Research article Sulfate resupply accentuates protein synthesis in coordination with nitrogen metabolism in sulfur deprived Brassica napus Qian Zhang a , Bok-Rye Lee a, b , Sang-Hyun Park a , Rashed Zaman a , Jean-Christophe Avice c, d , Alain Ourry c, d , Tae-Hwan Kim a, * a Department of Animal Science, Institute of Agricultural Science and Technology, College of Agriculture & Life Science, Chonnam National University, Buk- Gwangju P.O Box 205, Gwangju 500-600, Republic of Korea b Biotechnology Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea c Universit e de Caen Basse-Normandie, Esplanade de la Paix, F-14032 Caen Cedex, France d UCBN, UMR INRA-UCBN 950 Ecophysiologie V eg etale, Agronomie et Nutritions N, C, S, Esplanade de la Paix, 14032 Caen Cedex, France article info Article history: Received 14 October 2014 Accepted 10 December 2014 Available online 11 December 2014 Keywords: Brassica napus Interaction N and S 15 N and 34 S chase S deprivation Sulfate assimilation abstract To investigate the regulatory interactions between S assimilation and N metabolism in Brassica napus, de novo synthesis of amino acids and proteins was quantified by 15 N and 34 S tracing, and the responses of transporter genes, assimilatory enzymes and metabolites pool involving in nitrate and sulfate meta- bolism were assessed under continuous sulfur supply, sulfur deprivation and sulfate resupply after 3 days of sulfur (S) deprivation. S-deprived plants were characterized by a strong induction of sulfate trans- porter genes, ATP sulfurylase (ATPS) and adenosine 5 0 -phosphosulfate reductase (APR), and by a repressed activity of nitrate reductase (NR) and glutamine synthetase (GS). Sulfate resupply to the S- deprived plants strongly increased cysteine, amino acids and proteins concentration. The increase in sulfate and cysteine concentration caused by sulfate resupply was not matched with the expression of sulfate transporters and the activity of ATPS and APR which were rapidly decreased by sulfate resupply. A strong induction of O-acetylserine(thiol)lyase (OASTL), NR and GS upon sulfate resupply was accompa- nied with the increase in cysteine, amino acids and proteins pool. Sulfate resupply resulted in a strong increase in de novo synthesis of amino acids and proteins, as evidenced by the increases in N and S incorporation into amino acids (1.8- and 2.4-fold increase) and proteins (2.2-and 6.3-fold increase) when compared to S-deprived plants. The results thus indicate that sulfate resupply followed by S-deprivation accelerates nitrate assimilation for protein synthesis. © 2014 Elsevier Masson SAS. All rights reserved. 1. Introduction Oilseed rape (Brassica napus L.) has a higher critical N and S demand (Berry et al., 2010) and requires relatively high amount of other nutrients (Rathke et al., 2006) when compared to cereals. In recent decades, the reduction of industrial S emissions to the at- mosphere and the subsequent reduction of deposition on the soil have increased the incidence of S-limitation in oilseed rape in many agricultural areas (McGrath and Zhao, 1995). The limitation of sulfur supply generally induces multiple responses facilitating sulfate uptake efficiency at the whole plant level. For instance, in sulfate deprived plants, there is strongly enhanced expression of various members of the sulfate transporters (Hawkesford, 2003; Buchner et al., 2004; Kataoka et al., 2004; Koralewska et al., 2009). The uptake, distribution and reduction of sulfate in plants are driven presumably by the sulfur demand for growth (Anderson and Fitzgerald, 2003) and highly coordinated with exogenous sulfur supply (Hawkesford, 2003; Buchner et al., 2004). However, there was apparently no strict and direct shoot to root signaling for the regulation of sulfate uptake and transport to the shoot in relation to the variation in sulfur supply (Hawkesford and De Kok, 2006). The relationship between sulfate content and expression of the sulfate transporters is ambiguous (Koralewska et al., 2009). For example, the increase in the overall capacity of sulfate uptake by root is limited (Hawkesford, 2003; Buchner et al., 2004; Lee et al., 2013, 2014), although the expression of sulfate transporters is strongly enhanced under S-limitation (Buchner et al., 2004; Kataoka et al., 2004; Honsel et al., 2012). * Corresponding author. E-mail address: grassl@chonnam.ac.kr (T.-H. Kim). Contents lists available at ScienceDirect Plant Physiology and Biochemistry journal homepage: www.elsevier.com/locate/plaphy http://dx.doi.org/10.1016/j.plaphy.2014.12.006 0981-9428/© 2014 Elsevier Masson SAS. All rights reserved. Plant Physiology and Biochemistry 87 (2015) 1e8