title: Manipulation of light signal transduction as a means of modifying fruit nutritional quality in tomato.
abstract: Fruit constitutes a major component of human diets, providing fiber, vitamins, and phytonutrients. Carotenoids are a major class of compounds found in many fruits, providing nutritional benefits as precursors to essential vitamins and as antioxidants. Although recent gene isolation efforts and metabolic engineering have primarily targeted genes involved in carotenoid biosynthesis, factors that regulate flux through the carotenoid pathway remain largely unknown. Characterization of the tomato high-pigment mutations (hp1 and hp2) suggests the manipulation of light signal transduction machinery may be an effective approach toward practical manipulation of plant carotenoids. We demonstrate here that hp1 alleles represent mutations in a tomato UV-DAMAGED DNA-BINDING PROTEIN 1 (DDB1) homolog. We further demonstrate that two tomato light signal transduction genes, LeHY5 and LeCOP1LIKE, are positive and negative regulators of fruit pigmentation, respectively. Down-regulated LeHY5 plants exhibit defects in light responses, including inhibited seedling photomorphogenesis, loss of thylakoid organization, and reduced carotenoid accumulation. In contrast, repression of LeCOP1LIKE expression results in plants with exaggerated photomorphogenesis, dark green leaves, and elevated fruit carotenoid levels. These results suggest genes encoding components of light signal transduction machinery also influence fruit pigmentation and represent genetic tools for manipulation of fruit quality and nutritional value.
authors.affiliation: Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853, USA.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Sherry
authors.initials: S
authors.lastname: Roof
authors.forename: Zhibiao
authors.initials: Z
authors.lastname: Ye
authors.forename: Cornelius
authors.initials: C
authors.lastname: Barry
authors.forename: Ageeth
authors.initials: A
authors.lastname: van Tuinen
authors.forename: Julia
authors.initials: J
authors.lastname: Vrebalov
authors.forename: Chris
authors.initials: C
authors.lastname: Bowler
authors.forename: Jim
authors.initials: J
authors.lastname: Giovannoni
mesh_terms: D000483:Alleles; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D002338:Carotenoids / Q000378:metabolism; D016923:Cell Death / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000235:genetics; D005638:Fruit / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development; D008027:Light; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009753:Nutritive Value; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D018087:Plastids / Q000502:physiology / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics* / Q000528:radiation effects*
chemical_list: D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C109254:HY5 protein, Arabidopsis; D009687:Nuclear Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D002734:Chlorophyll; D002338:Carotenoids