A mutant, non-naturally occurring or transgenic plant cell comprising: (i) a polynucleotide comprising, consisting or consisting essentially of a sequence encoding a neoxanthin synthase and having at least 60% sequence identity to SEQ ID NO:1 or SEQ ID No. 6 (ii) a polypeptide encoded by the polynucleotide set forth in (i) (iii) a polypeptide having at least 66% sequence identity to SEQ ID NO:2 or at least 60% sequence identity to SEQ ID No. 7 or (iv) a construct, vector or expression vector comprising the isolated polynucleotide set forth in (i), and wherein the expression or activity of the neoxanthin synthase is modulated as compared to a control or wild type plant.
