Biochemical changes induced in regenerants of Fragaria X Ananassa Duch. by the in vitro treatment with fungal elicitors

The aim of the present study was to describe the biochemical changes induced in regenerants of Fragaria X Ananassa Duch. by the in vitro treatment with fungal elicitors isolated from Trichoderma viride, Penicillium chrysogenum and Botrytis cinerea strains. We combined anatoxinic serum from these three microorganisms to activate different defense signaling pathways in our in vitro system. Strawberry regenerants responded in a complex way to treatments with fungal elicitors with gradual forms of stress, up to foliar necrosis. The enzymes involved in the metabolism of reactive oxygen species (ROS) expressed different activities in the treated variants compared to the control, 24 hrs after the last treatment: superoxid dismutase (SOD) activity increased while catalase (CAT) and peroxidase (PDX) activity decreased suggesting a significant ROS accumulation, with complex and opposite effects on plant cells, including the activation of hypersensitive cell death. The tested mixture of anatoxinic sera from the three microorganisms acted as a strong external stimulus in our in vitro system.