Central role of FaGAMYB in the transition of the strawberry receptacle from development to ripening. Central role of FaGAMYB in the transition of the strawberry receptacle from development to ripening

The study assigns a key regulatory role of FaGAMYB in the initiation of strawberry receptacle ripening and acting upstream of the known regulator ABA. Down-regulation of FaGAMYB caused an arrest in the ripening of receptacle and inhibited colour formation. Consistent with this, several transcription factors associated to the regulation of flavonoids biosynthetic pathway showed altered expression. FaGAMYB silencing also caused a reduction of ABA biosynthesis and sucrose content. Interestingly exogenous ABA application to RNAi transformed receptacle reversed most defects caused by FaGAMYB down53 regulation. Transient silencing of FaGAMYB using RNAi and further determination of changes in (1) global gene expression by RNAseq, and (2) composition of primary and secondary metabolites has been used to investigate the role played by this gene during the development of the receptacle.