Wang Meiling, Wang Yong, Wu Hongqi, Xu Jing, Li Tingting, Hegebarth Daniela, Jetter Reinhard, Chen Letian, Wang Zhonghua
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
Department of Botany, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
Sci Rep. 2016 Apr 26;6:25008. doi: 10.1038/srep25008.
Cuticular waxes play crucial roles in protecting plants against biotic and abiotic stresses. They are complex mixtures of very-long-chain fatty acids and their derivatives, including C20-C32 fatty alcohols. Here, we report the identification of 32 FAR-like genes and the detailed characterization of TaFAR2, TaFAR3 and TaFAR4, wax biosynthetic genes encoding fatty acyl-coenzyme A reductase (FAR) in wheat leaf cuticle. Heterologous expression of the three TaFARs in wild-type yeast and mutated yeast showed that TaFAR2, TaFAR3 and TaFAR4 were predominantly responsible for the accumulation of C18:0, C28:0 and C24:0 primary alcohols, respectively. Transgenic expression of the three TaFARs in tomato fruit and Arabidopsis cer4 mutant led to increased production of C22:0-C30:0 primary alcohols. GFP-fusion protein injection assay showed that the three encoded TaFAR proteins were localized to the endoplasmic reticulum (ER), the site of wax biosynthesis. The transcriptional expression of the three TaFAR genes was induced by cold, salt, drought and ABA. Low air humidity led to increased expression of TaFAR genes and elevated wax accumulation in wheat leaves. Collectively, these data suggest that TaFAR2, TaFAR3 and TaFAR4 encode active alcohol-forming FARs involved in the synthesis of primary alcohol in wheat leaf and the response to environmental stresses.
角质蜡在保护植物抵御生物和非生物胁迫方面发挥着关键作用。它们是非常长链脂肪酸及其衍生物的复杂混合物，包括C20 - C32脂肪醇。在此，我们报告了32个类FAR基因的鉴定以及TaFAR2、TaFAR3和TaFAR4的详细表征，这三个蜡生物合成基因在小麦叶片角质层中编码脂肪酰辅酶A还原酶（FAR）。这三个TaFAR基因在野生型酵母和突变酵母中的异源表达表明，TaFAR2、TaFAR3和TaFAR4分别主要负责C18:0、C28:0和C24:0伯醇的积累。这三个TaFAR基因在番茄果实和拟南芥cer4突变体中的转基因表达导致C22:0 - C30:0伯醇产量增加。GFP融合蛋白注射试验表明，三个编码的TaFAR蛋白定位于内质网（ER），即蜡生物合成的场所。这三个TaFAR基因的转录表达受冷、盐、干旱和脱落酸诱导。低空气湿度导致TaFAR基因表达增加以及小麦叶片蜡积累升高。总体而言，这些数据表明TaFAR2、TaFAR3和TaFAR4编码参与小麦叶片伯醇合成及对环境胁迫响应的活性醇形成FAR。
