FaDAM3 and FaDAM4 are candidate genes for the regulation of seasonal dimorphism in cultivated strawberry

Abstract

Cultivated strawberry (Fragaria ananassa) exhibits seasonal dimorphism between the summer and winter seasons. Under the influence of short day conditions, the winter morphology is induced, which includes shorter petioles, smaller and thicker leaves with higher concentrations of chlorophyll and higher density of trichomes. In peach (Prunus persica) the Dormancy-Associated MADS-box (DAM) gene family is involved in the regulation of winter dormancy, which closely resembles strawberry seasonal dimorphism in terms of timing and environmental regulation. In strawberry, six genes exist with close homology to the peach DAM genes. We analyzed the amino acid and coding sequences of these genes, and designated them FaDAM1-4 and FaSVP1-2. We found that there are three pairs of highly similar paralogs within the strawberry genome that exhibit similar expression patterns, although expression levels vary. FaDAM3 and FaDAM4 exhibit expression patterns that are consistent with seasonal dimorphism. We conclude that FaDAM3 and FaDAM4 are candidate genes for the regulation of seasonal dimorphism in strawberry.