SHORT COMMUNICATION Differential expression of heat-shock proteins Hsp70 and Hsp90 in vegetative and reproductive tissues of Iris pumila Sanja Manitas ˇevic ´ Jovanovic ´ • Branka Tucic ´ • Gordana Matic ´ Received: 18 December 2009 / Revised: 11 March 2010 / Accepted: 17 May 2010 Ó Franciszek Go ´rski Institute of Plant Physiology, Polish Academy of Sciences, Krako ´w 2010 Abstract Tissue-specific variation in Hsp70 and Hsp90 expression was studied in vegetative (leaf) and reproduc- tive organs (floral tube, ovary and stamen) of Iris pumila plants originating from a sun-exposed and a shaded natural population, which experienced similar growth conditions in an experimental garden. Western blot analysis revealed the presence of both the Hsps in all examined tissues, but at different amounts. In addition to Hsp90a and Hsp90b that were previously detected in vegetative tissues, three new immunospecific bands, designated herein as Hsp90c, Hsp90d and Hsp90e, were recognized with the same anti- Hsp90 antibody in the reproductive tissues. Apart from showing tissue-specific differences in the relative amount of Hsp70 and Hsp90, our study provides evidence that the degree of Hsps expression within the same tissue also depended on the habitat type that the I. pumila plants were derived from. Keywords Hsp70 Á Hsp90 Á Hsp90 isoforms Á Iris pumila L. Á Tissue-specific expression Abbreviations BSA Bovine serum albumin DTT Dithiothreitol EDTA Ethylenediaminetetraacetic acid PBS Phosphate-buffered saline SDS-PAGE Sodium dodecyl sulfate-polyacrylamide gel electrophoresis PMSF Phenylmethylsulfonylfluoride Introduction Heat-shock proteins comprise an evolutionary highly con- served group of proteins, which are present in all living organisms, including plants (Feder and Hofmann 1999). Hsps are produced in response to a number of abiotic stresses that plants encounter within their natural environ- ments. Temperature extremes, high or low light, water deficit and exposure to toxic substances are some of the signals enhancing their synthesis (Wang et al. 2004). During stressful environmental events, these proteins serve to protect proteins against damage, facilitate refolding of damaged proteins and prevent their aggregation. In addi- tion to their function under stress, Hsps play vital roles under normal physiological conditions, so that they are found at significant levels in nonstressed cells, as well, where they are involved in protein folding, assembly, intracellular translocation and degradation (Vierling 1991). Moreover, Hsp genes are expressed at particular stages of the cell cycle and are also developmentally regulated (Lindquist and Craig 1988). Plant Hsp70s are encoded by a multigene family, con- sisting of 14 members in Arabidopsis and 12 in spinach (for example Guy and Li 1998; Sung et al. 2001). The major role of Hsp70s is to protect heat-labile proteins from denaturation. Under normal conditions, Hsp70s facilitate Communicated by M. Rapacz. S. Manitas ˇevic ´ Jovanovic ´(&) Á G. Matic ´ Department of Biochemistry, Sinis ˇa Stankovic ´ Institute for Biological Research, 142 Despot Stefan Blvd, 11000 Belgrade, Serbia e-mail: manitas@ibiss.bg.ac.rs B. Tucic ´ Department of Evolutionary Biology, Sinis ˇa Stankovic ´ Institute for Biological Research, Belgrade, Serbia 123 Acta Physiol Plant DOI 10.1007/s11738-010-0530-x