益智不同组织多糖含量及其生物合成途径分析

Analysis of Polysaccharide Content and Biosynthesis Pathway in Different Tissues of Alpinia oxyphylla

摘要:

为了解益智（Alpinia oxyphylla）多糖生物合成途径关键酶功能，对其茎、叶、果实中的多糖含量及其单糖组成进行了研究，并采用Real-Time qPCR分析了益智多糖生物合成关键酶基因的表达模式。结果表明，益智多糖含量依次为果实 > 叶 > 茎，主要由葡萄糖、木糖、甘露糖、半乳糖和阿拉伯糖组成；利用益智转录组数据共获得47 690条unigenes，其中31 892条在NR、Swiss-Prot、KEGG、COG、KOG、GO和Pfam数据库获得注释，其中208个unigenes参与益智多糖的生物合成，涉及15个酶。表达分析表明，所筛选的18个基因在茎、叶、果实中均有表达，14个基因在果实中的表达量最高，以糖基转移酶基因和UDP-葡萄糖焦磷酸化酶基因的表达量最高，且其表达模式与不同组织中葡萄糖含量的变化一致。

关键词:益智;多糖;转录组;糖基转移酶

Abstract:

To understand the key enzyme functions of polysaccharide biosynthesis pathway in Alpinia oxyphylla, the polysaccharides contents in stems, leaves and fruits and monosaccharide composition were studied, and the expression pattern of key enzyme genes involved in the biosynthetic pathway of polysaccharide was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). The results showed that the polysaccharides contents in different tissues was in the order of fruit > leaf > stem. The polysaccharide was consist of glucose, xylose, mannose, galactose and arabinose. A total of 47 690 unigenes were obtained from A. oxyphylla transcriptome database, of which 31 892 were annotated in NR, Swiss-Prot, KEGG, COG, KOG, GO and Pfam databases. Among them, 208 of unigenes encoding 18 enzymes were involved in the biosynthesis of A. oxyphylla polysaccharide. Furthermore, all of 18 selected unigenes were expressed in stems, leaves and fruits, of which 14 unigenes showed the highest expression in fruit. Interestingly, two genes, encoding glycosyltransferase and UDP glucose pyrophosphorylase, exhibited the highest expression, and their expressions were consistent with the glucose content in different tissues of A. oxyphylla.

Key words:Alpinia oxyphylla;Polysaccharide;Transcriptome;Glycosyltransferase