作 者：
刘祾悦;阮成江;王莉;张莞晨;王海明;吴波;闫蕊
单 位：
大连民族大学资源植物研究所生物技术与资源利用教育部重点实验室
关键词：
文冠果;种仁油脂;神经酸;qRT-PCR;多基因协同调控
摘 要：
文冠果是中国北方重要的木本油料树种,种仁油脂富含油酸、亚油酸,特别是含有3%～5%其他食用植物油缺乏的神经酸。为探讨文冠果种仁油脂脂肪酸形成的基因调控机制,以品系‘12-03’4个不同发育期(6月22日, 7月6日, 7月19日, 8月1日)的种仁为材料,利用GC-TOF/MS (气相色谱飞行时间质谱)方法测定种仁油脂脂肪酸组份及不同组份的相对百分比;利用q RT-PCR分析种仁油脂脂肪酸形成相关基因KAR、EAR、HAD、FATA、FATB、SAD、FAE1、KCR、HCD、ECR、FAD2和FAD3的表达模式;分析不同基因表达对种仁油脂脂肪酸形成积累的影响。结果表明:(1)品系‘12-03’种仁成熟期油脂中油酸占29.87%、亚油酸占42.96%、神经酸占3.27%;种仁发育期间,油酸含量呈一直上升趋势,亚油酸含量呈先下降后上升趋势,神经酸呈先上升后下降趋势。(2) KAR、HAD和EAR基因的高表达协同FATA和FATB基因的低表达,为文冠果种仁油脂碳十八以上不饱和脂肪酸的形成积累提供了充足硬脂酸合成前体C16:0-ACP。(3)种仁成熟期前的SAD基因高表达催化硬脂酸快速去饱和为油酸,为C18:1以上不饱和脂肪酸形成提供了充足底物。(4)不同发育期种仁中FAE代谢通路的FAE1和KCR基因表达量均较低,HCD基因表达量在种仁成熟期前呈快速上升趋势;HCD基因是文冠果神经酸合成FAE代谢通路上的关键基因。(5)种仁发育期FAD2基因的持续高表达和FAD3基因的持续低表达促成种仁高积累亚油酸和低积累亚麻酸。SAD和FAD2基因的协同高表达促成文冠果种仁油脂富含油酸和亚油酸,而种仁成熟前期不断上升的HCD基因表达量促进了神经酸的合成积累。这不仅可为进一步理解文冠果种仁油脂脂肪酸合成积累的基因调控提供理论依据,而且对木本油料脂肪酸的遗传改良具有重要意义。
译 名：
Coordinated Regulation of Multigenes Formed by Fatty Acids in Kernel Oil of Xanthoceras sorbifolium
作 者：
Liu Lingyue;Ruan Chengjiang;Wang Li;Zhang Wanchen;Wang Haiming;Wu Bo;Yan Rui;Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Institute of Plant Resources, Dalian Minzu University;
单 位：
Wang Yucai%Wang Huajun%Ma Xiaole%Li Baochun%Si Erjing%Wang Juncheng%Yao Lirong%Ma Zengke%Meng Yaxiong%Gansu Provincial Key Laboratory of Arid Land Crop Science, Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement%College of Agronomy, Gansu Agricultural University%College of Life Sciences and Technology, Gansu Agricultural University
关键词：
Xanthoceras sorbifolium;;Kernel oil;;Nervonic acid;;qRT-PCR;;Coordinated regulation of multigenes
摘 要：
Xanthoceras sorbifolium is an important woody oil tree in north of China, its kernel oil contains rich oleic acid and linoleic acid, especially, it contains 3%～5% nervonic acids, which is lack for other edible vegetable oils. In order to study regulation mechanism of genes on the formation of fatty acids in kernel oil of X. sorbifolium,this study took the kernel with different developmental phase(June 22, July 6, July 19, and August 1) as materials.Measured the relative percentage of fatty acid composition of kernel oil and other compositions. The expression patterns of KAR, EAR, HAD, FATA, FATB, SAD, FAE1, KCR, HCD, ECR, FAD2 and FAD3 genes involved in fatty acid biosynthesis were tested using qRT-PCR analysis, and the effects of their expression on the biosynthesis and accumulation of fatty acids were analyzed. The result showed that:(1) for oils extracted mature kernels of line‘12-03', the oleic acid was about 29.87%, the linoleic acid was about 42.96% and the nervonic acid was about 3.27%. During kernel development, the relative contents of oleic acid had shown an up-trend, the relative contents of linoleic acid were firstly decreased but then increased, and the relative contents of nervonic acid were first increased but then decreased.(2) The high expressions of KAR, HAD and EAR genes with the low expressions of FATA and FATB genes provided enough C16:0-ACP precursor of biosynthesis of C18:0, which was ma terials for biosynthesis of more than carbon eighteen unsaturated fatty acids.(3) Before kernel maturity, the high expressions of SAD gene promoted the catalyses of stearic acid desaturation to oleic acid, which provided enough materials for the biosynthesis of unsaturated fatty acid of over C18:1.(4) For kernels of different developmental stages, the expressions of FAE1 and KCR genes in the FAE metabolic pathway were relative low, and the expressions of HCD genes had shown an up-trend before kernel maturity. This showed that the HCD gene was the key gene of nervonic acid biosynthesis.(5) The high expressions of FAD2 gene and the low expressions of FAD3 gene at developing kernels contributed to high accumulation of linoleic acid and low accumulation of linolenic acid in kernel oils. The high accumulation of oleic acid and linoleic acid was from high co-expressions of SAD and FAD2 genes in the kernel of X. sorbifolium, and the increasing HCD gene expression before kernel maturation promoted biosynthesis and accumulation of nervonic fatty acid. These results might provide scientific basis for understanding the gene regulation of biosynthesis and accumulation of fatty acids in tree oils, which is significant for genetic improvement of important fatty acids in woody oils trees.
