Effects of cold treatment on Arabidopsis thaliana : a study in the change of gene expression levels in some selected COR-genes and composition of important cell membrane lipids of A. thaliana

Sammanfattning: The effect of cold stress in Arabidopsis thaliana, mouse cress, was examined. The object was to investigate how gene expression and membrane lipid configuration was affected in seedlings when being treated with low temperature. According to several studies, the fatty acid composition changes to being less saturated in several important cell membrane lipid classes during prolonged cold. Several cold regulated; so called COR-genes were chosen, to investigate their presumed change in gene expression levels after cold treatment. Roughly 1000 plants of A. thaliana were established from seeds in liquid nutrient medium in ten flasks and were grown under artificial light and 20 °C for 10 days. Then half of the seedlings were treated by putting the flasks on ice for 6 hours. Control and treatment samples went through lipid extraction and gas chromatography, as well as RNA extraction, complementary DNA synthesis and quantitative PCR. The results are ambiguous. Regarding cell membrane lipids, only a minor decrease from saturated to unsaturated fatty acids of around 6-10% could be measured for some membrane lipid classes. Concerning gene expression levels, the levels vary from being 1.1 to 2.5 times greater in treated samples, compared to control samples.