REGULAR PAPER Response of plasma membrane H + -ATPase to low temperature in cucumber roots Malgorzata Janicka-Russak • Katarzyna Kabala • Anna Wdowikowska • Gra _ zyna Klobus Received: 29 April 2010 / Accepted: 1 May 2011 / Published online: 3 June 2011 Ó The Botanical Society of Japan and Springer 2011 Abstract The effect of low temperature (LT, 10°C) on modification of plasma membrane (PM) H ? -ATPase (EC 3.6.3.14) activity in cucumber roots was studied. Plants were grown under LT for 3 or 6 days. Some of the plants after 3 days exposure to LT were transferred to control conditions for another 3 days (post-cold, PC). The activity of PM-H ? -ATPase was decreased in plants treated for 3 days with LT. However, the activity of PM-H ? -ATPase was higher in plants treated with LT for a longer time and in PC plants as well. Estimation of transcript levels of cucumber PM-H ? -ATPase in roots indicates that the action of LT involves the gene expression level. The level of PM- H ? -ATPase mRNA was markedly decreased in roots exposed to LT for 3 days. Moreover, the increased H ? - ATPase activity in PM isolated from plants treated for 6 days with LT and from PC plants was positively corre- lated with higher levels of CsHA transcripts. Western blot analysis with an anti-phosphothreonine antibody showed that modification of the activity of PM-H ? -ATPase under LT stress did not result from phosphorylation/depho- sphorylation of the enzyme protein. However, the stimu- lation of PM-H ? -ATPase activity in the case of PC plants could partially have emanated from increased activity of PM NAD(P)H oxidoreductase. In addition, modification of the transcript level of proton pump genes could have resulted from the action of H 2 O 2 . In PC plants, an increase in H 2 O 2 level was observed. Moreover, treatment of plants with H 2 O 2 induced expression of PM H ? -ATPase genes. Keywords H ? -ATPase activity Á Hydrogen peroxide Á Low temperature Á Oxidoreductase Á Plasma membrane Abbreviations BSA Bovine serum albumin BTP Bis-tris propane DAB 3,3 0 -Diaminobenzidine DTT Dithiothreitol EDTA Ethylene diamine tetraacetic acid H 2 O 2 Hydrogen peroxide MES 2-(N-morpholino)ethanesulfonic acid MOPS 3-[N-morpholino]propanesulfonic acid LT Low temperature PM Plasma membrane PC Post-cold PMSF Phenylmethylsulfonyl fluoride PP2A Protein phosphatases type 2A ROS Reactive oxygen species SDS Dodecyl sulphate sodium salt TRIS Hydroxymethylaminomethane Introduction Unpredictable falls in temperature are a common phe- nomenon in a temperate climate. Membranes are most susceptible to damage resulting from LT. An increase in membrane permeability and a change in its viscosity and fluidity result in a decrease of cell turgor due to LT (Guy 1990). Membrane changes at LT concern positional redistribution of saturated and unsaturated fatty acids (Hughes and Dunn 1996). Probably the change in mem- brane fluidity in LT-sensitive species initiates a signal M. Janicka-Russak (&) Á K. Kabala Á A. Wdowikowska Á G. Klobus Department of Plant Physiology, Institute of Plant Biology, University of Wroclaw, Kanonia 6/8, 50-328 Wroclaw, Poland e-mail: russak@biol.uni.wroc.pl 123 J Plant Res (2012) 125:291–300 DOI 10.1007/s10265-011-0438-6