Cytochrome respiration pathway and sulphur metabolism sustain stress tolerance to low temperature in the Antarctic species Colobanthus quitensis

Abstract

Understandingthe strategies employed by plant species that live in extreme environments offersthe possibility to discover stress tolerance mechanisms. We studied thephysiological, antioxidant and metabolic responses to three temperatureconditions (4, 15, and 23°C) of Colobanthusquitensis (CQ), one of the only two native vascular species in Antarctica.We also employed Dianthus chinensis(DC), to assess the effects of the treatments in a non-Antarctic species fromthe same family.-Usingfused LASSO modelling, we associated physiological and biochemical antioxidant responseswith primary metabolism. This approach allowed us to highlight the metabolicpathways driving the response specific to CQ.-Lowtemperature imposed dramatic reductions in photosynthesis (up to 88%) but notin respiration (sustaining rates of 3.0?4.2 µmol CO2 m-2s‑1) in CQ, and no change in the physiological stress parameters wasfound. Its notable antioxidant capacity and mitochondrial cytochromerespiratory activity (20 and two times higher than DC, respectively), whichensure ATP production even at low temperature, was significantly associatedwith sulphur-containing metabolites and polyamines.-Ourfindings potentially open new biotechnological opportunities regarding the roleofantioxidant compounds and respiratory mechanisms associated with sulphurmetabolism instress tolerance strategies to low temperature.