title: Localization and expression of EDS5H a homologue of the SA transporter EDS5.
abstract: BACKGROUND
  An important signal transduction pathway in plant defence depends on the accumulation of salicylic acid (SA). SA is produced in chloroplasts and the multidrug and toxin extrusion transporter ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5; At4g39030) is necessary for the accumulation of SA after pathogen and abiotic stress. EDS5 is localized at the chloroplast and functions in transporting SA from the chloroplast to the cytoplasm. EDS5 has a homologue called EDS5H (EDS5 HOMOLOGUE; At2g21340) but its relationship to EDS5 has not been described and its function is not known.
  
  
  RESULTS
  EDS5H exhibits about 72% similarity and 59% identity to EDS5. In contrast to EDS5 that is induced after pathogen inoculation, EDS5H was constitutively expressed in all green tissues, independently of pathogen infection. Both transporters are located at the envelope of the chloroplast, the compartment of SA biosynthesis. EDS5H is not involved with the accumulation of SA after inoculation with a pathogen or exposure to UV stress. A phylogenetic analysis supports the hypothesis that EDS5H may be an H(+)/organic acid antiporter like EDS5.
  
  
  CONCLUSIONS
  The data based on genetic and molecular studies indicate that EDS5H despite its homology to EDS5 does not contribute to pathogen-induced SA accumulation like EDS5. EDS5H most likely transports related substances such as for example phenolic acids, but unlikely SA.
authors.affiliation: Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland. kpnongla@kmitl.ac.th.|Faculty of Agricultural Technology, King Mongkut's Institute of Technology Ladkrabang, Chalongkrung Rd., Ladkrabang, 10520, Bangkok, Thailand. kpnongla@kmitl.ac.th.
authors.forename: Nonglak
authors.initials: N
authors.lastname: Parinthawong
authors.affiliation: Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland. stephanie.cottier@unifr.ch.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Cottier
authors.affiliation: Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland. antony.buchala@unifr.ch.
authors.forename: Antony
authors.initials: A
authors.lastname: Buchala
authors.affiliation: Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland. christiane.nawrath@unil.ch.|Department of Plant Molecular Biology, University of Lausanne, 1015, Lausanne, Switzerland. christiane.nawrath@unil.ch.
authors.forename: Christiane
authors.initials: C
authors.lastname: Nawrath
authors.affiliation: Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland. jean-pierre.metraux@unifr.ch.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Métraux
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D015536:Down-Regulation / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D030821:Plants, Genetically Modified; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C455514:EDS5 protein, Arabidopsis; C000604311:EDS5H protein, Arabidopsis; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins; D005966:Glucuronidase; D020156:Salicylic Acid