Constitutive expression of the cold-regulated Arabidopsis thaliana COR15a gene affects both chloroplast and protoplast freezing tolerance

AUTOR(ES)

Artus, Nancy N.

FONTE

The National Academy of Sciences of the USA

RESUMO

Cold acclimation in plants is associated with the expression of COR (cold-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°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°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°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.

Documentos Relacionados

• Mode of action of the COR15a gene on the freezing tolerance of Arabidopsis thaliana
• Purification and properties of Arabidopsis thaliana COR (cold-regulated) gene polypeptides COR15am and COR6.6 expressed in Escherichia coli.
• A Mitochondrial Complex I Defect Impairs Cold-Regulated Nuclear Gene Expression
• Expression patterns and promoter activity of the cold-regulated gene ci21A of potato.
• The Interaction between Cold and Light Controls the Expression of the Cold-Regulated Barley Gene cor14b and the Accumulation of the Corresponding Protein1