Expanding the Phytoalexin Chemical Space: Tropalexins a and B from Tropaeolum Majus Suggest Evolutionary Conservation of Biosynthetic Enzymes

Abstract

Tropalexins A and B, the first phytoalexins isolated from Tropaeolum majus (Brassicales order, Tropaeolaceae family), together with their antifungal activity and biosynthetic precursors are disclosed. These plant defenses contain a 1,3-benzothiazine ring and are shown to derive from Phe via the glucosinolate glucotropaeolin, which indicates that T. majus employs a phytoalexin biosynthetic pathway closely related to the pathway operating in Brassica spp. (Brassicales order, Brassicaceae family) and suggests an evolutionary conservation of key biosynthetic enzymes

Phytoalexins and Signalling Metabolites Produced in the Wild Crucifer Neslia Paniculata: Camalexins and Arabidopsides

“…Curiously, due to the research impact of the model plant A. thaliana, camalexin ( 9) benefits from the highest popularity among the ca. 60 cruciferous phytoalexins reported to date (Pedras and Abdoli, 2017;Pedras et al, 2019;Pedras and Alavi, 2020). This popularity is reflected in the number of publications, with more than 440 articles retrieved through the SciFinder database (accessed March 2021 using the keyword "camalexin").…”

“…The similarity among the chemical transformations occurring in phytoalexin pathways of Brassicales species suggests an evolutionary conservation of biosynthetic enzymes (Pedras and Alavi, 2020). Furthermore, a striking correlation among the chemical structures of phytoalexins within selected groups of plant species led us to suggest that species in phylogenetically related tribes produce structurally similar and/or identical phytoalexins (Pedras and Alavi, 2020). For example, (i) brassinins 1 and 2 are produced in various species of the tribe Brassiceae, (ii) wasalexins A (3) and B (4) are produced in species of the closely related tribes Thlaspideae (Thlaspi arvense L.) and Eutremeae (Thellungiella salsuginea (Pall.)…”

Phytoalexins and Signalling Metabolites Produced in the Wild Crucifer Neslia Paniculata: Camalexins and Arabidopsides

“…Brassicales species, and in particular Brassicaceae species, produce unique arrays of phytoalexins with S,N-containing structures that are mostly derived from either (S)-Trp, via 3methylindolyl GL (7) and methoxy derivatives, or (S)-Phe via benzyl GL (8) and hydroxy/methoxy derivatives (Pedras et al, 2011;Pedras andTo, 2015, 2016). The similarity among the chemical transformations occurring in phytoalexin pathways of Brassicales species suggests an evolutionary conservation of biosynthetic enzymes (Pedras and Alavi, 2020). Furthermore, a striking correlation among the chemical structures of phytoalexins within selected groups of plant species led us to suggest that species in phylogenetically related tribes produce structurally similar and/or identical phytoalexins (Pedras and Alavi, 2020).…”