Characterization of a vacuolar importer of secologanin in Catharanthus roseus

• Published in: Communications biology 2024-08, Vol.7 (1), p.939-10, Article 939
• Main Authors: Li, Fanfan, Shahsavarani, Mohammadamin, Handy-Hart, Cody-Jordan, Côté, Audrey, Brasseur-Trottier, Xavier, Montgomery, Victoria, Beech, Robin N., Liu, Lan, Bayen, Stéphane, Qu, Yang, De Luca, Vincenzo, Dastmalchi, Mehran
• Format: Article
• Language: English
• Subjects: 101/58; 14/19; 38/39; 38/77; 42/41; 45/90; 631/449/2667; 631/449/448/2651; Alkaloids; Animals; Antineoplastic drugs; Biological Transport; Biomedical and Life Sciences; Biosynthesis; Catharanthus - genetics; Catharanthus - metabolism; Catharanthus roseus; Cell differentiation; Homeostasis; Iridoid Glucosides; Life Sciences; Localization; Metabolism; Oocytes - metabolism; Organelles; Phylogeny; Plant Proteins - genetics; Plant Proteins - metabolism; Secologanin Tryptamine Alkaloids - metabolism; Vacuoles - metabolism; Vinblastine; Xenopus laevis - metabolism
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-024-06624-5

Monoterpenoid indole alkaloid (MIA) biosynthesis in Catharanthus roseus is a paragon of the spatiotemporal complexity achievable by plant specialized metabolism. Spanning a range of tissues, four cell types, and five cellular organelles, MIA metabolism is intricately regulated and organized. This high degree of metabolic differentiation requires inter-cellular and organellar transport, which remains understudied. Here, we have characterized a vacuolar importer of secologanin belonging to the multidrug and toxic compound extrusion (MATE) family, named CrMATE1. Phylogenetic analyses of MATEs suggested a role in alkaloid transport for CrMATE1, and in planta silencing in two varieties of C. roseus resulted in a shift in the secoiridoid and MIA profiles. Subcellular localization of CrMATE1 confirmed tonoplast localization. Biochemical characterization was conducted using the Xenopus laevis oocyte expression system to determine substrate range, directionality, and rate. We can confirm that CrMATE1 is a vacuolar importer of secologanin, translocating 1 mM of substrate within 25 min. The transporter displayed strict directionality and specificity for secologanin and did not accept other secoiridoid substrates. The unique substrate-specific activity of CrMATE1 showcases the utility of transporters as gatekeepers of pathway flux, mediating the balance between a defense arsenal and cellular homeostasis. Characterization of CrMATE1 as a vacuolar importer of secologanin in Catharanthus roseus ; the transport of secologanin is required for the first committed step of monoterpenoid indole alkaloid biosynthesis, ultimately leading to the anticancer drug vinblastine.