Enhanced cold tolerance in transgenic tobacco expressing a chloroplast ω-3 fatty acid desaturase gene under the control of a cold-inducible promoter
Enhanced cold tolerance in transgenic tobacco expressing a chloroplast ω-3 fatty acid desaturase gene under the control of a cold-inducible promoter
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DOI：
10.1007/s00425-005-0161-4
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发表时间：
2006-04-01
期刊：
影响因子：
4.3
通讯作者：
Li, Y
中科院分区：
文献类型：
--
作者：
Khodakovskaya, M;McAvoy, R;Li, Y
利用拟南芥冷诱导启动子(Cor15a)控制下的叶绿体特异的omega-3-脂肪酸脱氢酶基因(FAD7)克隆了一个新的冷诱导基因结构。RT-PCR证实了FAD7在幼龄烟草中的表达显著增加。哈瓦那)含有cor15a-fad7的植物，在短期暴露于寒冷之后。在低温(0.5℃、2℃或3.5℃)下培养44天后，转cor15a-FAD7基因烟草幼苗的存活率(40.2-96%)远高于野生型(6.7-10.2%)。此外，在长期冷藏条件下，低温诱导的cor15a-FAD7烟草植株中的主要三烯脂肪酸种类保持稳定，而野生型植株中的十六碳三烯酸(16：3)和十八碳三烯酸(18：3)的含量在相同条件下分别下降了79%和20.7%。电子显微镜观察表明，转cor15a-FAD7基因植株的叶绿体膜超微结构不受长期低温胁迫的影响。相反，野生型植物在相同的条件下经历了颗粒堆积和类囊体膜的解体。膜完整性的变化与野生型植物叶片叶绿素浓度的急剧下降和低成活率相一致。低温诱导的双转基因拟南针。同时携带cor15a-fad7耐冷基因和cor15a-ipt耐暗基因的植株，在2℃黑暗条件下的长期冷藏条件下，其存活率(-90%)显著高于野生型植株(2%)。
A new cold-inducible genetic construct was cloned using a chloroplast-specific omega-3-fatty acid desaturase gene (FAD7) under the control of a cold-inducible promoter (cor15a) from Arabidopsis thaliana. RT-PCR confirmed a marked increase in FAD7 expression, in young Nicotiana tabacum (cv. Havana) plants harboring cor15a-FAD7, after a short-term exposure to cold. When young, cold-induced tobacco seedlings were exposed to low-temperature (0.5, 2 or 3.5 degrees C) for up to 44 days, survival within independent cor15a-FAD7 transgenic lines (40.2-96%) was far superior to the wild type (6.7-10.2%). In addition, the major trienoic fatty acid species remained stable in cold-induced cor15a-FAD7 N. tabacum plants under prolonged cold storage while the levels of hexadecatrienoic acid (16:3) and octadecatrienoic acid (18:3) declined in wild type plants under the same conditions (79 and 20.7% respectively). Electron microscopy showed that chloroplast membrane ultrastructure in cor15a-FAD7 transgenic plants was unaffected by prolonged exposure to cold temperatures. In contrast, wild type plants experienced a loss of granal stacking and disorganization of the thylakoid membrane under the same conditions. Changes in membrane integrity coincided with a precipitous decline in leaf chlorophyll concentration and low survival rates in wild type plants. Cold-induced double transgenic N. alata (cv. Domino Mix) plants, harboring both the cor15a-FAD7 cold-tolerance gene and a cor15a-IPT dark-tolerance gene, exhibited dramatically higher survival rates (89-90%) than wild type plants (2%) under prolonged cold storage under dark conditions (2 degrees C for 50 days).