ABSTRACT
Autophagy plays a key role in the responses to different stress condition in plants. Reactive oxygen species (ROS) are common modulators of stress responses, having both toxic and signaling functions. In this context, the relationship between ROS and autophagy regulation remains unclear, and in some aspects, contradictory. In this study, we employed pharmacological and genetic approaches to investigate the effects of different ROS on the cytoplastic redox state and autophagic flux in Arabidopsis thaliana. Ours results demonstrated that oxidative treatments with H2O2 and MV, which drastically increased the oxidized state of the cytoplasm, reduced the autophagic flux. Conversely, singlet oxygen, which did not have significant effects on the cytoplasmic redox state, increased the autophagic flux. Additionally, our findings indicated that after H2O2 and high light treatments and during the recovery period, the cytoplasm returned to its reduced state, while autophagy was markedly induced. In summary, our study unveils the differential effects of ROS on the autophagic flux, establishing a correlation with the redox state of the cytoplasm. Moreover, it emphasizes the dynamic nature of autophagy in response to oxidative stress and the subsequent recovery period.
HIGHLIGHTS
This research shows the differential effects of reactive oxygen species on autophagic modulation, highlighting their impact on the cytoplasmic redox state. The relationship between ROS and autophagy regulation remains unclear, and in some aspect’s contradictory. Here, we present a comprehensive investigation characterizing the effects of different ROS, such as hydrogen peroxide and singlet oxygen, on the modulation of autophagy in Arabidopsis. In brief, our findings reveal differential impacts on cytoplasmic redox states and autophagic flux, providing insight into the dynamic nature of autophagy, especially in stress and post-stress conditions.
To the best of our knowledge, our work is the first to evaluate autophagic flux both during and after oxidative stress in plants. Our results indicate that this differentiation is crucial when analyzing the effects of oxidative stress on autophagy.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
We have included detailed explanations, limitations, and references regarding the probes used for determining the cytoplasmic redox state in the revised manuscript. We have also included additional controls as well as measurements of the effects of H2O2 on the autophagic flux in roots and mature leaves
ABBREVIATIONS
- ATG
- autophagy genes
- Conc A
- Concanamicina A
- GFP
- green fluorescent protein
- GSH
- reduced glutathione
- GSSG
- oxidized glutathione
- MV
- methyl viologen
- roGFP
- redox-sensitive green fluorescent proteins
- ROS
- reactive oxygen species
