The Phytoalexins from Brassicaceae: Structure, Biological Activity, Synthesis and Biosynthesis

Abstract

The structures, biological activity, synthesis and biosynthesis of crucifer phytoalexins are reviewed.

Indole glucosinolate breakdown and its biological effects

“…Assuming that indole phytoalexins in B. juncea are synthesized by a similar pathway, IAN production would be induced by L. maculans infection. In contrast to previous suggestions inspired by structural similarity, other indole phytoalexins are also biosynthesized independently of indole glucosinolates, from the shared precursor indol-3-ylacetaldoxime (Pedras et al 2002;Glawischnig et al 2004;Pedras et al 2007) and from indol-3-ylacetothiohydroxamic acid (Pedras and Okinyo 2008).…”

Phytoalexins and phytoanticipins from the wild crucifers Thellungiella halophila and Arabidopsis thaliana: Rapalexin A, wasalexins and camalexin

“…As well, in the polar fraction of the aerial parts of A. thaliana, tryptophan could be identified in larger amounts than in control plants (Table 2). This is not surprising since tryptophan is a precursor of many of the indolyl metabolites reported above (Pedras et al, 2007b).…”

“…While phytoalexins are defense metabolites biosynthesized de novo, phytoanticipins are constitutive but their production can increase in response to various forms of stress (VanEtten et al, 1994). Plants are known to accumulate complex phytoalexin blends in response to stress, although the only phytoalexin reported from A. thaliana is camalexin (9) (Tsuji et al, 1992) and no phytoalexins from T. halophila are known (Pedras et al, 2007b). Considering the relevance of the species A. thaliana and T. halophila as model systems, we undertook to determine the phytoalexins and phytoanticipins produced by both crucifer species under abiotic stress conditions.…”

Cloning, purification and characterisation of brassinin glucosyltransferase, a phytoalexin-detoxifying enzyme from the plant pathogen Sclerotinia sclerotiorum

“…Most of these phytoalexins are derived from tryptophan and a few such as brassinin contain a dithiocarbamate group (for review see Pedras, 2008). A variety of phytoalexins are produced by Brassica species in response to infection by ascomycetes such as Leptosphaeria maculans, which causes blackleg or phoma stem canker, Sclerotinia sclerotorium, which causes stem rot of crucifers and the oomycete Albugo candida, which causes white rust of many cruciferous species (Pedras et al, 2007c). Camalexin is a determinant of resistance of Arabidopsis thaliana to the necrotrophic fungus, Botrytis cinerea (teleomorph Botryotinia fuckeliana); mutants (PAD2 and PAD3) deficient in camalexin production develop larger lesions than wild type plants upon infection (Ferrari et al, 2003).…”