With or without a Ca2+ signal?: a proteomics approach toward Ca2+-dependent and -independent changes in response to oxidative stress in Arabidopsis thaliana
摘要
Our work identified Ca2+-dependent and -independent changes in protein contents upon oxidative stress, showing that Ca2+ signaling shapes the early oxidative stress response and identifying potential targets for stress resilience research.
AbstractCalcium (Ca2+) and reactive oxygen species (ROS) are key secondary messengers in plant stress signaling, yet their interplay in regulating proteome-wide responses remains poorly understood. We employed label-free quantitative (LFQ) proteomics to investigate Ca2+-dependent and -independent proteome changes in Arabidopsis thaliana leaves upon oxidative stress induced by hydrogen peroxide (H2O2). To dissect the role of Ca2+ signaling, we inhibited H2O2-induced Ca2+ transients by pre-treatment with the Ca2+ influx blocker LaCl3. Throughout all four treatment samples - control, H2O2-treated, LaCl3-treated, H2O2- and LaCl3-treated - we identified a total of 3724 and 3757 proteins after 10 and 30 min, respectively. Of these, 581 proteins showed significant changes in abundance between the 10 min and 909 proteins between the 30 min sample groups. The combined LaCl3 and H2O2 treatment resulted in the highest number of differentially abundant proteins (DAPs), indicating a strong attenuating effect of Ca2+ signaling on the oxidative stress response. By contrast, only 37 and 57 proteins responded to H2O2 alone with distinct subsets of strictly Ca2+-dependent, partially Ca2+-dependent, and Ca2+-independent proteins. Ca2+-independent H2O2-responsive proteins predominantly showed increased abundance, while strictly Ca2+-dependent proteins exhibited decreased abundance, suggesting a role for Ca2+ signaling in protein degradation. Furthermore, three proteins—WLIM1, CYP97C1, and AGAP1—underwent shifts in Ca2+-dependency between the two time points, pointing to a dynamic Ca2+-regulation. This study provides insight into short-term Ca2+-dependent and independent regulation of the Arabidopsis leaf proteome in response to oxidative stress, thereby identifying potential new targets for research on plant stress resilience mechanisms.