Engineering Tropane Alkaloid Production Based on Metabolic Characterization of Ornithine Decarboxylase in Atropa belladonna

• DOI: 10.1021/acssynbio.9b00461
• Publication Date: 2020-01-15T00:29:04Z
• Authors: Tengfei Zhao; Siqi Li; Jing Wang; Qi Zhou; Chunxian Yang; Feng Bai; Xiaozhong Lan; Min Chen; Zhihua Liao
• Keywords: Hyoscyamine; Atropa belladonna; Tropane; Arginine decarboxylase; Anisodamine; Metabolic Engineering

Ornithine decarboxylase (ODC) plays an important role in various biological processes; however, its plant secondary metabolism, especially the biosynthesis of tropane alkaloids (TAs) such as pharmaceutical hyoscyamine, anisodamine, and scopolamine, remains largely unknown. In this study, we characterized physiological metabolic functions ODC gene Atropa belladonna (AbODC) determined TA production using engineering approaches. Feeding assays with enzyme inhibitors indicated that ODC, rather than arginine (ADC), a major biosynthesis. Tissue-specific AbODC expression analysis β-glucuronidase (GUS) staining showed was highly expressed roots, cylinder tissue. Enzymatic able to convert ornithine putrescine, highest activity at pH 8.0 30 °C. Additionally, higher catalytic efficiency other ODCs, evident from Km, Vmax, Kcat values substrate. A. root cultures, suppression greatly reduced N-methylputrescine, TAs, whereas overexpression significantly increased anisodamine. Moreover, transgenic plants overexpressing hyoscyamine anisodamine compared control plants. These findings indicate key therefore is valuable candidate for increasing belladonna.