Project description:Fungal secondary metabolites can not only cause toxic effects in animals and humans, but also serve as virulence factors of the producing fungi for causing plant diseases.Thus, the severity of plant diseases associated with mycotoxins depend on the sensitivity towards the toxin. In previous experiments, we have evaluated the phytotoxic effect ofa mycotoxin on root growth of Arabidopsis wild-type and mutant seedlings. Mycotoxin treatment of a new conditional root expansion mutant partially restores the expansion phenotype (JE100; Werner et al., unpublished). AIM: This experiment aims to identify genes, in early and later phases after mycotoxin treatment in wild-type and mutant seedlings. EXPERIMENTAL PLAN: Eight Affymetrix chips are needed for this experiment. RNA preparation will be provided from wild-type, accession Columbia, and mutant seedlings after different time points of mycotoxin treatment. As control, separate seedlings will be treated with the same concentration of solvent (DMSO). Briefly, seeds will be sterilized, stratified for 48 hours and germinated on MS agar plates containing 4.5% sucrose at 22°C and 16h/8h light/dark cycles. 10 days after germination, seedlings will be transferred to liquid MS medium and shaken for another 3 days for acclimatization. Seedlings will be harvested after 2 and 24 hours of treatment with a single concentration (50 µM) of mycotoxin. To account for experimental variations (i.e. time needed for freezing the tissues, circadian clock,...), the experiment will be repeated three times and RNA samples will be pooled. EXPECTED RESULTS: The experiment should identify genes differentially expressed: 1) between wild-type and mutant seedlings, 2) upon mycotoxin treatment in wild-type, 3) upon mycotoxin treatment of mutant seedlings and 4) upon solvent treatment. The results will allow us to pinpoint the mode of action of this mycotoxin. They will also allow us to better understand the function of the mutated gene which affects the sensitivity towards the mycotoxin. Furthermore, we expect to identify the signaling pathway by which the plant responses towards the mycotoxinis triggered.
