作者：中科院西北生態(tài)環(huán)境資源研究所石玉蘭、蘭州大學(xué)生科院安黎哲

標(biāo)題：Integrated regulation triggered by a cryophyte -3 desaturase gene confers multiple-stress tolerance in tobacco

主題： -3脂肪酸去飽和酶在植物脅迫耐受中的功能

期刊：Journal of Experimental Botany

影響因子：5.354

檢測(cè)指標(biāo)：Ca2+

英文摘要

-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 -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（谷歌機(jī)翻）

-3脂肪酸去飽和酶（FADs）被認(rèn)為主要通過(guò)亞麻酸（C18：3）誘導(dǎo)的膜穩(wěn)定作用促進(jìn)植物抗逆性，但缺乏對(duì)其在脅迫適應(yīng)中的作用的綜合分析。

在這里，我們從冷凍植物（Chorispora bungeana）中分離出微粒體 -3 FAD基因（CbFAD3），并闡明其在脅迫耐受中的功能。表現(xiàn)出與擬南芥AtFAD3高度同一性的CbFAD3被非生物脅迫上調(diào)。其功能通過(guò)酵母中的異源表達(dá)來(lái)驗(yàn)證。煙草中CbFAD3的過(guò)量表達(dá)在葉和根中組成性地增加了C18：3，這保持了膜的流動(dòng)性，并增強(qiáng)了植物對(duì)冷，干旱和鹽脅迫的耐受性。

值得注意的是，組成型增加的C18：3誘導(dǎo)質(zhì)膜Ca2+-ATPase的持續(xù)活化，從而改變應(yīng)激誘導(dǎo)的Ca2+信號(hào)傳導(dǎo)。與C18：3水平正相關(guān)的活性氧（ROS）清除系統(tǒng)也在轉(zhuǎn)基因系中被激活。

微陣列分析顯示過(guò)表達(dá)CbFAD3的植物增加了應(yīng)激反應(yīng)基因的表達(dá)，其中大多數(shù)受C18：3，Ca2+或ROS的影響。 CbFAD3一起通過(guò)C18：3誘導(dǎo)的膜，Ca2+，ROS和應(yīng)激反應(yīng)基因的整合調(diào)節(jié)賦予對(duì)煙草中多種脅迫的耐受性。這與先前的觀察結(jié)果形成對(duì)比，之前的觀察結(jié)果僅僅將壓力耐受性歸因于膜穩(wěn)定。

Ca2+ fluxes in root tips treated with 15% PEG or 200 mM NaCl (n=10 ten-day-old seedling roots).

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