过量表达PTR1和GTPCHI基因对提高植物叶酸含量的研究-生物学、细胞生物学专业论文.docxVIP

兰州大学硕士学位论文高，其次是茎、叶；而G茎中表达量最高，根、叶随后。 兰州大学硕士学位论文 高，其次是茎、叶；而G茎中表达量最高，根、叶随后。 5构建了由CaMV35S启动子驱动GG因的植物 表达载体，并获得了相应的转基因植株。 关键词：拟南芥，烟草，大豆，尸豫』，GTPCHI,叶酸 II 兰州大学硕士学位论文 兰州大学硕士学位论文 Abstract plant foods are the single most important SOtMCe of folate．However,many plant food SOlffCeS such嬲rice，wheat and maize are poor in this vitamin．So far,folate metabolic engineering in f．00d crops is confined to E coli GTP eyclohydrolase I(GTPCHI)， Mammalian GTP cyclohydrolase I(GTPCHI)，A．thaliana GTP cyclohydrolase I (GTPCHI)and Aminodeoxychorismate synthase(ADCS)．1he aim of this study is to elucidate whether Leishmania major PTRI(NADPH-dependent pterin reductase) which reduce oxidized pterins to their bioactive forms and Glycine max folate synthesis pathway ellzyme GTP cyclohydrolase I(GTPCHI)will increaSe folate content in plants(Nicotiana tabacum andA．thaliana)． The main results obtained嬲follows： l Wb constructed plant expression vectors promotered bY double CaMV35S： pCAMBIA3301-PTRland pCAMBIA3301·MT-PTRl(PrRI WaS fused、析m the mitochondria targeting sequence from A．thaliana MDH genO，which WaS transformed into Nicotiana tabacum，to obtain transgenic plants． 2 Systematically study of the PTRl gene from Leishmania WaS carried out on transgenic plant：(1)The analysis by Semi—Quantitative RT-PCR showed that the PTRl which WaS located in eytosol and MT-PTRl which WaS located in Mitochondria WaS expressed in Tobacco．(2)Folate meaSurement WaS conducted 011 young green leaves both尸豫J and MT-PTRl transgenic lines．In young green leaves．the folate content of尸豫．，transgenic lines both in cytosol and Mitochondria WaS 1 085．86，802．1 8 ng／gfw，respectively，and that of the wild type plants WaS 522．65 ng／gfw． 3 Two homologous GTPCHl were isolated by RACE：two complete GTPCHI cDNA sequences were isolated and cloned by RACE．The two homologous GTPCHl were designated as Gand G1engthes at 1 380bp and 1 374bp．Analysis of the amino acid sequences Alig