Authors: Sara Thodberg, Mette Sørensen, Matteo Bellucci, Christoph Crocoll, Amalie Kofoed Bendtsen, David Ralph Nelson, Mohammed Saddik Motawia, Birger Lindberg Møller & Elizabeth Heather Jakobsen Neilson

Institutions:

  • Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Copenhagen, Denmark
  • VILLUM Center for Plant Plasticity, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Copenhagen, Denmark
  • Novo Nordisk Foundation Center for Protein Research, Protein Production and Characterization Platform, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark
  • Section for Plant Molecular Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Copenhagen, Denmark
  • Department of Microbiology, Immunology and Biochemistry, University of Tennessee, 858 Madison Ave. Suite G01, Memphis, TN, 38163, USA

Publication: Communications Biology

Date: September 2021

Full paper: https://www.nature.com/articles/s42003-020-01224-5

Abstract:

Cyanogenic glycosides form part of a binary plant defense system that, upon catabolism, detonates a toxic hydrogen cyanide bomb. In seed plants, the initial step of cyanogenic glycoside biosynthesis—the conversion of an amino acid to the corresponding aldoxime—is catalyzed by a cytochrome P450 from the CYP79 family. An evolutionary conundrum arises, as no CYP79s have been identified in ferns, despite cyanogenic glycoside occurrence in several fern species. Here, we report that a flavin-dependent monooxygenase (fern oxime synthase; FOS1), catalyzes the first step of cyanogenic glycoside biosynthesis in two fern species (Phlebodium aureum and Pteridium aquilinum), demonstrating convergent evolution of biosynthesis across the plant kingdom. The FOS1 sequence from the two species is near identical (98%), despite diversifying 140 MYA. Recombinant FOS1 was isolated as a catalytic active dimer, and in planta, catalyzes formation of an N-hydroxylated primary amino acid; a class of metabolite not previously observed in plants.