Superoxide Dismutase in Arabidopsis: An Eclectic Enzyme Family with Disparate Regulation and Protein Localization

Abstract

A number of environmental stresses can lead to enhanced production of superoxide within plant tissues, and plants are believed to rely on the enzyme superoxide dismutase (SOD) to detoxify this reactive oxygen species. We have identified seven cDNAs and genes for SOD in Arabidopsis. These consist of three CuZnSODs (CSD1, CSD2, and CSD3), three FeSODs (FSD1, FSD2, and FSD3), and one MnSOD (MSD1). The chromosomal location of these seven SOD genes has been established. To study this enzyme family, antibodies were generated against five proteins: CSD1, CSD2, CSD3, FSD1, and MSD1. Using these antisera and nondenaturing-polyacrylamide gel electrophoresis enzyme assays, we identified protein and activity for two CuZnSODs and for FeSOD and MnSOD in Arabidopsis rosette tissue. Additionally, subcellular fractionation studies revealed the presence of CSD2 and FeSOD protein within Arabidopsis chloroplasts. The seven SOD mRNAs and the four proteins identified were differentially regulated in response to various light regimes, ozone fumigation, and ultraviolet-B irradiation. To our knowledge, this is the first report of a large-scale analysis of the regulation of multiple SOD proteins in a plant species.

Analysis of biochemical variations and microRNA expression in wild (Ipomoea campanulata) and cultivated (Jacquemontia pentantha) species exposed to in vivo water stress

“…2d). To further validate the differential accumulation of CuZnSOD (as evident from in-gel activity assay), immunoblot analyses were carried out using polyclonal anti-CSD2 antiserum (Kliebenstein et al 1998). The immunoblot results confirmed a prominent induction in I. campanulata and transient/less induction in J. pentantha under water deficit (Fig.…”

“…In the current study both the species showed rise in the activity of all SOD isoforms in response to water deficit, however it was comparatively higher in I. campanulata. A. thaliana exposed to oxidative stress showed rise in the activity of CuZnSODs, however MnSOD isoforms showed no change (Kliebenstein et al 1998). In Glycyrrhiza uralensis, drought stress induced no change in MnSOD and FeSOD activities; however CuZnSOD showed most abundant activity (Pan et al 2006).…”

“…Drought stress is identified to severely decrease chlorophyll levels whereas it increases the accumulation of anthocyanins, MDA and SODs (Taulavuori et al 2010;Gould 2004;Cruz de Carvalho 2008;Kliebenstein et al 1998). Decreased chlorophyll is recognized to directly affect photosynthesis which plays a vital role in plant growth and development (Chaves et al 2009;Flexas et al 2004;Lawlor and Tezara 2009).…”

“…Isolated proteins were separated on 10 % SDS-PAGE (Laemmli 1970) and electrotransferred onto polyvinylidenedifluoride (PVDF) membrane (Bio-Rad). Membrane was blocked using 5 % non fat dry milk in TBS for 2 h at room temperature and then incubated with antiserum against CuZnSOD (1:2000 dilution) for 2 h at RT (Kliebenstein et al 1998). After washing the membrane with TBST, it was incubated with HRP conjugated secondary antibody (Thermo Scientific).…”

Salicylic acid up-regulates the expression of chloroplastic Cu, Zn-superoxide dismutase in needles of maritime pine (Pinus pinaster Ait.)

“…This family is divided in three classes (each encoded by a small gene family [14]), differing in their active site metal ion (Cu/Zn, Fe and Mn). Cu,Zn-SOD isoforms are structurally unrelated to the remaining groups; most of them form an homodimer and each subunit binds a copper and zinc ion [12].…”