Pyrosequencing of the Camptotheca acuminata transcriptome reveals putative genes involved in camptothecin biosynthesis and transport

BMC Genomics

Research Article

Enzo Tramontano¹  Aiping Lv²  Hongmei Luo³  Chao Sun³  Liang Dong³  Shilin Chen³  Ying Li³  Jingyuan Song³  Yunyun Niu³  Yingjie Zhu³  Yongzhen Sun³ 

[1] Department of Applied Sciences in Biosystems, University of Cagliari, Monserrato (Cagliari), Italy;Institute of Basic Theory, China Academy of Traditional Chinese Medicine, Beijing, China;The Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, 100193, Beijing, P. R. China;

关键词: Glandular Trichome;    Terpenoid Indole Alkaloid;    Secologanin;    Camptotheca Acuminata;    Terpenoid Indole Alkaloid Pathway;   

DOI  :  10.1186/1471-2164-12-533

 received in 2011-03-22, accepted in 2011-10-30,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundCamptotheca acuminata is a Nyssaceae plant, often called the "happy tree", which is indigenous in Southern China. C. acuminata produces the terpenoid indole alkaloid, camptothecin (CPT), which exhibits clinical effects in various cancer treatments. Despite its importance, little is known about the transcriptome of C. acuminata and the mechanism of CPT biosynthesis, as only few nucleotide sequences are included in the GenBank database.ResultsFrom a constructed cDNA library of young C. acuminata leaves, a total of 30,358 unigenes, with an average length of 403 bp, were obtained after assembly of 74,858 high quality reads using GS De Novo assembler software. Through functional annotation, a total of 21,213 unigenes were annotated at least once against the NCBI nucleotide (Nt), non-redundant protein (Nr), Uniprot/SwissProt, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Arabidopsis thaliana proteome (TAIR) databases. Further analysis identified 521 ESTs representing 20 enzyme genes that are involved in the backbone of the CPT biosynthetic pathway in the library. Three putative genes in the upstream pathway, including genes for geraniol-10-hydroxylase (CaPG10H), secologanin synthase (CaPSCS), and strictosidine synthase (CaPSTR) were cloned and analyzed. The expression level of the three genes was also detected using qRT-PCR in C. acuminata. With respect to the branch pathway of CPT synthesis, six cytochrome P450s transcripts were selected as candidate transcripts by detection of transcript expression in different tissues using qRT-PCR. In addition, one glucosidase gene was identified that might participate in CPT biosynthesis. For CPT transport, three of 21 transcripts for multidrug resistance protein (MDR) transporters were also screened from the dataset by their annotation result and gene expression analysis.ConclusionThis study produced a large amount of transcriptome data from C. acuminata by 454 pyrosequencing. According to EST annotation, catalytic features prediction, and expression analysis, novel putative transcripts involved in CPT biosynthesis and transport were discovered in C. acuminata. This study will facilitate further identification of key enzymes and transporter genes in C. acuminata.

【 授权许可】

Unknown   
© Sun et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.