Accumulation of dehydrin-like proteins in the mitochondria of cereals in response to cold, freezing, drought and ABA treatment.
BACKGROUND
Dehydrins are known as Group II late embryogenesis abundant proteins. Their high hydrophilicity and thermostability suggest that they may be structure stabilizers with detergent and chaperone-like properties. They are localised in the nucleus, cytoplasm, and plasma membrane. We have recently found putative dehydrins in the mitochondria of some cereals in response to cold. It is not known whether dehydrin-like proteins accumulate in plant mitochondria in response to stimuli other than cold stress.


RESULTS
We have found five putative dehydrins in the mitochondria of winter wheat, rye and maize seedlings. Two of these polypeptides had the same molecular masses in all three species (63 and 52 kD) and were thermostable. Drought, freezing, cold, and exogenous ABA treatment led to higher accumulation of dehydrin-like protein (dlp) 63 kD in the rye and wheat mitochondria. Protein 52 kD was induced by cold adaptation and ABA. Some accumulation of these proteins in the maize mitochondria was found after cold exposition only. The other three proteins appeared to be heat-sensitive and were either slightly induced or not induced at all by all treatments used.


CONCLUSIONS
We have found that, not only cold, but also drought, freezing and exogenous ABA treatment result in accumulation of the thermostable dehydrins in plant mitochondria. Most cryotolerant species such as wheat and rye accumulate more heat-stable dehydrins than cryosensitive species such as maize. It has been supposed that their function is to stabilize proteins in the membrane or in the matrix. Heat-sensitive putative dehydrins probably are not involved in the stress reaction and adaptation of plants.
Borovskii
Genadii B
GB
Institute of Plant Physiology and Biochemistry, Russian Academy of Sciences, Irkutsk-33, P,O,Box 1243, Irkutsk, Russia 664033. gena@sifibr.irk.ru
Stupnikova
Irina V
IV
Antipina
Anna I
AI
Vladimirova
Svetlana V
SV
Voinikov
Victor K
VK
D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects; D003080:Cold Temperature; D004190:Disasters; D002523:Edible Grain / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005615:Freezing; D024101:Mitochondrial Proteins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D012434:Secale / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity; D014908:Triticum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
D024101:Mitochondrial Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C070556:dehydrin proteins, plant; D000040:Abscisic Acid