title: Sequestration, tissue distribution and developmental transmission of cyanogenic glucosides in a specialist insect herbivore.
abstract: Considering the staggering diversity of bioactive natural products present in plants, insects are only able to sequester a small number of phytochemicals from their food plants. The mechanisms of how only some phytochemicals are sequestered and how the sequestration process takes place remains largely unknown. In this study the model system of Zygaena filipendulae (Lepidoptera) and their food plant Lotus corniculatus is used to advance the knowledge of insect sequestration. Z. filipendulae larvae are dependent on sequestration of the cyanogenic glucosides linamarin and lotaustralin from their food plant, and have a much lower fitness if reared on plants without these compounds. This study investigates the fate of the cyanogenic glucosides during ingestion, sequestration in the larvae, and in the course of insect ontogeny. To this purpose, double-labeled linamarin and lotaustralin were chemically synthesized carrying two stable isotopes, a (2)H labeled aglucone and a (13)C labeled glucose moiety. In addition, a small amount of (14)C was incorporated into the glucose residue. The isotope-labeled compounds were applied onto cyanogenic L. corniculatus leaves that were subsequently presented to the Z. filipendulae larvae. Following ingestion by the larvae, the destiny of the isotope labeled cyanogenic glucosides was monitored in different tissues of larvae and adults at selected time points, using radio-TLC and LC-MS analyses. It was shown that sequestered compounds are taken up intact, contrary to earlier hypotheses where it was suggested that the compounds would have to be hydrolyzed before transport across the gut. The uptake from the larval gut was highly stereo selective as the β-glucosides were retained while the α-glucosides were excreted and recovered in the frass. Sequestered compounds were rapidly distributed into all analyzed tissues of the larval body, partly retained throughout metamorphosis and transferred into the adult insect where they were distributed to all tissues. During subsequent mating, isotope labeled cyanogenic glucosides were transferred from the male to the female in the nuptial gift.
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark. Electronic address: miz@life.ku.dk.
authors.forename: Mika
authors.initials: M
authors.lastname: Zagrobelny
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Carl Erik
authors.initials: CE
authors.lastname: Olsen
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pentzold
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Joel
authors.initials: J
authors.lastname: Fürstenberg-Hägg
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Jørgensen
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Bak
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Center for Biosustainability, Novo Nordisk Foundation, Technical University of Denmark, Denmark.
authors.forename: Birger Lindberg
authors.initials: BL
authors.lastname: Møller
authors.affiliation: Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Villum research center "Plant Plasticity" University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Mohammed Saddik
authors.initials: MS
authors.lastname: Motawia
mesh_terms: D000818:Animals; D001692:Biological Transport; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D060434:Herbivory / Q000502:physiology*; D007700:Kinetics; D007814:Larva / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism; D009036:Moths / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D009570:Nitriles / Q000737:chemistry / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D006027:Glycosides; D009570:Nitriles; C011206:cyanogen
keywords: Burnet moth; Cyanogenic glucosides; Plant–insect interactions; Sequestration; Zygaena filipendulae