title: Antifreeze proteins in winter rye are similar to pathogenesis-related proteins.
abstract: The ability to control extracellular ice formation during freezing is critical to the survival of freezing-tolerant plants. Antifreeze proteins, which are proteins that have the ability to retard ice crystal growth, were recently identified as the most abundant apoplastic proteins in cold-acclimated winter rye (Secale cereale L.) leaves. In the experiments reported here, amino-terminal sequence comparisons, immuno-cross-reactions, and enzyme activity assays all indicated that these antifreeze proteins are similar to members of three classes of pathogenesis-related proteins, namely, endochitinases, endo-beta-1,3-glucanases, and thaumatin-like proteins. Apoplastic endochitinases and endo-beta-1,3-glucanases that were induced by pathogens in freezing-sensitive tobacco did not exhibit antifreeze activity. Our findings suggest that subtle structural differences may have evolved in the pathogenesis-related proteins that accumulate at cold temperatures in winter rye to confer upon these proteins the ability to bind to ice.
authors.affiliation: Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
authors.forename: W C
authors.initials: WC
authors.lastname: Hon
authors.forename: M
authors.initials: M
authors.lastname: Griffith
authors.forename: A
authors.initials: A
authors.lastname: Mlynarz
authors.forename: Y C
authors.initials: YC
authors.lastname: Kwok
authors.forename: D S
authors.initials: DS
authors.lastname: Yang
mesh_terms: D000220:Adaptation, Biological; D000595:Amino Acid Sequence; D021301:Antifreeze Proteins; D002688:Chitinases / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification; D003429:Cross Reactions; D005615:Freezing; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology / Q000502:physiology; D007113:Immunity, Innate; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000276:immunology / Q000502:physiology; D006109:Poaceae / Q000502:physiology; D012621:Seasons; D012434:Secale / Q000737:chemistry* / Q000502:physiology; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013549:Sweetening Agents
chemical_list: D021301:Antifreeze Proteins; D006023:Glycoproteins; D010940:Plant Proteins; D013549:Sweetening Agents; C053376:pathogenesis-related proteins, plant; C003427:thaumatin protein, plant; D002688:Chitinases; D004693:Glucan Endo-1,3-beta-D-Glucosidase