Treatments with Diquat Reveal the Relationship between Protein Phosphatases (PP2A) and Oxidative Stress during Mitosis in <i>Arabidopsis thaliana</i> Root Meristems
Adrienn Kelemen,
Tamás Garda,
Zoltán Kónya,
Ferenc Erdődi,
László Ujlaky-Nagy,
Gabriella Petra Juhász,
Csongor Freytag,
Márta M-Hamvas,
Csaba Máthé
Affiliations
Adrienn Kelemen
Plant Cell and Developmental Biology Research Group, Department of Botany, Faculty of Science and Technology, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Tamás Garda
Plant Cell and Developmental Biology Research Group, Department of Botany, Faculty of Science and Technology, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Zoltán Kónya
Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Ferenc Erdődi
Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
László Ujlaky-Nagy
Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Gabriella Petra Juhász
Plant Cell and Developmental Biology Research Group, Department of Botany, Faculty of Science and Technology, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Csongor Freytag
Plant Cell and Developmental Biology Research Group, Department of Botany, Faculty of Science and Technology, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Márta M-Hamvas
Plant Cell and Developmental Biology Research Group, Department of Botany, Faculty of Science and Technology, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Csaba Máthé
Plant Cell and Developmental Biology Research Group, Department of Botany, Faculty of Science and Technology, University of Debrecen, Egyetem sq. 1, 4032 Debrecen, Hungary
Reversible protein phosphorylation regulates various cellular mechanisms in eukaryotes by altering the conformation, activity, localization, and stability of substrate proteins. In Arabidopsis thaliana root meristems, histone post-translational modifications are crucial for proper cell division, and they are also involved in oxidative stress signaling. To investigate the link between reactive oxygen species (ROS) and mitosis, we treated various Arabidopsis genotypes, including wild-types and mutants showing dysfunctional PP2A, with the ROS-inducing herbicide diquat (DQ). Studying the c3c4 double catalytic subunit mutant and fass regulatory subunit mutants of PP2A provided insights into phosphorylation-dependent mitotic processes. DQ treatment reduced mitotic activity in all genotypes and caused early mitotic arrest in PP2A mutants, likely due to oxidative stress-induced damage to essential mitotic processes. DQ had a minimal effect on reversible histone H3 phosphorylation in wild-type plants but significantly decreased phospho-histone H3 levels in PP2A mutants. Following drug treatment, the phosphatase activity decreased only in the stronger phenotype mutant plants (fass-5 and c3c4). Our findings demonstrate that (i) the studied PP2A loss-of-function mutants are more sensitive to increased intracellular ROS and (ii) DQ has indirect altering effects of mitotic activities and histone H3 phosphorylation. All these findings underscore the importance of PP2A in stress responses.
