Abstract
BackgroundThe development of chilling and freezing injury symptoms in plants is known to frequently coincide with peroxidation of free fatty acids. Mitochondria are one of the major sources of reactive oxygen species during cold stress. Recently it has been suggested that uncoupling of oxidation and phosphorylation in mitochondria during oxidative stress can decrease ROS formation by mitochondrial respiratory chain generation. At the same time, it is known that plant uncoupling mitochondrial protein (PUMP) and other UCP-like proteins are not the only uncoupling system in plant mitochondria. All plants have cyanide-resistant oxidase (AOX) whose activation causes an uncoupling of respiration and oxidative phosphorylation. Recently it has been found that in cereals, cold stress protein CSP 310 exists, and that this causes uncoupling of oxidation and phosphorylation in mitochondria.ResultsWe studied the effects of CSP 310-like native cytoplasmic proteins from a number of cereal species (winter rye, winter wheat, Elymus and maize) on the energetic activity of winter wheat mitochondria. This showed that only CSP 310 (cold shock protein with molecular weight 310 kD) caused a significant increase of non-phosphorylative respiration. CSP 310-like proteins of other cereals studied did not have any significant influence on mitochondrial energetic activity. It was found that among CSP 310-like proteins only CSP 310 had prooxidant activity. At the same time, Elymus CSP 310-like proteins have antioxidant activity. The study of an influence of infiltration by different plant uncoupling system activators (pyruvate, which activates AOX, and linoleic acid which is a substrate and activator for PUMP and CSP 310) showed that all of these decreased lipid peroxidation during cold stress.ConclusionsDifferent influence of CSP 310-like proteins on mitochondrial energetic activity and lipid peroxidation presumably depend on the various subunit combinations in their composition. All the plant cell systems that caused an uncoupling of oxidation and phosphorylation in plant mitochondria can participate in plant defence from oxidative damage during cold stress.
Highlights
The development of chilling and freezing injury symptoms in plants is known to frequently coincide with peroxidation of free fatty acids
An addition to incubated mitochondria immunochemically related to CSP 310 proteins from Elymus and winter wheat failed to result in any significant changes in their activity
So, based on the data obtained we can conclude that during cold stress all the studied winter wheat uncoupling systems can be involved in plant defense against oxidative stress
Summary
The development of chilling and freezing injury symptoms in plants is known to frequently coincide with peroxidation of free fatty acids. It has been suggested that uncoupling of oxidation and phosphorylation in mitochondria during oxidative stress can decrease ROS formation by mitochondrial respiratory chain generation. It has been found that in cereals, cold stress protein CSP 310 exists, and that this causes uncoupling of oxidation and phosphorylation in mitochondria. Skulachev supposed that uncoupling of oxidation and phosphorylation in mitochondria during oxidative stress could decrease ROS generation by mitochondrial respiratory chain [10] This point of view was supported by recent studies of plant UCP-like uncoupling proteins such as PUMP and others. All the plants have such a mechanism in mitochondria as alternative cyanide-resistant oxidase (AOX) whose activation during cold stress causes uncoupling of respiration and oxidative phosphorylation [13]. It is interesting to determine what CSP 310 activity, prooxidant or antioxidant is the most pronounced in whole winter wheat shoots during cold stress
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