title: Expression of phytoene synthase gene (Psy) is enhanced during fruit ripening of Cara Cara navel orange (Citrus sinensis Osbeck).
abstract: Citrus is an important fruit crop as regards accumulation of carotenoids. In plant carotenoid biosynthesis, phytoene synthase gene (Psy) plays a key role in catalyzing the head-to-head condensation of geranylgeranyl diphosphate molecules to produce colorless phytoene. In the present paper, we reported the phytoene contents determination and characterization of Psy during fruit ripening of "Washington" navel orange and its red-fleshed mutant "Cara Cara". Results showed that phytoene was exclusively accumulated in peel and pulp of "Cara Cara". Although phytoene was observed accumulating with fruit ripening of "Cara Cara", the contents in pulp were 10 times higher than those in peel. The isolated two Psy cDNAs were both 1520 bp in full length, containing 436 deduced amino acid residues, with a different amino acid at 412th. Genomic hybridization results showed that one or two copies might be present in "Cara Cara" and "Washington" genomes. During "Cara Cara" and "Washington" fruit coloration, expression of Psy was observed to be up-regulated, as revealed by tissue specific profiles in the flavedo, albedo, segment membrane and juice sacs. However, Psy expression in albedo of "Cara Cara" was higher than that in "Washington", as evidenced by phytoene accumulation in the peel.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Crop Molecular Breeding, Huazhong Agricultural University, Wuhan, PR China.
authors.forename: Nengguo
authors.initials: N
authors.lastname: Tao
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Hu
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.forename: Yunjiang
authors.initials: Y
authors.lastname: Cheng
authors.forename: Linlin
authors.initials: L
authors.lastname: Guo
authors.forename: Wenwu
authors.initials: W
authors.lastname: Guo
authors.forename: Xiuxin
authors.initials: X
authors.lastname: Deng
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002957:Citrus / Q000254:growth & development / Q000502:physiology*; D017931:DNA Primers; D015870:Gene Expression; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase