title: Transcriptome analysis reveals putative genes involved in iridoid biosynthesis in Rehmannia glutinosa.
abstract: Rehmannia glutinosa, one of the most widely used herbal medicines in the Orient, is rich in biologically active iridoids. Despite their medicinal importance, no molecular information about the iridoid biosynthesis in this plant is presently available. To explore the transcriptome of R. glutinosa and investigate genes involved in iridoid biosynthesis, we used massively parallel pyrosequencing on the 454 GS FLX Titanium platform to generate a substantial EST dataset. Based on sequence similarity searches against the public sequence databases, the sequences were first annotated and then subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) based analysis. Bioinformatic analysis indicated that the 454 assembly contained a set of genes putatively involved in iridoid biosynthesis. Significantly, homologues of the secoiridoid pathway genes that were only identified in terpenoid indole alkaloid producing plants were also identified, whose presence implied that route II iridoids and route I iridoids share common enzyme steps in the early stage of biosynthesis. The gene expression patterns of four prenyltransferase transcripts were analyzed using qRT-PCR, which shed light on their putative functions in tissues of R. glutinosa. The data explored in this study will provide valuable information for further studies concerning iridoid biosynthesis.
authors.affiliation: Institute of Medicinal Plant Development, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100193, China. xeli@implad.ac.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Sun
authors.forename: Shuhui
authors.initials: S
authors.lastname: Song
authors.forename: Lili
authors.initials: L
authors.lastname: Zhou
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.forename: Jianjun
authors.initials: J
authors.lastname: Qi
authors.forename: Xianen
authors.initials: X
authors.lastname: Li
mesh_terms: D016208:Databases, Factual; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015723:Gene Library; D039823:Iridoids / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000235:genetics / Q000378:metabolism; D032267:Rehmannia / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D039823:Iridoids