Fission and Fusion of Plant Mitochondria, and Genome Maintenance

Arimura, Shin‐ichi

doi:10.1104/pp.17.01025

Cited by 79 publications

(93 citation statements)

References 116 publications

(167 reference statements)

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“…In mammalian cells, mitochondrial hyperfusion is associated with increased ATP production while mitochondrial fragmentation (fission) is associated with stress, membrane depolarization and mitochondrial dysfunction (Liesa & Shirihai, ; Morita et al, ; Westermann, ). In contrast, we show here that fragmented mitochondria in TOR kinase inhibited cells in C. reinhardtii is associated with the upregulation of mitochondrial functions (Figure A–E; Figure ), which is consistent with the findings in plants where mitochondrial fission was dominantly associated with stress (Arimura, ). Such fragmentation may further provide higher respiratory activity, heightened energy supply, and ATP production in the cells.…”

Section: Discussionsupporting

confidence: 91%

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Upadhyaya

Rao

2019

Plant Direct

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While the role of TOR kinase in the chloroplast biogenesis and transcriptional regulation of photosynthesis is well documented in Arabidopsis, the functional relevance of this metabolic sensor kinase in chloroplast–mitochondria cross talk is unknown. Using Chlamydomonas reinhardtii as the model system, we demonstrate the role of TOR kinase in the regulation of chloroplast and mitochondrial functions: We show that TOR kinase inhibition impairs the maintenance of high ETR associated with PSII and low NPQ and inhibits efficient state transitions between PSII and PSI. While compromised photosynthetic functions are observed in TOR kinase inhibited cells, same conditions lead to augmentation in mitochondrial basal respiration rate by twofold and concomitantly a rise in ATP production. Interestingly, such upregulated mitochondrial functions in TOR‐inhibited cells are mediated by fragmented mitochondria via upregulating COXIIb and downregulating Hxk1 and AOX1 protein levels. We propose that TOR kinase may act as a sensor that counter‐regulates chloroplast versus mitochondrial functions in a normal C. reinhardtii cell.

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Section: Discussionsupporting

confidence: 91%

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Upadhyaya

Rao

2019

Plant Direct

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“…2, C and D). Given that mitochondrial dynamics have been observed in various plants (Arimura, 2018), the morphological similarities observed in the chondriomes of both large and nonlarge mitochondria in microsporophyll cells implies that they might be derived from the consecutive fission and fusion of mitochondria, and thus, their function, including cellular respiration, might be similar. Interestingly, the shape of the mitochondria in C. revoluta microsporophylls was very similar to that observed in the appendix of Sauromatum guttatum inflorescences during its thermogenic stage (Skubatz and Kunkel, 2000).…”

Section: The Correlation Between Mitochondrial Morphology and Energy mentioning

confidence: 99%

“…In the shoot apical meristem of Arabidopsis, very large and tentaculate/ cage-like mitochondria have been located in close proximity to the nucleus, but such a distinctive mitochondrial structure has not been observed in the root apical meristem cells, suggesting that such a unique type of mitochondrion may not be required to satisfy the energy needs of meristematic cells (Seguí-Simarro et al, 2008). Such an elongated or enlarged mitochondrial structure in those plants might be related to mitochondrial DNA replication/recombination rather than energy demand, to provide a kind of quality control for mitochondrial populations in the new generation (Rose and McCurdy, 2017;Arimura, 2018).…”

Section: Mitochondria With Distinctive Morphology In More General Plamentioning

confidence: 99%

Alternative Oxidase Capacity of Mitochondria in Microsporophylls May Function in Cycad Thermogenesis

Ito‐Inaba

Sato

et al. 2019

Plant Physiol.

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Cone thermogenesis is a widespread phenomenon in cycads and may function to promote volatile emissions that affect pollinator behavior. Given their large population size and intense and durable heat-producing effects, cycads are important organisms for comprehensive studies of plant thermogenesis. However, knowledge of mitochondrial morphology and function in cone thermogenesis is limited. Therefore, we investigated these mitochondrial properties in the thermogenic cycad species Cycas revoluta. Male cones generated heat even in cool weather conditions. Female cones produced heat, but to a lesser extent than male cones. Ultrastructural analyses of the two major tissues of male cones, microsporophylls and microsporangia, revealed the existence of a population of mitochondria with a distinct morphology in the microsporophylls. In these cells, we observed large mitochondria (cross-sectional area of 2 mm 2 or more) with a uniform matrix density that occupied .10% of the total mitochondrial volume. Despite the size difference, many nonlarge mitochondria (cross-sectional area ,2 mm 2 ) also exhibited a shape and a matrix density similar to those of large mitochondria. Alternative oxidase (AOX) capacity and expression levels in microsporophylls were much higher than those in microsporangia. The AOX genes expressed in male cones revealed two different AOX complementary DNA sequences: CrAOX1 and CrAOX2. The expression level of CrAOX1 mRNA in the microsporophylls was 100 times greater than that of CrAOX2 mRNA. Collectively, these results suggest that distinctive mitochondrial morphology and CrAOX1-mediated respiration in microsporophylls might play a role in cycad cone thermogenesis.

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“…The mechanism for mitochondrial fusion and fission has been demonstrated in eukaryotes such as yeast, mammals, red algae, and land plants (Arimura, 2018). Mitochondrial fission largely requires the function of dynamin-related proteins, which have GTPase activity for the scission of vesicles from membrane.…”

Section: Mitochondrial Dynamics For Pollen Developmentmentioning

confidence: 99%

Mitochondrial Dynamics for Pollen Development

Izumi

2019

Plant Physiol.

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Fission and Fusion of Plant Mitochondria, and Genome Maintenance

Cited by 79 publications

References 116 publications

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Alternative Oxidase Capacity of Mitochondria in Microsporophylls May Function in Cycad Thermogenesis

Mitochondrial Dynamics for Pollen Development

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