The saponin bomb a nucleolar-localized β-glucosidase hydrolyzes triterpene saponins in Medicago truncatula

The saponin bomb : a nucleolar-localized β-glucosidase hydrolyzes triterpene saponins in Medicago truncatula

© 2023 The Authors New Phytologist © 2023 New Phytologist Foundation.

Bibliographische Detailangaben
Veröffentlicht in:The New phytologist. - 1979. - 239(2023), 2 vom: 14. Juli, Seite 705-719
1. Verfasser: Lacchini, Elia (VerfasserIn)
Weitere Verfasser: Erffelinck, Marie-Laure, Mertens, Jan, Marcou, Shirley, Molina-Hidalgo, Francisco Javier, Tzfadia, Oren, Venegas-Molina, Jhon, Cárdenas, Pablo D, Pollier, Jacob, Tava, Aldo, Bak, Søren, Höfte, Monica, Goossens, Alain
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2023
Zugriff auf das übergeordnete Werk:The New phytologist
Schlagworte:Journal Article Research Support, Non-U.S. Gov't Medicago truncatula bioactive triterpenes jasmonate liquid-liquid phase plant defense saponins specialized metabolism β-glucosidase mehr... Triterpenes Saponins beta-Glucosidase EC 3.2.1.21
Beschreibung
Zusammenfassung:© 2023 The Authors New Phytologist © 2023 New Phytologist Foundation.
Plants often protect themselves from their own bioactive defense metabolites by storing them in less active forms. Consequently, plants also need systems allowing correct spatiotemporal reactivation of such metabolites, for instance under pathogen or herbivore attack. Via co-expression analysis with public transcriptomes, we determined that the model legume Medicago truncatula has evolved a two-component system composed of a β-glucosidase, denominated G1, and triterpene saponins, which are physically separated from each other in intact cells. G1 expression is root-specific, stress-inducible, and coregulated with that of the genes encoding the triterpene saponin biosynthetic enzymes. However, the G1 protein is stored in the nucleolus and is released and united with its typically vacuolar-stored substrates only upon tissue damage, partly mediated by the surfactant action of the saponins themselves. Subsequently, enzymatic removal of carbohydrate groups from the saponins creates a pool of metabolites with an increased broad-spectrum antimicrobial activity. The evolution of this defense system benefited from both the intrinsic condensation abilities of the enzyme and the bioactivity properties of its substrates. We dub this two-component system the saponin bomb, in analogy with the mustard oil and cyanide bombs, commonly used to describe the renowned β-glucosidase-dependent defense systems for glucosinolates and cyanogenic glucosides
Beschreibung:Date Completed 15.06.2023
Date Revised 21.06.2023
published: Print-Electronic
Citation Status MEDLINE
ISSN:1469-8137
DOI:10.1111/nph.18763