Identification of a novel gene coding for neoxanthin synthase from Solanumtuberosum

The polymerase chain reaction analysis of potato plants, transformed with c apsanthin capsorubin synthase ccs, revealed the presence of a highly relate d gene. The cloned cDNA showed at the protein level 89.6% identity to CCS, This suggested that the novel enzyme catalyzes a mechanistically similar re action, Such a reaction is represented by neoxanthin synthase (NXS), formin g the xanthophyll neoxanthin, a direct substrate for abscisic acid formatio n. The function of the novel enzyme could be proven by transient expression in plant protoplasts and high performance liquid chromatography analysis, The cloned NXS was imported in vitro into plastids, the compartment of caro tenoid biosynthesis. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.