The invention provides isolated polynucleotides comprising sequences encoding a u ORF peptides and variants and fragments thereof. The invention also provides constructs and vectors containing the polynucleotides. The invention further provides cells, plant cells and plants transformed with the polynucleotides and constructs. The invention also provides methods of using the polynucleotides to control expression of operably linked polynucleotides. The invention also provides methods of manipulating GDP-L-Galactose phosphorylase (GGP) expression and ascorbate production in plants utilizing the polynucleotides of the invention.
