title: Analysis of expressed sequence tags from the Huperzia serrata leaf for gene discovery in the areas of secondary metabolite biosynthesis and development regulation.
abstract: Huperzia serrata produces various types of lycopodium alkaloids, especially the huperzine A (HupA) that is a promising drug candidate for Alzheimer's disease. Despite the medicinal importance of H. serrata, little genomic or transcriptomic data are available from the public databases. A cDNA library was thus generated from RNA isolated from the leaves of H. serrata. A total of 4012 clones were randomly selected from the library, and 3451 high-quality expressed sequence tags (ESTs) were assembled to yield 1510 unique sequences with an average length of 712 bp. The majority (79.4%) of the unique sequences were assigned to the putative functions based on the BLAST searches against the public databases. The functions of these unique sequences covered a broad set of molecular functions, biological processes and biochemical pathways according to GO and KEGG assignments. The transcripts involved in the secondary metabolite biosynthesis of alkaloids, terpenoids and flavone/flavonoids, such as cytochrome P450, lysine decarboxylase (LDC), flavanone 3-hydroxylase, squalene synthetase and 2-oxoglutarate 3-dioxygenase, were well represented by 34 unique sequences in this EST dataset. The corresponding peptide sequence of the LDC contained the Pfam 03641 domain and was annotated as a putative LDC. The unique sequences encoding transcription factors, phytohormone biosynthetic enzymes and signaling components were also found in this EST collection. In addition, a total of 501 potential SSR-motif microsatellite loci were identified from the 393 H. serrata leaf unique sequences. This set of non-redundant ESTs and the molecular markers obtained in this study will establish valuable resources for a wide range of applications including gene discovery and identification, genetic mapping and analysis of genetic diversity, cultivar identification and marker-assisted selections in this important medicinal plant.
authors.affiliation: Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences & Peking Union Medical College, No. 151, Malianwa North Road, HaiDian District, Beijing 100193, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Luo
authors.forename: Chao
authors.initials: C
authors.lastname: Sun
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Song
authors.forename: Deli
authors.initials: D
authors.lastname: Wang
authors.forename: Xiaocheng
authors.initials: X
authors.lastname: Jia
authors.forename: Rongtao
authors.initials: R
authors.lastname: Li
authors.forename: Shilin
authors.initials: S
authors.lastname: Chen
mesh_terms: D018076:DNA, Complementary; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant; D032501:Huperzia / Q000235:genetics* / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary