Involvement of the Plasma Membrane Ca²⁺‐ATPase in the Short‐Term Response of Arabidopsis thaliana Cultured Cells to Oligogalacturonides

Abstract

Treatment of Arabidopsis thaliana cells with oligogalacturonides (OG) initiates a transient production of reactive oxygen species (ROS), the concentration of which in the medium peaks after about 20 min of treatment. The analysis of OG effects on Ca (2+) fluxes shows that OG influence both Ca (2+) influx and Ca (2+) efflux (measured as (45)Ca (2+) fluxes) in a complex way. During the first 10 - 15 min, OG stimulate Ca (2+) influx and decrease its efflux, while at successive times of treatment, OG cause an increase of Ca (2+) efflux and a slight decrease of its influx. Treatment with sub- micro M concentrations of eosin yellow (EY), which selectively inhibits the Ca (2+)-ATPase of plasma membrane (PM), completely prevents the OG-induced increase in Ca (2+) efflux. EY also suppresses the transient feature of OG-induced ROS accumulation, keeping the level of ROS in the medium high. The biochemical analysis of PM purified from OG-treated cells indicates that treatment with OG for 15 to 45 min induces a significant decrease in Ca (2+)-ATPase activation by exogenous calmodulin (CaM), and markedly increases the amount of CaM associated with the PM. During the same time span, OG do not influence the expression of At-ACA8, the main isoform of PM Ca (2+)-ATPase in suspension-cultured A. thaliana cells, and of CaM genes. Overall, the reported results demonstrate that the PM Ca (2+)-ATPase is involved in the response of plant cells to OG and is essential in regulation of the oxidative burst.

Flue gas desulfurization gypsum by-products alters cytosolic Ca2 +distribution and Ca2+-ATPase activity in leaf cells of oil sunflower in alkaline soil

“…A change of free calcium concentration might alter the loosely bound calcium in the cell wall and intercellular space, together with the evidence of high total calcium content found in the oil sunflower leaves might be loosely bound calcium and free calcium, indicating that the entering calcium was partially stored in vacuole or bound to pectins in the middle lamella and maintains the cell wall stability and integrity (Hanson 1984;Palta 1996;Hirschi 2004). concentration in cytosol; this notion was in agreement with the result of our cytosolic Ca 2 ' fluorescence intensity and the findings from other groups (Beffagna et al 2000;Sanders et al 2002;Romani et al 2004).…”

Plasma Membrane Calcium ATPases Are Important Components of Receptor-Mediated Signaling in Plant Immune Responses and Development

“…Ca 2+ homeostasis is also controlled through the function of Ca 2+ ATPases, and our data show that FLS2 forms a complex with ACA8. It is possible that FLS2 transphosphorylates the Ca 2+ ATPase to regulate its activity, as ACA10 is differentially phosphorylated upon flg22 treatment (Benschop et al, 2007 (Romani et al, 2004). In line with this assumption, Ca 2+ fluxes triggered by the MAMP cryptogein in N. benthamiana were increased in amplitude and duration when endoplasmic reticulum-localized NbCA1 was silenced (Zhu et al, 2010).…”

“…Likewise, chemical inhibition of Ca 2+ ATPase function resulted in reduced ROS production in response to the fungal MAMP oligogalacturonide, placing ACA proteins upstream of RbohD (Romani et al, 2004). As Rboh proteins contain two EF hand motifs in their N-terminal domains (Ogasawara et al, 2008), an altered Ca 2+ signature in aca8 aca10 plants may impair ROS generation catalyzed by the NADPH oxidases.…”

Polyamines Interact with Hydroxyl Radicals in Activating Ca2+ and K+ Transport across the Root Epidermal Plasma Membranes

“…5, A and B). Stimulation of the active EY-sensitive Ca 2+ efflux across the PM by ROS was reported in a single study on an Arabidopsis cell culture (Romani et al, 2004). It was shown that ROS generated by oligogalacturonide treatment assisted Ca 2+ -ATPase activation by calmodulin.…”

“…1A). Eosine yellow (EY; 0.5 mM), a specific inhibitor of the PM Ca 2+ pump (Romani et al, 2004;Beffagna et al, 2005) and is sensitive to EY (Fig. 1B), suggesting the Ca 2+ -ATPase as a possible candidate (White and Broadley, 2003).…”