Mai, Zhan2025-05-222025-05-222025-03https://unbscholar.lib.unb.ca/handle/1882/38305Cytochrome P450 monooxygenases (CYPs) play a crucial role in monoterpenoid indole alkaloid (MIA) biosynthesis, mediating oxidation reactions like hydroxylation, epoxidation, and ring modifications that drive structural diversity. Despite advances in MIA pharmaceutical biosynthesis, many tailoring reactions remain poorly understood. By integrating transcriptomic and metabolomic data from Tabernaemontana litoralis and Vinca minor, I identified a novel MIA, 11-hydroxypseudovincadifformine, and characterized five CYPs involved in MIA oxidation. TliTbE from T. litoralis catalyzes pachysiphine formation, a lochnericine stereoisomer. TliPs18H is the first CYP modifying a pseudoaspidosperma skeleton. TliC10H hydroxylates voaphylline, while VmPs10H in V. minor completes akuammine biosynthesis and hydroxylates related MIAs. VmV10H further oxidizes structurally diverse MIAs. This study expands our understanding of MIA biosynthesis and enzyme function, unlocking new biocatalysts for MIA production and demonstrating the untapped potential of these plants in alkaloid diversification.xi, 208electronicenhttp://purl.org/coar/access_right/c_abf2master thesisQu, YangChemistry