Phytochrome‐mediated regulation of plant respiration and photorespiration

Abstract

The expression of genes encoding various enzymes participating in photosynthetic and respiratory metabolism is regulated by light via the phytochrome system. While many photosynthetic, photorespiratory and some respiratory enzymes, such as the rotenone-insensitive NADH and NADPH dehydrogenases and the alternative oxidase, are stimulated by light, succinate dehydrogenase, subunits of the pyruvate dehydrogenase complex, cytochrome oxidase and fumarase are inhibited via the phytochrome mechanism. The effect of light, therefore, imposes limitations on the tricarboxylic acid cycle and on the mitochondrial electron transport coupled to ATP synthesis, while the non-coupled pathways become activated. Phytochrome-mediated regulation of gene expression also creates characteristic distribution patterns of photosynthetic, photorespiratory and respiratory enzymes across the leaf generating different populations of mitochondria, either enriched by glycine decarboxylase (in the upper part) or by succinate dehydrogenase (in the bottom part of the leaf).

Possible Roles of Near-infrared Light on the Photosynthesis in <i>Synechocystis</i> sp. PCC6803 under Solar Simulating Artificial Light

“…3c) performed in the step-wise series of NIR removal, Synechocystis cells regained the photosynthetic performance by eliminating the most NIR (wavelengths, 710 nm; Fig. 3b), suggesting that 710 750 nm band may include NIR components inhibitory to photosynthesis possibly corresponding to the absorption band for bacterial phytochrome (Igamberdiev et al, 2014).…”

The origin of cytosolic ATP in photosynthetic cells

“…In particular, an increased NADH/NAD + ratio can reduce the flux of carbon through the TCA cycle via inhibition of pyruvate dehydrogenase complex (PDC) and both NAD‐ and NADP‐dependent isocitrate dehydrogenases (ICDH) as indicated in Fig. , and also potentially by light inhibition of succinate dehydrogenase and fumarase gene expression (Igamberdiev et al ) and thioredoxin‐mediated inhibition of these enzymes (Daloso et al ). This can be an important aspect for the operation of a partial TCA cycle in the light (Hurry et al , Sweetlove et al ) and lead to export of citrate to the cytosol.…”

Cisgenic overexpression of cytosolic glutamine synthetase improves nitrogen utilization efficiency in barley and prevents grain protein decline under elevated CO2

“…In most plant species, GS occurs as a single isoform in the chloroplast (GS2) and up to five isoforms in the cytosol (GS1; Swarbreck et al ., ). GS2 is mainly involved in assimilation of NH 4 + originating from NO 3 − reduction and photorespiration (Brestic et al ., ; Igamberdiev et al ., ; Pérez‐Delgado et al ., ). Barley mutants lacking GS2 were unable to grow under normal atmospheric conditions as they were not able to re‐assimilate photorespiratory ammonium and accumulated relatively high levels of ammonium in the leaves (Blackwell et al ., ; Wallsgrove et al ., ).…”