J-GLOBAL ID:200904070040677396  Research Project code:0150000412 Update date:Nov. 13, 2001

Molecular mechanisms of the increase in freezing tolerance of plants in relation to membrane cryostability

Study period:1999 - 2003
Organization (1):
Investigating Researcher (2):
Research overview:
Generation of damage by freezing of plant is significantly related to destruction of functions and structures of biological membrane. Damage by freezing is caused, besides temperature stress owing to decrease in temperature itself, through the following processes: irreversible change of biological membrane by dehydration from the cells and surface of the membranes caused by freezing process, destruction by loss in selective permeability or physical deformation and death of cell. Molecular and combined elucidation that analyzes relation between expression of damage mechanism and complicated intracellular variation occurred during acclimating process in detail by dividing into elementary processes is delayed very much. This study is performed by setting two targets using Arabidopsis thaliana as a material. The first target is to analyze in detail the kinetics of the intracellular variation that occurs in the low temperature acclimating process of Arabidopsis thaliana that is attained in a short time (maximum freezing tolerance is attained in 2 to 4 days of low temperature acclimation) and different variation of expression frequency of freezing damage mechanism and investigate the relation comprehensively. Effects of various changes in the biological membranes and cells during the low temperature acclimating process on the behavior of the biological membrane under freezing and dehydration conditions are analyzed on the behavior of the membrane under freezing and dehydration conditions by biophysical method (using fluorescent analysis, NMR and FTIR etc.) by using model system (the system that reconstructs artificial lipid membrane and membrane protein expressed during the low temperature acclimating process) in addition to current physiological and biochemical method. The second target is to analyze prevention method of expression of freezing damage mechanism on the behavior of the biological membrane using the known transgenic body of low temperature inducing genes whose freezing tolerance has been known to increase (for example, transgenic body of DREBIA that is a transcription factor of a low temperature inducing genes) and new transgenic body of freezing tolerance genes prepared in other subject of this study and to evaluate the function of the genes. Specifically, freezing damage mechanism of the transgenic body and natural type is investigated and compared in detail by microscopic observation and freezing survival test and relation with the change in the composition of the biological membrane and the content and composition of intracellular compatible solute caused by introducing foreign genes is analyzed. Further, comparison with the low temperature acclimating treatment usually carried out in a laboratory is performed and the action mechanism of expression of the genes is compared and identified. The results of this study clarify the action mechanism of the individual freezing tolerance related genes and present an important information that enables logical and efficient approach when preparing new crops with increased low temperature tolerance by introducing foreign genes whose trials are increasing recently. As freezing damage is caused by intracellular dehydration, the study also contribute to prepare drying tolerance crops by transgenic technique.
Keywords (6):
plants ,  freezing tolerance ,  freezing injury ,  biomembranes ,  cold-regulated genes ,  cold acclimation
Project name: Systematic Analysis of the Molecular Mechanisms for Acquisition of Cold Tolerance in Plants and Its Application to Molecular Breeding
Project Organization (1):
  • Iwate University
Researcher representative of the project  (1):
  • UEMURA Matsuo
Research program: Promotion of Basic Research Activities for Innovative Biosciences
Research budget: 2001: \17,000,000

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