CIP353 encodes an AP2/ERF-domain protein in potato (Solanum tuberosum L.) and responds slowly to cold stress

We isolated the CIP353 cDNA, which encodes a novel cold-inducible protein, from cold-stored tubers of potato (Solanum tuberosum L.). The level of CIP353 transcripts began to increase in tubers 2 weeks after storage at 3degreesC and continued increasing for at least 3 months during storage. This increase was not observed in tubers stored at greater than or equal to9degreesC. The increased level of transcripts in tubers stored at 3 or 6degreesC decreased when the tubers were shifted to 20degreesC. These data suggest that CIP353 is a temperature-dependent and slowly responsive cold-inducible gene of potato. The middle of the deduced amino acid sequence of CIP353 cDNA showed high similarity to the AP2/ERF domain, which occurs in some plant regulatory factors. The deduced protein contained a putative basic nuclear-localization signal and potential acidic activation domains. These data suggest that CIP353 protein is a transcription factor of genes expressed in tubers under long-term storage at low temperatures.