title: Identification of genes in the phenylalanine metabolic pathway by ectopic expression of a MYB transcription factor in tomato fruit.
abstract: Altering expression of transcription factors can be an effective means to coordinately modulate entire metabolic pathways in plants. It can also provide useful information concerning the identities of genes that constitute metabolic networks. Here, we used ectopic expression of a MYB transcription factor, Petunia hybrida ODORANT1, to alter Phe and phenylpropanoid metabolism in tomato (Solanum lycopersicum) fruits. Despite the importance of Phe and phenylpropanoids to plant and human health, the pathway for Phe synthesis has not been unambiguously determined. Microarray analysis of ripening fruits from transgenic and control plants permitted identification of a suite of coregulated genes involved in synthesis and further metabolism of Phe. The pattern of coregulated gene expression facilitated discovery of the tomato gene encoding prephenate aminotransferase, which converts prephenate to arogenate. The expression and biochemical data establish an arogenate pathway for Phe synthesis in tomato fruits. Metabolic profiling and ¹³C flux analysis of ripe fruits further revealed large increases in the levels of a specific subset of phenylpropanoid compounds. However, while increased levels of these human nutrition-related phenylpropanoids may be desirable, there were no increases in levels of Phe-derived flavor volatiles.
authors.affiliation: University of Florida, Horticultural Sciences, Gainesville, Florida 32611-0690, USA.
authors.forename: Valeriano
authors.initials: V
authors.lastname: Dal Cin
authors.forename: Denise M
authors.initials: DM
authors.lastname: Tieman
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tohge
authors.forename: Ryan
authors.initials: R
authors.lastname: McQuinn
authors.forename: Ric C H
authors.initials: RC
authors.lastname: de Vos
authors.forename: Sonia
authors.initials: S
authors.lastname: Osorio
authors.forename: Eric A
authors.initials: EA
authors.lastname: Schmelz
authors.forename: Mark G
authors.initials: MG
authors.lastname: Taylor
authors.forename: Miriam T
authors.initials: MT
authors.lastname: Smits-Kroon
authors.forename: Robert C
authors.initials: RC
authors.lastname: Schuurink
authors.forename: Michel A
authors.initials: MA
authors.lastname: Haring
authors.forename: James
authors.initials: J
authors.lastname: Giovannoni
authors.forename: Alisdair R
authors.initials: AR
authors.lastname: Fernie
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Klee
mesh_terms: D000600:Amino Acids, Dicarboxylic / Q000737:chemistry / Q000378:metabolism; D003509:Cyclohexanecarboxylic Acids / Q000737:chemistry / Q000378:metabolism; D053138:Cyclohexenes / Q000737:chemistry / Q000378:metabolism; D005638:Fruit / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D006801:Humans; D018551:Solanum lycopersicum / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D015394:Molecular Structure; D032306:Petunia / Q000235:genetics; D010649:Phenylalanine / Q000378:metabolism*; D010667:Phenylpyruvic Acids / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000637:Transaminases / Q000145:classification / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000737:chemistry / Q000378:metabolism
chemical_list: D000600:Amino Acids, Dicarboxylic; D003509:Cyclohexanecarboxylic Acids; D053138:Cyclohexenes; D010667:Phenylpyruvic Acids; D010936:Plant Extracts; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins; D055549:Volatile Organic Compounds; D014443:Tyrosine; D010649:Phenylalanine; C015478:pretyrosine; D000637:Transaminases; C044954:prephenate aminotransferase; C031606:phenylpyruvic acid; C005550:prephenic acid