Our results indicated that both genes are light-regulated in the flavedo and reinforce the conclusion that the l-galacturonic acid pathway appears to be an important supplier of precursors and plays a crucial role in the regulation of AsA concentration in Citrus fruit. In this context, the presence of two light-responsive boxes in the promoter region of GalUR gene has been described in strawberry and transient expression assays indicated that light is a requirement for the activity of this promoter in this fruit [49] and an important factor regulating this pathway. Similarly, we have found several light-responsive motifs in the promoter regions of both GalUR8 and GalUR12 isoforms (data not shown), however, additional studies are required to confirm their functionality.