title: NRT/PTR transporters are essential for translocation of glucosinolate defence compounds to seeds.
abstract: In plants, transport processes are important for the reallocation of defence compounds to protect tissues of high value, as demonstrated in the plant model Arabidopsis, in which the major defence compounds, glucosinolates, are translocated to seeds on maturation. The molecular basis for long-distance transport of glucosinolates and other defence compounds, however, remains unknown. Here we identify and characterize two members of the nitrate/peptide transporter family, GTR1 and GTR2, as high-affinity, proton-dependent glucosinolate-specific transporters. The gtr1 gtr2 double mutant did not accumulate glucosinolates in seeds and had more than tenfold over-accumulation in source tissues such as leaves and silique walls, indicating that both plasma membrane-localized transporters are essential for long-distance transport of glucosinolates. We propose that GTR1 and GTR2 control the loading of glucosinolates from the apoplasm into the phloem. Identification of the glucosinolate transporters has agricultural potential as a means to control allocation of defence compounds in a tissue-specific manner.
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871Frederiksberg C, Denmark.
authors.forename: Hussam Hassan
authors.initials: HH
authors.lastname: Nour-Eldin
authors.forename: Tonni Grube
authors.initials: TG
authors.lastname: Andersen
authors.forename: Meike
authors.initials: M
authors.lastname: Burow
authors.forename: Svend Roesen
authors.initials: SR
authors.lastname: Madsen
authors.forename: Morten Egevang
authors.initials: ME
authors.lastname: Jørgensen
authors.forename: Carl Erik
authors.initials: CE
authors.lastname: Olsen
authors.forename: Ingo
authors.initials: I
authors.lastname: Dreyer
authors.forename: Rainer
authors.initials: R
authors.lastname: Hedrich
authors.forename: Dietmar
authors.initials: D
authors.lastname: Geiger
authors.forename: Barbara Ann
authors.initials: BA
authors.lastname: Halkier
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002457:Cell Extracts / Q000737:chemistry; D019143:Evolution, Molecular; D017353:Gene Deletion; D015723:Gene Library; D017343:Genes, Plant / Q000235:genetics; D005961:Glucosinolates / Q000378:metabolism* / Q000494:pharmacology; D009004:Monosaccharide Transport Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D009928:Organ Specificity; D052585:Phloem / Q000378:metabolism; D011522:Protons; D012639:Seeds / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D029681:Arabidopsis Proteins; D002457:Cell Extracts; C575185:GTR1 protein, Arabidopsis; C575186:GTR2 protein, Arabidopsis; D005961:Glucosinolates; D009004:Monosaccharide Transport Proteins; D011522:Protons