title: The tomato mutation nxd1 reveals a gene necessary for neoxanthin biosynthesis and demonstrates that violaxanthin is a sufficient precursor for abscisic acid biosynthesis.
abstract: Carotenoid pigments are indispensable for plant life. They are synthesized within plastids where they provide essential functions in photosynthesis. Carotenoids serve as precursors for the synthesis of the strigolactone phytohormones, which are made from β-carotene, and of abscisic acid (ABA), which is produced from certain xanthophylls. Despite the significant progress that has been made in our understanding of the carotenoid biosynthesis pathway, the synthesis of the xanthophyll neoxanthin has remained unknown. We report here on the isolation of a tomato (Solanum lycopersicum) mutant, neoxanthin-deficient 1 (nxd1), which lacks neoxanthin, and on the cloning of a gene that is necessary for neoxanthin synthesis in both tomato and Arabidopsis. The locus nxd1 encodes a gene of unknown function that is conserved in all higher plants. The activity of NXD1 is essential but cannot solely support neoxanthin synthesis. Lack of neoxanthin does not significantly reduce the fitness of tomato plants in cultivated field conditions and does not impair the synthesis of ABA, suggesting that in tomato violaxanthin is a sufficient precursor for ABA production in vivo.
authors: Department of Genetics, Alexander Silberman Institute of Life Sciences, Jerusalem, 91904, Israel.
authors: Hadar
authors: H
authors: Neuman
authors: Navot
authors: N
authors: Galpaz
authors: Francis X
authors: FX
authors: Cunningham
authors: Dani
authors: D
authors: Zamir
authors: Joseph
authors: J
authors: Hirschberg
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D053898:Biosynthetic Pathways; D002338:Carotenoids / Q000096:biosynthesis; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D010788:Photosynthesis; D010937:Plant Growth Regulators / Q000096:biosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation; D016415:Sequence Alignment; D024341:Xanthophylls / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D010937:Plant Growth Regulators; D010940:Plant Proteins; D024341:Xanthophylls; D002338:Carotenoids; C005613:violaxanthin; D000040:Abscisic Acid; C011947:neoxanthin
keywords: Arabidopsis thaliana; Solanum lycopersicum; abscisic acid; carotenoid biosynthesis xanthophyll; gene cloning; photosynthesis