Sulphur limitation and early sulphur deficiency responses in poplar: significance of gene expression, metabolites, and plant hormones

• Published in: Journal of experimental botany 2012-03, Vol.63 (5), p.1873-1893
• Main Authors: Honsel, Anne, Kojima, Mikiko, Haas, Richard, Frank, Wolfgang, Sakakibara, Hitoshi, Herschbach, Cornelia, Rennenberg, Heinz
• Format: Article
• Language: English
• Subjects: Anions - metabolism; Arabidopsis thaliana; Biological and medical sciences; Biological Transport; Brassica; Brassicaceae; Carbohydrate Metabolism; Carbohydrates; Cytokinins; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Gene Expression Regulation, Plant - genetics; Leaves; MicroRNAs; Oxidoreductases Acting on Sulfur Group Donors - genetics; Phloem; Phloem - metabolism; Plant growth regulators; Plant Growth Regulators - metabolism; Plant Leaves - metabolism; Plant physiology and development; Plant Proteins - genetics; Plant roots; Plant Roots - metabolism; Plants; Populus; Populus - enzymology; Populus - genetics; Populus - physiology; RESEARCH PAPER; Research Papers; RNA; RNA, Plant - genetics; Sulfate Adenylyltransferase - genetics; Sulfates - metabolism; Sulfhydryl Compounds - metabolism; Sulfur; Sulfur - deficiency; Sulfur - metabolism; Time Factors; Xylem; Xylem - metabolism
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/err365

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;2expression) 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;2expression). During early S deficiency, whole plant distribution of S was impacted, as indicated by increasing expression of the phloem-localized sulphate transporter PtaSULTR1;1and 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 asArabidopsis thalianaorBrassicasp.