Functional characterization of the strawberry calcium-dependent protein kinase FvCPK28

FvCPK28 from woodland strawberry (Fragaria vesca) is a calcium-dependent kinase that phosphorylates AtBIK1 and FvBIK1 and restores Arabidopsis cpk28-1 phenotypes.

• Why it matters: CPK28 is known in Arabidopsis thaliana to restrain pattern-triggered immunity and support development, but its Rosaceae counterparts were uncharacterized.
• What they did: Phylogenetics across four Rosaceae species plus Arabidopsis identified CPK28 orthologs; using FvCPK28, the authors tested calcium dependence, in vitro phosphorylation of AtBIK1 and FvBIK1, and in planta association.
• The result: Expressing FvCPK28 in the Arabidopsis cpk28-1 mutant restored stem elongation and immune responses to wild-type levels, supporting conserved growth–defense regulation in strawberry.