| Autor: |
Agarwal P; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India., Pathak S; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.; Department of Biochemistry, University of Lucknow, Lucknow, 226007, India., Kumar RS; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India., Dhar YV; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India., Pandey A; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India., Shukla S; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India., Trivedi PK; CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India. prabodht@nbri.res.in.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India. prabodht@nbri.res.in. |
| Abstrakt: |
Key Message: Using, in silico, in vitro and in planta functional assays, we demonstrate that Ps3'OMT, an 3'-O methyl transferase is linked to papaverine biosynthesis in opium poppy. Papaverine, one of the benzylisoquinoline alkaloids (BIA) synthesized in the medicinally important plant, Papaver somniferum, is known for the potent pharmacological properties. Papaverine biosynthesis has remained debatable as two different pathways, NH (involving N-desmethylated intermediates) and the NCH 3 (involving N-methylated intermediates), have been proposed. In addition, there are several intermediate steps in both the proposed pathways that are not very well characterized in terms of specific enzymes. In this study, we report the identification and functional characterization of 3'O-methyltransferase (Ps3'OMT) which might participate in the 3'O-methylation of the intermediates in the papaverine biosynthesis. Comparison of transcript and metabolite profiles of high and low papaverine producing cultivar revealed the occurrence of a 3'O-methyltransferase, Ps3'OMT, which was abundant in aerial organs and shared 72% identity with the GfLOMT7 predicted to have 3'OMT activity. In silico studies based on homology modeling, docking and MD simulations predicted (S)-norlaudanine as the potential substrate forming a stable complex with Ps3'OMT. Suppression of Ps3'OMT through virus-induced gene silencing resulted in a remarkable decrease in the level of papaverine in comparison to control plants. The characterization of the functionally unique Ps3'OMT involved in BIA metabolism suggests an involvement of the NH pathway leading to papaverine biosynthesis. |
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