Jiang Yusong, Liao Qinhong, Zou Yong, Liu Yiqing, Lan Jianbin
Research Institute for Special Plants, Chongqing University of Arts and Sciences, Chongqing, 402160, China.
Bot Stud. 2017 Oct 23;58(1):41. doi: 10.1186/s40529-017-0195-5.
Ginger (Zingiber officinale Rosc.) is a popular flavoring that widely used in Asian, and the volatile oil in ginger rhizomes adds a special fragrance and taste to foods. The bioactive compounds in ginger, such as gingerols, diarylheptanoids, and flavonoids, are of significant value to human health because of their anticancer, anti-oxidant, and anti-inflammatory properties. However, as a non-model plant, knowledge about the genome sequences of ginger is extremely limited, and this limits molecular studies on this plant. In this study, de novo transcriptome sequencing was performed to investigate the expression of genes associated with the biosynthesis of major bioactive compounds in matured ginger rhizome (MG), young ginger rhizome (YG), and fibrous roots of ginger (FR).
A total of 361,876 unigenes were generated by de novo assembly. The expression of genes involved in the pathways responsible for the biosynthesis of major bioactive compounds differed between tissues (MG, YG, and FR). Two pathways that give rise to volatile oil, gingerols, and diarylheptanoids, the "terpenoid backbone biosynthesis" and "stilbenoid, diarylheptanoid and gingerol biosynthesis" pathways, were significantly enriched (adjusted P value < 0.05) for differentially expressed genes (DEGs) (FDR < 0.005) both between the FR and YG libraries, and the FR and MG libraries. Most of the unigenes mapped in these two pathways, including curcumin synthase, phenylpropanoylacetyl-CoA synthase, trans-cinnamate 4-monooxygenase, and 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase, were expressed to a significantly higher level (log (fold-change) ≥ 1) in FR than in YG or MG.
This study provides the first insight into the biosynthesis of bioactive compounds in ginger at a molecular level and provides valuable genome resources for future molecular studies on ginger. Moreover, our results establish that bioactive compounds in ginger may predominantly synthesized in the root and then transported to rhizomes, where they accumulate.
生姜（Zingiber officinale Rosc.）是一种广受欢迎的调味料，在亚洲广泛使用，姜根茎中的挥发油为食物增添了特殊的香气和味道。生姜中的生物活性化合物，如姜辣素、二芳基庚烷类化合物和黄酮类化合物，因其抗癌、抗氧化和抗炎特性，对人类健康具有重要价值。然而，作为一种非模式植物，关于生姜基因组序列的知识极其有限，这限制了对该植物的分子研究。在本研究中，进行了从头转录组测序，以研究成熟姜根茎（MG）、幼嫩姜根茎（YG）和姜须根（FR）中与主要生物活性化合物生物合成相关基因的表达情况。
通过从头组装共产生了361,876个单基因。参与主要生物活性化合物生物合成途径的基因在不同组织（MG、YG和FR）中的表达存在差异。两条产生挥发油、姜辣素和二芳基庚烷类化合物的途径，即“萜类骨架生物合成”和“芪类、二芳基庚烷类和姜辣素生物合成”途径，在FR与YG文库以及FR与MG文库之间的差异表达基因（DEGs）（FDR < 0.005）中均显著富集（校正P值 < 0.05）。这两条途径中映射的大多数单基因，包括姜黄素合酶、苯丙酰乙酰辅酶A合酶、反式肉桂酸4-单加氧酶和4-羟基-3-甲基丁-2-烯-1-基二磷酸合酶，在FR中的表达水平显著高于YG或MG（log（倍数变化）≥ 1）。
本研究首次在分子水平上揭示了生姜中生物活性化合物的生物合成，并为未来生姜的分子研究提供了有价值的基因组资源。此外，我们的结果表明，生姜中的生物活性化合物可能主要在根中合成，然后运输到根茎中积累。
