Characterization of a strawberry cDNA clone homologous to calcium‐dependent protein kinases that is expressed during fruit ripening and affected by low temperature

A full‐length cDNA clone (FaCDPK1) encoding a calcium‐dependent protein kinase (CDPK) has been isolated from a strawberry fruit cDNA library. FaCDPK1 contains the basic features of CDPKs: a catalytic kinase domain linked to a regulatory calmodulin‐like domain by a junction sequence that has been shown to act as an autoinhibitory pseudosubstrate. Although the calmodulin‐like domain of CDPKs typically contains four EF‐hand calcium‐binding motifs, FaCDPK1 was predicted to contain only three EF‐hand motifs. FaCDPK1 gene expression was observed in roots, stolons, meristems, flowers, and leaves. FaCDPK1 mRNA was not detected in young fruits, but accumulated as fruit turned to white, suggesting a role for this gene in the developing strawberry fruit. In ripe fruit the levels of transcript increased in response to low temperature.