Increased expression of mitochondrial dysfunction stimulon genes affects chloroplast redox status and photosynthetic electron transfer in Arabidopsis

Abstract

3Mitochondrial retrograde signals control expression of nuclear mitochondrial dysfunction stimulon 2 4 (MDS) genes. Although MDS gene products mostly affect mitochondrial functions, they also 2 5 influence production of reactive oxygen species (ROS) and redox status of chloroplasts. To study 2 6 this inter-organellar interaction, we analysed the response of the Arabidopsis MDS-overexpressor 2 7 mutant rcd1 to methyl viologen (MV), which catalyses electron transfer from Photosystem I (PSI) 2 8 to molecular oxygen, generating ROS in Mehler's reaction. The response of plants to MV was 2 9 investigated by imaging chlorophyll fluorescence in aerobic and hypoxic environments, and by 3 0 membrane inlet mass spectrometry. Hypoxic treatment abolished the effect of MV on 3 1 photosynthetic electron transfer in rcd1, but not in wild type. A similar reaction to hypoxia was 3 2 observed in other MDS-activating lines and treatments. This suggests that MDS gene products 3 3 contribute to oxygen depletion at the PSI electron-acceptor side. In unstressed growth conditions 3 4 this MDS-related effect is likely masked by endogenous oxygen evolution and gas exchange with 3 5

Ascorbate and Thiamin: Metabolic Modulators in Plant Acclimation Responses

“…It is also known that genes encoding proteins associated with the maintenance of the redox homeostasis, such as glutathione reductase, catalases, ascorbate peroxidases, and superoxide dismutases, are affected [9]. Recently an additional key player in the coordination between chloroplast and mitochondrial signaling pathways has been identified by Shapiguzov and coworkers (2019); their results suggest that the nuclear protein radical-induced cell death1 (RCD1) combines the signaling from both organelles in order to govern transcriptional and metabolic process within each organelle [10,11]. RCD1 mediates this regulation by suppressing the abscisic-acid-responsive NAC (ANAC) transcription factors ANAC013 and ANAC017, known as regulators of the mitochondrial dysfunction stimulon (MDS) genes, and also by receiving the ROS signals from the chloroplast underging protein modifications [10,11].…”

Mitochondrial alternative NADH dehydrogenases NDA1 and NDA2 promote survival of reoxygenation stress in Arabidopsis by safeguarding photosynthesis and limiting ROS generation

“…Maintaining this balance may plausibly become particularly important during stress when the formation of ROS in both mitochondria and chloroplasts can increase dramatically. Chloroplastic ROS metabolism of Arabidopsis is controlled by the nuclear‐encoded MDS genes, one of which encodes for AOX1a (Shapiguzov et al ., 2019a). The alternative mETC prevents photoinhibition of PSII under high light and helps oxidize excess NADH (Yamada et al ., 2020).…”