The effect of temperature on Antarctic lichen cytochrome and alternative respiratory pathway rates
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ORIGINAL PAPER
The effect of temperature on Antarctic lichen cytochrome and alternative respiratory pathway rates Mikhail Shelyakin1 · Ilya Zakhozhiy1 · Tamara Golovko1 Received: 24 July 2019 / Revised: 25 September 2020 / Accepted: 30 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Respiration is a crucial process that provides all living organisms with energy and metabolites for growth and cellular maintenance. The processes that control respiration in lichens remain poorly understood. We investigated the effects of short-term temperature changes on the respiration rate, as well as the relative contributions of the cytochrome and alternative pathways of thalli from four green-algal lichen species collected from their natural habitats in Antarctica. Lichen respiration was sensitive to short-term temperature increases over a range of 5–35 °C. The total O 2 uptake rate was increased by fourfold, and the mean respiratory coefficient (Q10) decreased from 2.5 to 1.3 as the temperature increased. An increase in temperature from 5 to 15 °C had a positive effect on cytochrome respiration coupled with energy production. Temperatures above 15 °C stimulated the activation of the alternative (energy-dissipating) respiratory pathway. Hyperthermia led to increased O 2 consumption that was not associated with mitochondrial oxidases. The effects of increased temperature on the respiration rates were more pronounced in the bipolar lichens Umbilicaria decussata and Usnea sphacelata than in the Usnea aurantiaco-atra species with a narrower geographical distribution. Keywords Lichens · Antarctica · Temperature · Respiration · Cytochrome and alternative respiratory pathways · Residual respiration
Introduction Lichens are ancient stable entities formed from the symbiotic association between a fungus and a photosynthesizing partner (photobiont) that is a species of green algae and/or cyanobacteria. Green algae supply the heterotrophic mycobiont with reduced carbon in the form of sugar alcohols (ribitol, sorbitol, erythritol), whereas cyanobacteria produce glucose (Elix and Stocker-Wörgötter 2008). The heterotrophic mycobiont accounts for over 90% of the thallus biomass and most of the respiration (Palmqvist et al. 2008).
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00300-020-02758-4) contains supplementary material, which is available to authorized users. * Mikhail Shelyakin [email protected] 1
Institute of Biology of Komi Scientific Centre, Ural Branch of the Russian Academy of Sciences, 28 Kommunisticheskaya Street, Syktyvkar, Komi Republic, Russia 167982
Respiration of the photoautotrophs breaks down photosynthetic products to release energy in the form of ATP, reducing equivalents, metabolizing components, and intermediates necessary for growth and cellular maintenance. In addition to the cytochrome pathway (CP), which is coupled with ATP synthesis, an alternative (energy-dissipating) pathway (AP) of respiration exists
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