青钱柳叶片转录组数据组装及基因功能注释

De novo transcriptome assembly and annotation of the leaves of Cyclocaryapaliurus

青钱柳是一种民间常用中药,青钱柳叶中有多种生物活性的次生代谢物,如有机酸、黄酮类、皂苷类、铱类、精油、无机元素等,但对于青钱柳次生代谢产物合成的分子机制仍未见有报道.使用Illumina公司Hiseq 4000平台对青钱柳叶进行转录组测序,对reads进行拼接,得到50126个unigenes平均长度为1 247bp,有19 875 (39.65%)unigenes由NCBI非冗余数据库进行注释的,23 716 (47.31%)unigenes被注释到GO数据库,14 950个(29.82%)unigenes匹配到COG功能组.进一步的分析结果显示,6 012 (11.20%)个unigenes被富集到254个KEGG代谢通路,其中1 212个unigenes参与了次生代谢产物的生物合成,并且发现126个unigenes参与异戊二烯代谢,包括萜烯类、香茅醛、呋喃酮、苷的代谢途径.此外,总共检测到21 089个简单序列重复(SSRs).通过对老叶与嫩叶的转录组比较分析结果显示,在青钱柳不同生长发育时期的叶片中,基因表达上调占主异作用的过程主要涉及萜类和多肽的代谢、辅酶和维生素的代谢和氨基酸代谢,而基因表达下调占主异作用的过程主要涉及信号传输、类脂物代谢与能量代谢.该转录组数据可为青钱柳重要生物活性成分的生物合成和调控提供参考.

Cyclocaryapaliurus are widely used as a traditional Chinese medicine.There are various bioactive secondary metabolites especially in the flowers of Cyclocaryapaliurus,such as organic acids,flavones,saponins,iridoids,essential oil,and inorganic elements.The molecular mechanism for the differences is poorly understood so far.In thepresent paper,the transcriptome of Cyclocaryapaliurus leaves was sequenced using Illumina Hiseq 4000 platform,and 50,126 unigenes were generated with an average length of 1,247 bp.19,875(39.65%)unigenes were annotated by NCBI Non-Redundant database,and 23,716(47.31%)unigenes were classified into Gene Ontology(GO)database,along with 14,950(29.82%)unigenes assigned to Clusters of Orthologous Group(COG)categories.Further analysis results showed 6,012(11.20%)unigenes were mapped onto 254 pathways in Kyoto Encyclopedia of Genes and Genomes(KEGG),among which 1,212 unigenes were identified to be involved in biosynthesis of secondary metabolites.It was also found that 126 unigenes are involved in the metabolism of isoprene,including the metabolic pathways of terpenes,citronellal,furanones and glycosides.In addition,a total of 21,089 putative simple sequence repeats(SSRs)were detected.The results of transcriptome analysis of old leaves and young leaves showed that the up-regulation of gene expression in the leaves of Cyclocaryapaliurus is involved in the metabolism of steroids,peptides,coenzymes,vitamins and amino acid,while the down-regulation of gene expression is mainly related to signal transmission,lipid metabolism and energy metabolism.This transcriptome dataset might provide some references to understand the biosynthesis and regulation of important bioactive components in Cyclocaryapaliurus.