Detalle de: Central role of FaGAMYB in the transition of the strawberry receptacle from development to ripening

Summary The receptacle of the strawberry ( Fragaria × ananassa ) fruit accounts for the main properties of the ripe fruit for human consumption. As it ripens, it undergoes changes similar to other fruits in sugar : acid ratio, volatile production and cell wall softening. However, the main regulators of this process have not yet been reported. The white stage marks the initiation of the ripening process, and we had previously reported a peak of expression for a Fa GAMYB gene. Transient silencing of Fa GAMYB using RNA i and further determination of changes in global gene expression by RNA seq, and composition of primary and secondary metabolites have been used to investigate the role played by this gene during the development of the receptacle. Down‐regulation of Fa GAMYB caused an arrest in the ripening of the receptacle and inhibited colour formation. Consistent with this, several transcription factors associated with the regulation of flavonoid biosynthetic pathway showed altered expression. Fa GAMYB silencing also caused a reduction of ABA biosynthesis and sucrose content. Interestingly, exogenous ABA application to the RNA I‐transformed receptacle reversed most defects caused by Fa GAMYB down‐regulation. The study assigns a key regulatory role to Fa GAMYB in the initiation of strawberry receptacle ripening and acting upstream of the known regulator ABA .