Saccharomyces cerevisiae strain expressing a plant fatty acid desaturase produces polyunsaturated fatty acids and is susceptible to oxidative stress induced by lipid peroxidation.

While oxygen is essential for aerobic organisms, it also forms potentially harmful reactive oxygen species. For its simplicity, easy manipulation and cultivation conditions, yeast is used as a model in oxidative stress research. However, lack of polyunsaturated fatty acids in yeast membranes makes yeast unsuitable for research in the field of lipid peroxidation. Therefore, we have constructed a yeast strain expressing a Δ 12 desaturase gene from the tropical rubber tree, Hevea brasiliensis. This yeast strain expressed the heterologous desaturase in an active form and, consequently, produced Δ 9/Δ 12 polyunsaturated fatty acids under inducing conditions. The presence of polyunsaturated fatty acids changed the yeast’ s sensitivity to oxidative stress induced by addition of hydrogen peroxide. This difference in sensitivity was followed by the formation of 4-hydroxy-2-nonenal, one of the end products of linoleic fatty acid peroxidation, which is known to play a role in cell growth control and signaling. Here we show that this yeast strain conditionally expressing the Δ 12 desaturase gene provides a novel and well defined eukaryotic model in lipid peroxidation research. Its potential to investigate the molecular basis of responses to oxidative stress, in particular the involvement of reactive aldehydes derived from fatty acid peroxidation, especially 4-hydroxy-2-nonenal, will be addressed.