title: Functional identification of genes responsible for the biosynthesis of 1-methoxy-indol-3-ylmethyl-glucosinolate in Brassica rapa ssp. chinensis.
abstract: BACKGROUND
  Brassica vegetables contain a class of secondary metabolites, the glucosinolates (GS), whose specific degradation products determine the characteristic flavor and smell. While some of the respective degradation products of particular GS are recognized as health promoting substances for humans, recent studies also show evidence that namely the 1-methoxy-indol-3-ylmethyl GS might be deleterious by forming characteristic DNA adducts. Therefore, a deeper knowledge of aspects involved in the biosynthesis of indole GS is crucial to design vegetables with an improved secondary metabolite profile.
  
  
  RESULTS
  Initially the leafy Brassica vegetable pak choi (Brassica rapa ssp. chinensis) was established as suitable tool to elicit very high concentrations of 1-methoxy-indol-3-ylmethyl GS by application of methyl jasmonate. Differentially expressed candidate genes were discovered in a comparative microarray analysis using the 2 × 104 K format Brassica Array and compared to available gene expression data from the Arabidopsis AtGenExpress effort. Arabidopsis knock out mutants of the respective candidate gene homologs were subjected to a comprehensive examination of their GS profiles and confirmed the exclusive involvement of polypeptide 4 of the cytochrome P450 monooxygenase subfamily CYP81F in 1-methoxy-indol-3-ylmethyl GS biosynthesis. Functional characterization of the two identified isoforms coding for CYP81F4 in the Brassica rapa genome was performed using expression analysis and heterologous complementation of the respective Arabidopsis mutant.
  
  
  CONCLUSIONS
  Specific differences discovered in a comparative microarray and glucosinolate profiling analysis enables the functional attribution of Brassica rapa ssp. chinensis genes coding for polypeptide 4 of the cytochrome P450 monooxygenase subfamily CYP81F to their metabolic role in indole glucosinolate biosynthesis. These new identified Brassica genes will enable the development of genetic tools for breeding vegetables with improved GS composition in the near future.
authors.forename: Melanie
authors.initials: M
authors.lastname: Wiesner
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
authors.affiliation: Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren and Erfurt e,V,, Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany. zrenner@igzev.de.
authors.forename: Rita
authors.initials: R
authors.lastname: Zrenner
mesh_terms: D000085:Acetates / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000187:drug effects / Q000235:genetics; D029741:Brassica rapa / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D003517:Cyclopentanes / Q000494:pharmacology; D060146:Ecotype; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D055786:Gene Knockout Techniques; D017343:Genes, Plant; D056726:Genetic Association Studies; D018525:Germination / Q000187:drug effects; D005961:Glucosinolates / Q000096:biosynthesis*; D007211:Indoles; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D014170:Transformation, Genetic / Q000187:drug effects
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D005961:Glucosinolates; D007211:Indoles; D054883:Oxylipins; D010940:Plant Proteins; D020033:Protein Isoforms; C064701:1-methoxy-3-indolylmethylglucosinolate; C072239:methyl jasmonate