Article Figures & Data
Figures
- Figure 1.
Summary of major interactions and consequences of alterations on mitochondrial activity on photosynthesis. Plants obtain the energy they require for growth from ATP produced through mitochondrial respiration and photosynthesis. The export of excess NAD(P)H through the “malate valve” will allow the production of ATP during both photosynthesis and oxidative phosphorylation. The ATP is also needed for the conversion of triose phosphate to Suc. Additionally, the malate (and fumarate) produced by the TCA cycle is transported to the vacuole, where it is stored. By a yet unclear mechanism, the mitochondrial function triggers stomatal movement by controlling organic acid levels in both the vacuole and the apoplast, leading to a relative control of carbon dioxide assimilation. It is also hypothesized that an increased activity of l-galactono-1,4-lactone dehydrogenase, which catalyzes the conversion of l-galactono-1,4-lactone to ascorbate and is coupled to the mitochondrial electron transport chain, leads to an up-regulation of photosynthesis by an unclear mechanism involving the modulation of gene expression in both cytosol and chloroplast, redox regulation, or merely efficient removal of photosynthate to support growth requirements. The dotted arrow represents an unknown mechanism. AOX, Alternative oxidase; e-, electron; GalDH, l-galactono-1,4-lactone dehydrogenase; GL, l-galactono-1,4-lactone; OAA, oxaloacetic acid; Pyr, pyruvate; 1, dicarboxylate transporter; I, II, III, and IV, cytochrome pathway complex of the mitochondrial electron transport chain.
- Figure 2.
Characteristics of tomato plants deficient in the enzymes of the TCA cycle. A, Activity of the target enzyme in the tomato transgenic lines. B, Assimilation rate at 1,000 μmol m−2 s−1. C, Fruit yield based on total dry weight accumulated in the fruits at the end of development. For each set of transgenics, one of the moderately inhibited lines was chosen. For full details, see the respective references. WT, Wild type (S. lycopersicum ‘Moneymaker’); ScoAL, succinyl-CoA ligase; Fum, fumarase; CS, citrate synthase; IDH, isocitrate dehydrogenase; MDH, malate dehydrogenase; ACO, aconitase. The lines used were as follows: succinyl-CoA ligase, RL40; fumarase, FL11; citrate synthase, CS22; isocitrate dehydrogenase, IDH4; malate dehydrogenase, AL21; aconitase, Aco-1. Asterisks indicate values that were determined by Student’s t test to be significantly different (P < 0.05) from the respective wild type.
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- Article
- THE NEED FOR COORDINATION OF CELLULAR ENERGY METABOLISM
- HORSES FOR COURSES: CELL TYPE AND ENVIRONMENTAL VARIANCE IN THE CELLULAR DEPENDENCE OF THE MAJOR PATHWAYS OF ENERGY METABOLISM
- ALTERING PHOTOSYNTHETIC CARBON ASSIMILATION AND YIELD BY TARGETING THE TCA CYCLE
- ALTERING PHOTOSYNTHETIC CARBON ASSIMILATION BY OTHER MITOCHONDRIAL MANIPULATIONS
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