title: Sulphur limitation and early sulphur deficiency responses in poplar: significance of gene expression, metabolites, and plant hormones.
abstract: The influence of sulphur (S) depletion on the expression of genes related to S metabolism, and on metabolite and plant hormone contents was analysed in young and mature leaves, fine roots, xylem sap, and phloem exudates of poplar (Populus tremula×Populus alba) with special focus on early consequences. S depletion was applied by a gradual decrease of sulphate availability. The observed changes were correlated with sulphate contents. Based on the decrease in sulphate contents, two phases of S depletion could be distinguished that were denominated as 'S limitation' and 'early S deficiency'. S limitation was characterized by improved sulphate uptake (enhanced root-specific sulphate transporter PtaSULTR1;2 expression) and reduction capacities (enhanced adenosine 5'-phosphosulphate (APS) reductase expression) and by enhanced remobilization of sulphate from the vacuole (enhanced putative vacuolar sulphate transporter PtaSULTR4;2 expression). During early S deficiency, whole plant distribution of S was impacted, as indicated by increasing expression of the phloem-localized sulphate transporter PtaSULTR1;1 and by decreasing glutathione contents in fine roots, young leaves, mature leaves, and phloem exudates. Furthermore, at 'early S deficiency', expression of microRNA395 (miR395), which targets transcripts of PtaATPS3/4 (ATP sulphurylase) for cleavage, increased. Changes in plant hormone contents were observed at 'early S deficiency' only. Thus, S depletion affects S and plant hormone metabolism of poplar during 'S limitation' and 'early S deficiency' in a time series of events. Despite these consequences, the impact of S depletion on growth of poplar plants appears to be less severe than in Brassicaceae such as Arabidopsis thaliana or Brassica sp.
authors.affiliation: Albert-Ludwigs-University Freiburg, Institute of Forest Botany and Tree Physiology, Freiburg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Honsel
authors.forename: Mikiko
authors.initials: M
authors.lastname: Kojima
authors.forename: Richard
authors.initials: R
authors.lastname: Haas
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Frank
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakakibara
authors.forename: Cornelia
authors.initials: C
authors.lastname: Herschbach
authors.forename: Heinz
authors.initials: H
authors.lastname: Rennenberg
mesh_terms: D000838:Anions / Q000378:metabolism; D001692:Biological Transport; D050260:Carbohydrate Metabolism; D002241:Carbohydrates; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D035683:MicroRNAs; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics; D052585:Phloem / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics*; D018517:Plant Roots / Q000378:metabolism; D032107:Populus / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D018749:RNA, Plant / Q000235:genetics; D013430:Sulfate Adenylyltransferase / Q000235:genetics; D013431:Sulfates / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013455:Sulfur / Q000172:deficiency* / Q000378:metabolism; D013997:Time Factors; D052584:Xylem / Q000378:metabolism
chemical_list: D000838:Anions; D002241:Carbohydrates; D035683:MicroRNAs; D010937:Plant Growth Regulators; D010940:Plant Proteins; D018749:RNA, Plant; D013431:Sulfates; D013438:Sulfhydryl Compounds; D013455:Sulfur; D050862:Oxidoreductases Acting on Sulfur Group Donors; C019618:adenylylsulfate reductase; D013430:Sulfate Adenylyltransferase