作者：中科院西北生态环境资源研究所石玉兰、兰州大学生科院安黎哲
标题：integrated regulation triggered by a cryophyte ω-3 desaturase gene confers multiple-stress tolerance in tobacco
主题：ω-3脂肪酸去饱和酶在植物胁迫耐受中的功能
期刊：journal of experimental botany
影响因子：5.354
检测指标：ca2+
英文摘要
ω-3 fatty acid desaturases (fads) are thought to contribute to plant stress tolerance mainly through linolenic acid (c18:3)-induced membrane stabilization, but a comprehensive analysis of their roles in stress adaptation is lacking.
here, we isolated a microsomal ω-3 fad gene (cbfad3) from a cryophyte (chorispora bungeana) and elucidated its functions in stress tolerance. cbfad3, exhibiting a high identity to arabidopsis atfad3, was up-regulated by abiotic stresses. its functionality was verified by heterogonous expression in yeast. overexpression of cbfad3 in tobacco constitutively increased c18:3 in both leaves and roots, which maintained the membrane fluidity, and enhanced plant tolerance to cold, drought, and salt stresses.
notably, the constitutively increased c18:3 induced a sustained activation of plasma membrane ca2+-atpase, thereby, changing the stress induced ca2+ signaling. the reactive oxygen species (ros) scavenging system, which was positively correlated with the level of c18:3, was also activated in the transgenic lines.
microarray analysis showed that cbfad3-overexpressing plants increased the expression of stressresponsive genes, most of which are affected by c18:3, ca2+, or ros. together, cbfad3 confers tolerance to multiple stresses in tobacco through the c18:3-induced integrated regulation of membrane, ca2+, ros, and stress-responsive genes. this is in contrast with previous observations that simply attribute stress tolerance to membrane stabilization.
中文摘要（谷歌机翻）
ω-3脂肪酸去饱和酶（fads）被认为主要通过亚麻酸（c18：3）诱导的膜稳定作用促进植物抗逆性，但缺乏对其在胁迫适应中的作用的综合分析。
在这里，我们从冷冻植物（chorispora bungeana）中分离出微粒体ω-3 fad基因（cbfad3），并阐明其在胁迫耐受中的功能。表现出与拟南芥atfad3高度同一性的cbfad3被非生物胁迫上调。其功能通过酵母中的异源表达来验证。烟草中cbfad3的过量表达在叶和根中组成性地增加了c18：3，这保持了膜的流动性，并增强了植物对冷，干旱和盐胁迫的耐受性。
值得注意的是，组成型增加的c18：3诱导质膜ca2+-atpase的持续活化，从而改变应激诱导的ca2+信号传导。与c18：3水平正相关的活性氧（ros）清除系统也在转基因系中被激活。
微阵列分析显示过表达cbfad3的植物增加了应激反应基因的表达，其中大多数受c18：3，ca2+或ros的影响。 cbfad3一起通过c18：3诱导的膜，ca2+，ros和应激反应基因的整合调节赋予对烟草中多种胁迫的耐受性。这与先前的观察结果形成对比，之前的观察结果仅仅将压力耐受性归因于膜稳定。
ca2+ fluxes in root tips treated with 15% peg or 200 mm nacl (n=10 ten-day-old seedling roots).