Hamada T, Kodama H, Takeshita K, Utsumi H, Iba K
Department of Biology, Faculty of Science, Kyushu University, Fukuoka 812-8581, Japan (T.H., H.K., K.I.).
Plant Physiol. 1998 Oct;118(2):591-8. doi: 10.1104/pp.118.2.591.
Microsomal omega-3 fatty acid desaturase catalyzes the conversion of 18:2 (linoleic acid) to 18:3 (alpha-linolenic acid) in phospholipids, which are the main constituents of extrachloroplast membranes. Transgenic tobacco (Nicotiana tabacum) plants with increased 18:3 contents (designated SIIn plants) were produced through the introduction of a construct with the tobacco microsomal omega-3 fatty acid desaturase gene under the control of the highly efficient promoter containing the E12Omega sequence. 18:3 contents in the SIIn plants were increased by about 40% in roots and by about 10% in leaves compared with the control plants. With regard to growth at 15 degreesC and 25 degreesC and the ability to tolerate chilling at 1 degreesC and 5 degreesC, there were no discernible differences between the SIIn and the control plants. Freezing tolerance in leaves and roots, which was assessed by electrolyte leakage, was almost the same between the SIIn and the control plants. The fluidity of plasma membrane from the SIIn plants was almost the same as that of the control plants. These results indicate that an increase in the 18:3 level in phospholipids is not directly involved in compensation for the diminishment in growth or membrane properties observed under low temperatures.
微粒体ω-3脂肪酸去饱和酶催化磷脂中18:2（亚油酸）向18:3（α-亚麻酸）的转化，磷脂是叶绿体外膜的主要成分。通过导入一个构建体来培育18:3含量增加的转基因烟草（烟草）植株（命名为SIIn植株），该构建体含有受含E12Omega序列的高效启动子控制的烟草微粒体ω-3脂肪酸去饱和酶基因。与对照植株相比，SIIn植株根部的18:3含量增加了约40%，叶片中的增加了约10%。在15℃和25℃下的生长情况以及在1℃和5℃下耐受低温的能力方面，SIIn植株和对照植株之间没有明显差异。通过电解质渗漏评估的叶片和根部的抗冻性，SIIn植株和对照植株几乎相同。SIIn植株质膜的流动性与对照植株几乎相同。这些结果表明，磷脂中18:3水平的增加与补偿低温下观察到的生长或膜特性的降低没有直接关系。
