Constitutive expression of the cold-regulated Arabidopsis thaliana COR15a gene affects both chloroplast and protoplast freezing tolerance
Constitutive expression of the cold-regulated Arabidopsis thaliana COR15a gene affects both chloroplast and protoplast freezing tolerance
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DOI：
10.1073/pnas.93.23.13404
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发表时间：
1996-11-12
影响因子：
11.1
通讯作者：
Thomashow, MF
中科院分区：
文献类型：
--
作者：
Artus, NN;Uemura, M;Thomashow, MF
植物的冷驯化与编码未知功能的多肽的 COR（倍数调节）基因的表达有关。人们普遍推测这些基因的产物可能在耐冻性中发挥作用。在这里，我们提供了支持这一假设的直接证据。我们发现，拟南芥冷调节基因 COR15a 编码叶绿体靶向多肽，其组成型表达可将未适应环境的植物叶绿体的体内冷冻耐受性提高近 2 摄氏度，几乎是野生型植物冷适应后增加的三分之一。值得注意的是，COR15a 的组成型表达也会影响原生质体的体外冷冻耐受性。在-5至-8摄氏度之间的温度下，从表达COR15a的非驯化转基因植物的叶子中分离的原生质体的存活率高于从非驯化的野生型植物的叶子中分离的原生质体的存活率。在-2到-4摄氏度之间的温度下，COR15a的组成型表达对生存有轻微的负面影响。讨论了这些数据对 COR15a 可能的作用模式的影响。
Cold acclimation in plants is associated with the expression of COR (fold-regulated) genes that encode polypeptides of unknown function. It has been widely speculated that products of these genes might have roles in freezing tolerance. Here we provide direct evidence in support of this hypothesis. We show that constitutive expression of COR15a, a cold-regulated gene of Arabidopsis thaliana that encodes a chloroplast-targeted polypeptide, enhances the in vivo freezing tolerance of chloroplasts in nonacclimated plants by almost 2 degrees C, nearly one-third of the increase that occurs upon cold acclimation of wild-type plants. Significantly, constitutive expression of COR15a also affects the in vitro freezing tolerance of protoplasts. At temperatures between -5 and -8 degrees C, the survival of protoplasts isolated from leaves of nonacclimated transgenic plants expressing COR15a was greater than that of protoplasts isolated from leaves of nonacclimated wild-type plants. At temperatures between -2 and -4 degrees C, constitutive expression of COR15a had a slight negative effect on survival. The implications of these data regarding possible modes of COR15a action are discussed.