植物的低温蛋白

The cold induced proteins in plants

综述了与植物耐冻性有关的一些植物内源蛋白质或多肽 ,包括低温防护蛋白、抗冻蛋白、植物脱水素、膜关联耐冻性多肽蛋白质。结果表明 ,植物的耐冻性与其低温蛋白 (cold induced proteins)有着密切的关系 ,并指出了抗冻蛋白行使功能的两种可能的作用方式。同时 ,耐冻性与除低温外的其它环境胁迫因子的植物抗性如抗干旱、抗病虫、高盐耐性。

The endogenous polypeptides or proteins that are related to plant tolerance to low temperature, which include cryoprotective proteins, antifreeze proteins, dehydrins and membrane proteins, are reviewed in this paper. These material proteins could also be useful to drought resistance, pathogen and pest resistance, and salt resistance. The cryoprotective proteins could protect isolated thylakoids from plastocyanin release of membrane rupture caused by freeze, which have higher protective activity than sucrose. Antifreeze proteins (AFPs) are mainly located in apoplast and have the effects of thermal hysteresis, ice crystal modification and recrystallization inhibition. Some of them are pathogeonesis-related proteins (PR). In winter rye, seven polypeptides accumulate in the apoplast of cold-acclimated leaves. They are glucanase-like AFPs (GLPs) with 35kDa, 32kDa, chitinase-like AFPs (CLPs) with 35, 28kDa, and thaumatin-like AFPs (TLPs) with 25, 16kDa. Dehydrins are D11 LEA proteins that could be induced by droughts as well as low temperatures and other stress factors. They are boiling-stable and have high conserved Y, S and K segments. Their roles may be serving as molecular chaperone to protect proteins and membranes from denaturation. The membrane-related proteins like GPATs and LTPs play great roles in membrane fluidity and then relate closely to the freeze tolerance of plants. The results showed that plant cold-induced proteins are intimately responsible for plant freeze tolerance. Two modes of the functioning of antifreeze proteins are pointed out in this paper. Many methods and techniques for studying plant cold induced proteins are introduced briefly. We propose that plant resistance to low temperature may result from the total effects of the four types of cold induced proteins of cryoprotective proteins, antifreeze proteins, dehydrins and membrane related proteins, together. In the beginning of cold stress, cell cytoplasm membrane senses stress signal by putative sensor proteins located on cell cytoplasm membrane. The cells synthesize membrane-related proteins like GPATs to maintain membrane fluidity. The initial resistance or adaptation to low temperature is formed. Along with the increase of cold stress, plant synthesizes cryoprotective proteins to maintain the temporary stability of membrane from the rupture. If temperature goes to an even lower status, plants initiate to synthesize antifreeze proteins. These proteins could prevent cells from ice crystallization by the effective function of thermal hysteresis effect, ice crystal modification effect and recrystallization inhibition effect. When temperature is very far below 0℃ and ice crystals have been formed intercellularly or intracellularly in plant cells, some amounts of water flow outside from cells, which result in cell desiccation. At this time plants synthesize dehydrins to protect macromolecules from denaturing, forming the last defense so as to make effect to survive. In ecology, we figure that the study of plant cold induced proteins has great importance in the field of plant-animal interaction if PR AFPs metabolism is well elucidated. The proper induction of defensins of cold-induced proteins could change the relationship between phytophagous animals and plants and then reduces the application of pestcides that have made great environmental pollution due to lavish use of toxin. Plant cold induced proteins may also be functioning in plants in animal taste and in the ecological distribution of plant community. Plants then affect the ecology of phytophagous animals, which includes reproduction, feeding, coupling and mating. In agriculture, plant acclimation and animal acclimation are critical in culture and the cold induced proteins relate the adaptive process. Plant cold proteins can also present clues to The Life Theory of Growth Redundancy in which plant plasticity due to growth reudundancy occupys a big part of important position. We think that the transformation of growth redundancy into proteins involved in cold resistance metabolism is the essenc.