title: Genes of primary sulfate assimilation are part of the glucosinolate biosynthetic network in Arabidopsis thaliana.
abstract: Glucosinolates are plant secondary metabolites involved in responses to biotic stress. The final step of their synthesis is the transfer of a sulfo group from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) onto a desulfo precursor. Thus, glucosinolate synthesis is linked to sulfate assimilation. The sulfate donor for this reaction is synthesized from sulfate in two steps catalyzed by ATP sulfurylase (ATPS) and adenosine 5'-phosphosulfate kinase (APK). Here we demonstrate that R2R3-MYB transcription factors, which are known to regulate both aliphatic and indolic glucosinolate biosynthesis in Arabidopsis thaliana, also control genes of primary sulfate metabolism. Using trans-activation assays we found that two isoforms of APK, APK1, and APK2, are regulated by both classes of glucosinolate MYB transcription factors; whereas two ATPS genes, ATPS1 and ATPS3, are differentially regulated by these two groups of MYB factors. In addition, we show that the adenosine 5'-phosphosulfate reductases APR1, APR2, and APR3, which participate in primary sulfate reduction, are also activated by the MYB factors. These observations were confirmed by analysis of transgenic lines with modulated expression levels of the glucosinolate MYB factors. The changes in transcript levels also affected enzyme activities, the thiol content and the sulfate reduction rate in some of the transgenic plants. Altogether the data revealed that the MYB transcription factors regulate genes of primary sulfate metabolism and that the genes involved in the synthesis of activated sulfate are part of the glucosinolate biosynthesis network.
authors.affiliation: Botanisches Institut der Universität zu Köln, Otto-Fischer-Str. 6, D-50674 Köln, Germany.
authors.forename: Ruslan
authors.initials: R
authors.lastname: Yatusevich
authors.forename: Sarah G
authors.initials: SG
authors.lastname: Mugford
authors.forename: Colette
authors.initials: C
authors.lastname: Matthewman
authors.forename: Tamara
authors.initials: T
authors.lastname: Gigolashvili
authors.forename: Henning
authors.initials: H
authors.lastname: Frerigmann
authors.forename: Sean
authors.initials: S
authors.lastname: Delaney
authors.forename: Anna
authors.initials: A
authors.lastname: Koprivova
authors.forename: Ulf-Ingo
authors.initials: UI
authors.lastname: Flügge
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kopriva
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005961:Glucosinolates / Q000096:biosynthesis*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D013430:Sulfate Adenylyltransferase / Q000235:genetics / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005961:Glucosinolates; D020598:Proto-Oncogene Proteins c-myb; D013431:Sulfates; D014157:Transcription Factors; D017853:Phosphotransferases (Alcohol Group Acceptor); C019617:adenylylsulfate kinase; D013430:Sulfate Adenylyltransferase