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Transcriptome Profiling of Alkaloid Biosynthesis in Elicitor Induced Opium Poppy

2015    Gurkok, Tugba; Turktas, Mine; Parmaksiz, Iskender; Unver, Turgay

Alkaloids are derived mainly from amino acids, and their biosynthesis includes multistep reactions. Benzylisoquinoline alkaloids (BIA), which are secondary metabolites, are produced by the medically and economically important opium poppy (Papaver somniferum L.). The latex of poppy capsule is the main source of BIA, including mainly opium alkaloids such as codeine, papaverine, thebaine, and noscapine. To analyze BIA-related gene expression at the molecular level, genome-wide transcriptome analyses were carried out in opium-poppy capsule tissues, using 12 x 135 K (12 x 135,000 features) NimbleGen microarrays of opium poppy at 0, 3, and 12 h. Fungal elicitor methyl jasmonate (MeJa) treatment was applied to the surface of the capsules of opium poppy at 0, 3, and 12 h. The measurement of specific BIA showed that the treated capsules were especially rich in morphine and noscapine. The differential expression of genes related to BIA biosynthesis was detected from 3 to 12 h after MeJa treatment. Overall, 2,459 out of the 95,608 probes identified specific differential gene expression. Many altered transcripts (629) were detected after 12 h of treatment. Altered levels of gene expression were also detected in BIA biosynthesis-pathway genes, such as NCS, CNMT, SalR, 16TOMT, 6OMT, COR and StySyn. Gene ontology analyses revealed that the differentially expressed genes were involved in many processes and functions. Upon induction with MeJa, response to stimuli- and stress-related transcripts were induced significantly in opium poppies. In addition, transcripts related to specific metabolic processes were well represented. Pathway analysis revealed that BIA biosynthesis, cysteine and methionine metabolism, sucrose and starch metabolism, as well as purine metabolism pathways were affected significantly. This study provides insights into the molecular mechanism of opium-poppy defense upon MeJa treatment, facilitating a better understanding of processes underlying the BIA biosynthesis network.