The biosynthesis of brassicicolin A in the phytopathogen Alternaria brassicicola.
Alternaria brassicicola (Schwein.) Wiltshire is a phytopathogenic fungus that together with A. brassicae causes Alternaria black spot disease in Brassica species. Brassicicolin A is the major host-selective phytotoxin produced in cultures of A. brassicicola. Biosynthetic studies to establish the metabolic precursors of brassicicolin A were carried out with isotopically labeled compounds. Incorporation of D-[13C6]glucose, L-[15N]valine, or L-[2H8]valine into brassicicolin A was established using1H,13C,15N NMR and INADEQUATE spectroscopy and HPLC-ESI-MS spectrometry. Based on analyses of the spectroscopic data, the labeling patterns of brassicicolin A isolated from cultures incubated with the labeled precursors are found to be consistent with both the glycolytic and the valine pathways. That is, the carbons of mannitol and acetyl units and the isocyanide carbon atoms are derived from D-[13C6]glucose whereas the hydroxyisopentanoyl and isocyanoisopentanoyl units are derived from L-valine, including the nitrogen atoms of both isocyanide groups.
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, S7N 5C9, Canada. Electronic address: s.pedras@usask.ca.
M Soledade C
MSC
Pedras
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, S7N 5C9, Canada.
Myung Ryeol
MR
Park
D000528:Alternaria / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism; D006016:Glycolates / Q000378:metabolism; D009149:Mustard Plant / Q000382:microbiology*; D009570:Nitriles / Q000737:chemistry / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D031226:Sinapis; D014633:Valine / Q000378:metabolism
D006016:Glycolates; D009570:Nitriles; C000614423:brassicicolin A; C031149:glycolic acid; D014633:Valine; D005947:Glucose
Alternaria brassicicola; B. rapa; Biosynthesis; Brassica juncea; Brassicicolin A; Crucifer; Host-selective phytotoxin; Sinapis alba