title: Isolation and characterization of a Glutamate decarboxylase (GAD) gene and their differential expression in response to abiotic stresses from Panax ginseng C. A. Meyer.
abstract: Glutamate decarboxylase (GAD) catalyzes the conversion of L-glutamate to γ-aminobutyric acid (GABA). A full-length cDNA encoding GAD (designated as PgGAD) was isolated and characterized from the root of Panax ginseng C. A. Meyer. The length cDNA of PgGAD was 1881 bp and contained a 1491 bp open reading frame (ORF) encoding a glutamate decarboxylase protein of 496 amino acids, possessing a Ser-X-X-Lys active site, which belongs to the GAD group. The deduced amino acid sequence of the PgGAD was classified in the plant GAD family and has 76-85% high similarity with other plants as like petunia, Arabidopsis, tomato. Secondary structure of PgGAD was predicted by using SOPMA software program. Southern blot analysis of genomic DNA suggests that, there is more than one copy of the PgGAD gene. The organ specific gene expression pattern also studied in P. ginseng seedlings, in which the stem showed elevated expression than root, leaf, bud and rhizomes. Along with this, we also confirmed the gene expression of PgGAD under various abiotic stresses like temperature stress, osmotic stress, anoxia, oxidative stress, and mechanical damage. Temporal analysis of gene expression except exposure of oxidative stress revealed an enhanced expression after each stresses. The enzyme activity of PgGAD was stimulated to 2-fold under cold stress.
authors.affiliation: Korean Ginseng Center for Most Valuable Products and Ginseng Genetic Resource Bank, Kyung Hee University, Seocheon, Giheung-gu, Yongin-si, Gyunggi-do, 449-701, Republic of Korea.
authors.forename: Jung-Hye
authors.initials: JH
authors.lastname: Lee
authors.forename: Yu-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Dae-Young
authors.initials: DY
authors.lastname: Jeong
authors.forename: Gayathri
authors.initials: G
authors.lastname: Sathiyaraj
authors.forename: Rama Krishna
authors.initials: RK
authors.lastname: Pulla
authors.forename: Ju-Sun
authors.initials: JS
authors.lastname: Shim
authors.forename: Jun-Gyo
authors.initials: JG
authors.lastname: In
authors.forename: Deok-Chun
authors.initials: DC
authors.lastname: Yang
mesh_terms: D015139:Blotting, Southern; D003001:Cloning, Molecular; D003080:Cold Temperature; D018076:DNA, Complementary / Q000235:genetics; D057075:Enzyme Assays; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D005894:Panax / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D005968:Glutamate Decarboxylase