Involvement of the plasma membrane Ca2+-ATPase in the short-term response of Arabidopsis thaliana cultured cells to oligogalacturonides.
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.
Romani
G
G
Istituto di Biofisica del CNR-Sezione di Milano, Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy. giulia.romani@unimi.it
Bonza
M C
MC
Filippini
I
I
Cerana
M
M
Beffagna
N
N
De Michelis
M I
MI
D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000187:drug effects / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D007700:Kinetics; D009844:Oligosaccharides / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
D029681:Arabidopsis Proteins; D009844:Oligosaccharides; D017382:Reactive Oxygen Species; C412763:oligogalacturonic acid; D000252:Calcium-Transporting ATPases; D002118:Calcium