Cloning and characterization of the astaxanthin biosynthetic gene encodingphytoene desaturase of Xanthophyllomyces dendrorhous

The first carotenoid biosynthetic gene from the basidiomycetous yeast Xanth ophyllomyces dendrorhous was isolated by heterologous complementation in Es cherichia coil. The isolated gene, denominated as crtl, was found to encode for phytoene desaturase. The coding region is interrupted by 11 introns. T he deduced amino acid sequence showed significant homology with its bacteri al and eukaryotic counterparts, especially those of fungal origin. A plasmi d containing the geranylgeranyl diphosphate synthase and phytoene synthase encoding genes from Erwinia uredovora was introduced in E. coli together wi th the phytoene desaturase encoding cDNA from X. dendrorhous. As a result, lycopene accumulation was observed in these transformants. We conclude that in X, dendrorhous the four desaturase steps, by which phytoene is converte d into lycopene, are carried out by a single gene product. (C) 1999 John Wi ley & Sons, Inc.