Early cone-setting in Picea abies var. acrocona is associated with increased transcriptional activity of a MADS-box transcription factor

Conifers normally go through a long juvenile period, for Norway spruce around 20-25 years, before developing male and female cones. We have grown plants from inbred crosses of a naturally occurring spruce mutant (Picea abies var. acrocona). One fourth of the segregating acrocona plants initiate cones already in their second growth cycle; suggesting control by a single locus. The early cone-setting properties of the acrocona mutant were utilized to identify candidate genes involved in vegetative to reproductive phase change in P. abies. Poly(A)+ RNA samples from apical and basal shoots of cone-setting and non-cone-setting plants were subjected to high throughput sequencing (RNA-seq).