Mutation of the Atypical Kinase ABC1K3 Partially Rescues the PROTON GRADIENT REGULATION 6 Phenotype in Arabidopsis thaliana

Tissue-type specific accumulation of the plastoglobular proteome, transcriptional networks and plastoglobular functions

“…At the highest stringency network (LS ≥ 7), there were 10 edges, with three from glutathione reductase connecting to FRED2, ABC1K3 and ABC1K6. This supports the concept that PGs are part of the redox and antioxidative network, likely able to accept and donate electron through the pool of PQ and other isoprenoidsfor more discussion see (Havaux, 2020) (Pralon et al, 2020;Pralon et al, 2019) (van Wijk andKessler, 2017) (Kumar et al, 2020).…”

“…The PG-thylakoid connection thus allows exchange of lipophilic molecules (in particular isoprenoids, as well as fatty acids and membrane lipids), between the thylakoid and PG, whereas PG proteins have access to these small molecules. This allows bidirectional trafficking of small molecules such as phytol, PQ9, PC8, and tocopherols to adjust to the demands of the thylakoid electron transport chain, as demonstrated in the ABC1K1 and ABC1K3 mutants (Lundquist et al, 2013;Pralon et al, 2020;Pralon et al, 2019). Importantly, due to the high amount of PQ9 (and a lesser degree PC8 and tocopherols), the PGs also serve as a plastid oxidation-reduction buffer and redox exchange site, thus supporting ROS defense and oxidation-reduction reactions in metabolism (Havaux, 2020).…”

Growth Temperature Influence on Lipids and Photosynthesis in Lepidium sativum

“…The crowded thylakoid membrane poses major limitations to the mobility of PQ and therefore may physically hamper its oxidation in the dark (Tremmel et al, 2003). Considering this, the differences in the galactolipid profile (Figure 5) and the change in the photosynthetic protein accumulation (Figure 4) observed at 10 • C may be functional in facilitating PQ mobility and therefore its oxidation by PTOX (Pralon et al, 2020). Furthermore, the accumulation of plastochromanol, which appears to be tendentially higher at 10 • C than at 30 • C, would allow to contrast more efficiently membrane lipid peroxidation (Figure 5; Nowicka et al, 2013).…”

“…Each batch of plants was kept in the dark for at least 10 min before the measurements. Room temperature chlorophyll fluorescence was measured with a MF800 Fluorcam (Photon System Instrument, Czechia) 1 employing a personalized light protocol (Pralon et al, 2020). The protocol is composed of blue light (470 nm) steps of 1 min with increasing intensity (35, 125, 315, 500, 690, and 875 µmol photons m −2 s −1 of PAR intensity).…”

“…Therefore, the relative fluorescence at 3 ms (V J ) and its kinetics after a dark or far red-light period of increasing length were taken as a proxy of the PQ oxidation over time. In the dark, the PQ oxidation is performed by electron pathways alternative to the photosynthetic electron transport chain, mostly via the plastid terminal oxidase (PTOX) (Pralon et al, 2020). Conversely, far-red will activate PSI allowing a photochemical oxidation of PQ (Rochaix, 2011).…”