direct HPLC quantification of phloroglucino ls and in vitro inhibition of both the indicator bacterium Bacillus Su btilis A1 and the pathogenic fungus Pythium ultimum. Alginate polymer represents a promising carrier for the delivery of biocontrol inoculan ts for root colonisation and production of antifungal metabolites.