Enhanced Biocontrol Activity of Rhodotorula mucilaginosa Cultured in Media Containing Chitosan against Postharvest Diseases in Strawberries: Possible Mechanisms Underlying the Effect

The effect of Rhodotorula mucilaginosa cultured in media containing chitosan on its antogonistic activity against postharvest diseases of strawberries and the possible mechanisms involved are discussed. Two-dimensional gel electrophoresis were applied in the analysis of the proteins of R. mucilaginosa in response to chitosan. Compared with the application of R. mucilaginosa alone, the biocontrol efficacy of the yeast combined with 0.5% chitosan was enhanced greatly, with significant increase in chitinase activity of antagonistic yeast, polyphenoloxidase, peroxidase, phenylalanine ammonia lyase, chitinase and beta-1,3-glucanase activity, and with an inhibition of lipid peroxidation of strawberries. The population of R. mucilaginosa harvested from NYDB amended with chitosan at 0.5% increased rapidly in strawberry wounds compared with those harvested from NYDB without chitosan. In the cellular proteome, several differentially expressed proteins were identified, most of which were related to basic metabolism.