Please cite this article in press as: Swigonska S, Weidner S. Proteomic analysis of response to long-term continuous stress in roots of germinating soybean seeds. J Plant Physiol (2013), http://dx.doi.org/10.1016/j.jplph.2012.11.020 ARTICLE IN PRESS G Model JPLPH-51655; No. of Pages 10 Journal of Plant Physiology xxx (2013) xxx–xxx Contents lists available at SciVerse ScienceDirect Journal of Plant Physiology j o ur nal homepage: www.elsevier.com/locate/jplph Physiology Proteomic analysis of response to long-term continuous stress in roots of germinating soybean seeds Sylwia Swigonska ∗ , Stanislaw Weidner Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego Street 1a, 10-957 Olsztyn, Poland a r t i c l e i n f o Article history: Received 29 June 2012 Received in revised form 12 October 2012 Accepted 16 November 2012 Keywords: Cold stress Germination Osmotic stress Proteomics Soybean a b s t r a c t Germination is a complex process, highly dependent on various environmental factors, including tem- perature and water availability. Germinating soybean seeds are especially vulnerable to unfavorable environmental conditions and exposure to long-term abiotic stresses may result in diminishing much of the yield and most importantly – restrained germination. In the present study, a proteomic approach was employed to analyze influence of cold and osmotic stress on roots of germinated soybean (Glycine max, L.) seeds. Seeds were germinating under continuous conditions of cold stress (+10 ◦ C/H 2 O), osmotic stress (+25 ◦ C/-0.2 MPa) as well as cold and osmotic stress combined (+10 ◦ C/-0.2 MPa). Proteome maps established for control samples and stress-treated samples displayed 1272 CBB-stained spots. A total of 59 proteins, present in both control and stress-treated samples and showing significant differences in volume, were identified with LC/nanoESI-MS. Identified proteins divided into functional categories, revealed 9 proteins involved in plant defense, 8 proteins responsible for plant destination and storage and 10 proteins involved in various tracks of carbohydrate metabolism. Furthermore, a number of pro- teins were assigned to electron transport, range of metabolic pathways, secondary metabolism, protein synthesis, embryogenesis and development, signal transduction, cellular transport, translocation and storage. By analyzing differences in expression patterns, it was possible to trace the soybean response to long-term abiotic stress as well as to distinguish similarities and differences between response to cold and osmotic stress. © 2013 Elsevier GmbH. All rights reserved. Introduction For many years the main focus of plant breeders has been to achieve cultivars resistant to pathogens and infections as well as producing stable yield, not dependent on day length and time of planting. Nowadays, many economically important crops are spread beyond their natural growth borders, experiencing condi- tions distinctly different from optimal ones (Funatsuki et al., 2003). Therefore, plant response and resistance to stress conditions is attracting growing attention. Plants’ exposure to environmental stresses, including low temperature and osmotic stress, induce changes in metabolism, leading to diminished productivity. The effect is especially evident in germination, which is a complex pro- cess, highly dependent on various factors, including temperature, water content and others. Germinating seeds are particularly vul- nerable to unfavorable environmental conditions, so exposure to ∗ Corresponding author at: Research and Education Center “Laboratory of Molec- ular Diagnostics”, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Prawochenskiego Street 5, 10-720 Olsztyn, Poland. Tel.: +48 89 524 52 83; fax: +48 89 524 52 86. E-mail address: sylwia.swigonska@uwm.edu.pl (S. Swigonska). severe stress may result in large loss of the yield and most impor- tantly – restrained germination. Studying stress-induced changes at the molecular level is essential not only for a better under- standing of processes underlying the stress response and plant acclimation, but most importantly for improving the quality of economically important crops, e.g. soybean. Many abiotic stresses, including cold, drought, salinity and others generate reactive oxy- gen species (ROS), which interact with cellular components like lipids, nucleic acids and proteins. Unfavorable changes, especially in plasma membranes, lead to a reduction of water potential in roots and difficulties in water acquisition. As a result, a negative osmotic pressure in roots arises, which causes osmotic stress. The occurrence of osmotic stress as secondary stress to exposure to low or high temperatures is obvious. Like most biological actions, low temperatures and osmotic stress involve the action and reg- ulation of multiprotein complexes and result in a wide range of morphological and physiological effects. The plant response to both stresses can be complex and may often lead to similar changes in gene expression, protein expression and metabolism (Thomashow, 1998; Renaut et al., 2006). There is certainly spe- cific cross-talk in signaling pathways during cold and osmotic stress, demonstrated in cell membrane modifications and acti- vation of common response pathways like MAPK cascades or 0176-1617/$ – see front matter © 2013 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.jplph.2012.11.020