Trienoic fatty acids and plant tolerance of temperature

The biomembrane of plant cells contains a high content of highly unsaturated fatty acids (polyunsaturated fatty acids) referred to as trienoic fatty acids. Although the amount of trienoic fatty acids varies according to the living environment of the plant, plants having a high ability to tolerate low temperatures, such as wheat, increase the amount of trienoic fatty acids to account for more than 80% of all fatty acids contained in the biomembrane when acclimated to low temperatures. On the other hand, some plants that thrive in deserts and other hot, dry regions demonstrate a remarkable decrease in the amount of trienoic fatty acids in high-temperature environments. On the basis of these findings, trienoic fatty acids are considered to be intimately involved in plant temperature tolerance. We have created plants, using genetic engineering techniques, with an excellent temperature tolerance by inhibiting the activity of ω-3 fatty acid desaturase, an enzyme which synthesizes trienoic fatty acids.