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Mitochondria possess transport mechanisms for import of RNA and DNA. Based on import into isolated Solanum tuberosum mitochondria in the presence of competitors, inhibitors or effectors, we show that DNA fragments of different size classes are taken up into plant organelles through distinct channels. Alternative channels can also be activated according to the amount of DNA substrate of a given size class. Analyses of Arabidopsis thaliana knockout lines pointed out a differential involvement of individual voltage-dependent anion channel (VDAC) isoforms in the formation of alternative channels. We propose several outer and inner membrane proteins as VDAC partners in these pathways., (Copyright © 2021 Elsevier B.V. and Mitochondria Research Society. All rights reserved.)

Mitochondrial transcription rate and RNA steady-state levels were examined in shoots of Arabidopsis seedlings. The shoots were treated with inhibitors of complex III and IV of the cytochrome pathway (CP) and with an inhibitor of the alternative oxidase (AOX) of the mitochondrial electron transport chain. The inhibition of AOX and CP complexes III and IV affected transcription and transcript levels in different ways. CP and AOX inhibitors had opposite effects. Our data support the idea that the redox state of the electron transport chain is involved in the regulation of mitochondrial gene expression at transcriptional and post-transcriptional levels., (Copyright © 2014 Elsevier B.V. and Mitochondria Research Society. All rights reserved.)