小叶女贞叶片转录组研究

Transcriptome Analysis on Leaf of Ligustrum Quihoui Carr.

关键词:  小叶女贞  转录组  高通量测序  基因注释  SSR分析

Key words:  Ligustrum quihoui Carr.  transcriptome  high-throughout sequencing  gene annotation  SSR analysis

摘要:

目的 探讨小叶女贞中化学成分生物合成的遗传基础。方法 采用Illumina/Solexa Hiseq 2000测序平台在转录水平上对小叶女贞叶片进行高通量测序，结合生物信息学方法开展基因功能注释和SSR位点搜索。结果 共获得4 907 020 800个clean reads，含4.90 Gb的有效数据。利用生物信息学对clean reads进行拼接和组装共获得157 450条Unigene，总长度、平均长度和N₅₀分别为115.49 Mb，734 bp和1 510 bp。进一步进行基因功能预测，在GO数据库中共有17 756条Unigene可被分别注释到细胞组分、分子功能和生物学过程3大类别中，将Unigene与COG数据库进行比对，可获得25个功能类别，其中大部分Unigene与叶片中物质的合成与转运相关。在KEGG数据库中进行搜索比对，Unigene可定位到21类代谢途径中，涉及重要次生代谢产物苯丙素类、黄酮类和萜类生成的Unigene数目分别为860，216和806条。利用SSR分析软件，在所有的Unigene中共搜索到17 593个SSR位点，重复类型以二核苷酸为主。结论 本研究首次对小叶女贞转录组进行测序分析，获得的参与次生代谢的关键基因可为研究小叶女贞药用成分的生物合成和调控机制研究奠定基础。

Abstract:

OBJECTIVE To explore the genetic basis of the biosynthesis of the ingredients in Ligustrum quihoui Carr.. METHODS The high throughout sequencing was used to sequence the transcriptome in leaf of Ligustrum quihoui Carr.. by Illumina/Solexa Hiseq 2000. Gene function annotation and SSR site search were carried out in combination with bioinformatics methods. RESULTS The total of 4 907 020 800 clean reads was obtained including 4.90 Gb valid data. Based on the bioinformatics analysis, 157 450 Unigenes were received with the total read length of 115.49 Mb, the average read length of 734 bp and N₅₀ of 1 510 bp. Further functional classification indicate that 17 756 Unigenes were classified into cellular components, molecular functions and biological processes in GO database. Aligning Unigenes with COG database, 25 functional categories could be obtained, among which lots of Unigenes involved in nutritional function of leaf to synthesize and transport substances. As the search object, Unigene could be located into 21 kinds of metabolic pathways in KEGG database, in which the number of Unigene involved in the production of important secondary phenylpropanoid, metabolites flavonoids and terpenoids was 860, 216 and 806. The 17 593 SSRs were found by SSR analysis software and the highest frequency was di-nucleotide repents. CONCLUSION This study is the first comprehensive study on transcriptome of Ligustrum quihoui Carr.. The key genes involved in secondary metabolism can lay the foundation for studying the mechanism of biosynthesis and regulation of medicinal components of Ligustrum quihoui Carr..