Open AccessMode of action of the COR15a gene on the freezing tolerance of Arabidopsis thaliana
Author(s) -
Peter L. Steponkus,
Matsuo Uemura,
Raymond A. Joseph,
Sarah J. Gilmour,
Michael F. Thomashow
Publication year - 1998
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.95.24.14570
Subject(s) - arabidopsis thaliana , chloroplast membrane , chloroplast stroma , chloroplast , lamellar structure , biophysics , arabidopsis , biology , dehydration , hexagonal phase , membrane , lamellar phase , microbiology and biotechnology , phase (matter) , botany , chemistry , biochemistry , crystallography , thylakoid , gene , hexagonal crystal system , mutant , organic chemistry
Constitutive expression of theco ld-r egulatedCOR15a gene ofArabidopsis thaliana results in a significant increase in the survival of isolated protoplasts frozen over the range of −4.5 to −7°C. The increased freezing tolerance is the result of a decreased incidence of freeze-induced lamellar-to-hexagonal II phase transitions that occur in regions where the plasma membrane is brought into close apposition with the chloroplast envelope as a result of freeze-induced dehydration. Moreover, the mature polypeptide encoded by this gene, COR15am, increases the lamellar-to-hexagonal II phase transition temperature of dioleoylphosphatidylethanolamine and promotes formation of the lamellar phase in a lipid mixture composed of the major lipid species that comprise the chloroplast envelope. We propose that COR15am, which is located in the chloroplast stroma, defers freeze-induced formation of the hexagonal II phase to lower temperatures (lower hydrations) by altering the intrinsic curvature of the inner membrane of the chloroplast envelope.