title: Molecular cloning and expression of squalene synthase and 2,3-oxidosqualene cyclase genes in persimmon (Diospyros kaki L.) fruits.
abstract: Oleanolic acid (OA) and ursolic acid (UA) are the main triterpene acids in persimmon fruit, and squalene synthase and 2,3-oxidosqualene cyclases are important enzymes in pentacyclic triterpene biosynthesis. In order to study their relationship, DkSQS and DkOSC were cloned from persimmon fruits in the present study. The full-length cDNA of DkSQS was 1647 bp, containing an open reading frame (ORF) of 1245 bp that encoded a peptide of 415 amino acids (AA). The 3'-end of DkOSC cDNA fragment contained 522 bp, including a partial ORF of 298 bp, a full poly A tail that encoded 98 AA. Two cultivars of persimmon, i.e. cv. Nishimurawase and cv. Niuxinshi, were used to study the content of OA and UA and the related gene expression. Results showed that OA and UA contents changed in both cultivars during fruit development, the difference in cv. Nishimurawase was greater than that in cv. Niuxinshi. The expression of DkSQS and DkOSC had no obvious correlation with the biosynthesis of OA and UA in the flesh. There may be two main reasons. Firstly, different enzymes involved in the biosynthesis of triterpenes and mutual adjustment were existed in different gene expressions. Secondly, it was not clear that the DkOSC cloned in this research belonged to which subfamily. Therefore, the real relationship between triterpenes and DkSQS and DkOSC in persimmon fruits is still to be revealed.
authors.affiliation: College of Horticulture and Plant Protection, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, 48 East Wenhui Road, Yangzhou 225009, People's Republic of China.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Zhou
authors.forename: Daqiu
authors.initials: D
authors.lastname: Zhao
authors.forename: Yanle
authors.initials: Y
authors.lastname: Sheng
authors.forename: Guohua
authors.initials: G
authors.lastname: Liang
authors.forename: Jun
authors.initials: J
authors.lastname: Tao
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D053898:Biosynthetic Pathways / Q000235:genetics; D002681:China; D003001:Cloning, Molecular; D019295:Computational Biology; D018076:DNA, Complementary / Q000235:genetics; D029788:Diospyros / Q000201:enzymology*; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000235:genetics* / Q000378:metabolism; D005638:Fruit / Q000201:enzymology*; D019751:Intramolecular Transferases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009828:Oleanolic Acid; D009841:Oligonucleotides / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D053978:Pentacyclic Triterpenes / Q000096:biosynthesis* / Q000378:metabolism; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014315:Triterpenes; D000097245:Ursolic Acid
chemical_list: D018076:DNA, Complementary; D013186:Farnesyl-Diphosphate Farnesyltransferase; D019751:Intramolecular Transferases; D009828:Oleanolic Acid; D009841:Oligonucleotides; D053978:Pentacyclic Triterpenes; D014315:Triterpenes; D000097245:Ursolic Acid; C021923:cycloartenol synthase