Biogenesis of mitochondria in cauliflower ( Brassica oleracea var. botrytis ) curds subjected to temperature stress and recovery involves regulation of the complexome, respiratory chain activity, organellar translation and ultrastructure

Abstract

The biogenesis of the cauliflower curd mitochondrial proteome was investigated under cold, heat and the recovery. For the first time, two dimensional fluorescence difference gel electrophoresis was used to study the plant mitochondrial complexome in heat and heat recovery. Particularly, changes in the complex I and complex III subunits and import proteins, and the partial disintegration of matrix complexes were observed. The presence of unassembled subunits of ATP synthase was accompanied by impairment in mitochondrial translation of its subunit. In cold and heat, the transcription profiles of mitochondrial genes were uncorrelated. The in-gel activities of respiratory complexes were particularly affected after stress recovery. Despite a general stability of respiratory chain complexes in heat, functional studies showed that their activity and the ATP synthesis yield were affected. Contrary to cold stress, heat stress resulted in a reduced efficiency of oxidative phosphorylation likely due to changes in alternative oxidase (AOX) activity. Stress and stress recovery differently modulated the protein level and activity of AOX. Heat stress induced an increase in AOX activity and protein level, and AOX1a and AOX1d transcript level, while heat recovery reversed the AOX protein and activity changes. Conversely, cold stress led to a decrease in AOX activity (and protein level), which was reversed after cold recovery. Thus, cauliflower AOX is only induced by heat stress. In heat, contrary to the AOX activity, the activity of rotenone-insensitive internal NADH dehydrogenase was diminished. The relevance of various steps of plant mitochondrial biogenesis to temperature stress response and recovery is discussed.

Cold and Heat Stress Diversely Alter Both Cauliflower Respiration and Distinct Mitochondrial Proteins Including OXPHOS Components and Matrix Enzymes

“…In addition, AOX may not to be increased in abundance by certain stress treatments, for example chilling [ 49 , 50 ]. The latter phenomenon was also confirmed in our previous study [ 41 ]; we reported a significant decline in AOX level in cauliflower mitochondria under cold stress and recovery. Overall AOX gene family responses on proteomic and transcriptomic levels were only partially associated and AOX was a suggested target of translational regulation in diverse temperature treatments.…”

“…Although it is known that temperature stress modulates mitochondrial protein activity, level, biogenesis and interactions [ 40 , 41 , 42 ], crucial steps of achieving appropriate coordination during mitochondrial biogenesis in stress need to be further investigated. For instance, Giegé et al [ 43 ] showed that regulation of mitochondrial biogenesis in Arabidopsis cell cultures during sugar starvation seems to be rather coordinated at the complex assembly.…”

Developing Climate-Resilient Chickpea Involving Physiological and Molecular Approaches With a Focus on Temperature and Drought Stresses

“…In cold-tolerant chickpea genotypes, the content of unsaturated fatty acids increased during lowtemperature exposure (10°C for 5 days followed by 4°C for 2 days) (Shahandashti et al, 2013), which possibly contributed toward maintenance of membrane integrity during cold stress. Mitochondria are the most vital cell organelles and play an important role in stress tolerance mechanisms by interacting with energy-dissipating elements such as alternative oxidase (AOX) (Borecky and Vercesi, 2005;Rurek et al, 2015). In optimum conditions, plant cells carry on the cytochromemediated pathway with the help of the mitochondrial electron transfer chain, which results in ATP synthesis by using the proton motive force (Dinakar et al, 2016).…”

The Influence of Statins on the Aerobic Metabolism of Endothelial Cells

“…Solubilized mitochondrial proteins (70-180 µg) were separated in 1.5 mm thick, 3%-11% gradient minigels, and the activities of CI, CII, and CV were detected as described previously [44,45]. To determine the amounts of respiratory complexes with immunoblotting, the BN-PAGE gels were soaked in transfer buffer (39 mM glycine, 0,0375% SDS, 20% ethanol, 48 mM Tris, pH 9.2) for 45 min.…”