Wageningen UR Greenhouse Horticulture, Plant Research International and NSure have joint forces to screen the expression of genes, metabolites and pathogen-related enzymes in relation to systemic defence mechanisms against Botrytis in cut flowers. Tomato was used as a model, while gerbera was chosen as a reference cut flower.
Plants were either pre-treated with specific chemicals known to be induced in plant pathogen interactions, i.e. jasmonic acid and 2,6–dichloroisonicotinic acid (INA, a glucanase/chitinase-inducer) or non-treated (controls) before being infected with Botrytis. Botrytis outgrowth and damage on leaves and flowers were scored visually. At the same time leaf samples were taken for large-scale screening using both transcriptomics (gene profiling) and metabolomics (metabolite profiling), as well as the activity of specific defense-related enzymes was studied, in order to identify markers for the level of Botrytis resistance. Sensitivity of plants to Botrytis correlated well with the accumulation of the pathogen-related plant hormone jasmonic acid and the activity of the defense-related enzyme glucanase. Moreover, the accumulation patterns of a large number of genes and metabolites, many of which have not been described before, coincided with either Botrytis infection, chemical-pretreatment or plant resistance level. These genes and metabolites are thus potential markers for infection of and plant resistance to Botrytis.
However, the robustness and generic use of the detected markers need to be verified in independent follow-up experiments, for instance using other plant species or varieties as well as other Botrytis strains.