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Background The Himalayan or Indian Mayapple (Podophyllum hexandrum Royle) produces podophyllotoxin, which is used in the production of semisynthetic anticancer drugs. High throughput transcriptome sequences or genomic sequence data from the Indian Mayapple are essential for further understanding of the podophyllotoxin biosynthetic pathway. Results 454 pyrosequencing of a P. hexandrum cell culture normalized cDNA library generated 2,667,207 raw reads and 1,503,232 high quality reads, with an average read length of 138 bp. The denovo assembly was performed by Newbler using default and optimized parameters. The optimized parameter generated 40, 380 assembled sequences, comprising 12,940 contigs and 27,440 singlets which resulted in better assembly as compared to default parameters. BLASTX analysis resulted in the annotation of 40,380 contigs/singlet using a cut-off value of ⩽1E-03. High similarity to Medicago truncatula using optimized parameters and to Populus trichocarpa using default parameters was noted. The Kyoto encyclopedia of genes and genomes (KEGG) analysis using KEGG Automatic Annotation Server (KAAS) combined with domain analysis of the assembled transcripts revealed putative members of secondary metabolism pathways that may be involved in podophyllotoxin biosynthesis. A proposed schematic pathway for phenylpropanoids and podophyllotoxin biosynthesis was generated. Expression profiling was carried out based on fragments per kilobase of exon per million fragments (FPKM). 1036 simple sequence repeats were predicted in the P. hexandrum sequences. Sixty-nine transcripts were mapped to 99 mature and precursor microRNAs from the plant microRNA database. Around 961 transcripts containing transcription factor domains were noted. High performance liquid chromatography analysis showed the peak accumulation of podophyllotoxin in 12-day cell suspension cultures. A comparative qRTPCR analysis of phenylpropanoid pathway genes identified in the present data was performed to analyze their expression patterns in 12-day cell culture, callus and rhizome. Conclusions The present data will help the identification of the potential genes and transcription factors involved in podophyllotoxin biosynthesis in P. hexandrum. The assembled transcripts could serve as potential candidates for marker discovery and conservation, which should form the foundations for future endeavors. [ABSTRACT FROM AUTHOR]

Background: Podophyllotoxin (PTOX), the precursor for semi-synthesis of cancer therapeutics like etoposide, teniposide and etophos, is primarily obtained from an endangered medicinal herb, Podophyllum hexandrum Royle. PTOX, a lignan is biosynthetically derived from the phenylpropanoid pathway. The aim of this study is to investigate changes in the P. hexandrum cell proteome potentially related to PTOX accumulation in response to methyl jasmonate (MeJA) elicitation. High-resolution two-dimensional gel electrophoresis (2-DE) followed by colloidal Coomassie staining and mass spectrometric analysis was used to detect statistically significant changes in cell's proteome. Result: The HPLC analysis showed approximately 7-8 fold change in accumulation of PTOX, in the 12day old cell suspension culture (i.e. after 9days of elicitation) elicited with 100 µM MeJA as compared to the control. Using 2-DE a total of 233 spots was detected, out of which 105 spots were identified by MALDI TOF-TOF MS/MS. Data were subjected to functional annotation from a biological point of view through KEGG. The phenylpropanoid and monolignol pathway enzymes were identified, amongst these, chalcone synthase, polyphenol oxidase, caffeoyl CoA 3-O-methyltransferase, S-adenosyl-L-methionine-dependent methyltransferases, caffeic acid-O-methyl transferase etc. are noted as important. The relation of other differentially accumulated proteins with varied effects caused by elicitors on P. hexandrum cells namely stress and defense related protein, transcription and DNA replication and signaling are also discussed. Conclusions: Elicitor-induced PTOX accumulation in P. hexandrum cell cultures provides a responsive model system to profile modulations in proteins related to phenylpropanoid/monolignol biosynthesis and other defense responses. Present findings form a baseline for future investigation on a non-sequenced medicinal herb P. hexandrum at molecular level. [ABSTRACT FROM AUTHOR]