title: Isolation and characterization of LHT-type plant amino acid transporter gene from Panax ginseng Meyer.
abstract: A lysine histidine transporter (LHT) cDNA was isolated and characterized from the roots of Panax ginseng, designated PgLHT. The cDNA is 1,865 bp with an open reading frame that codes for a protein with 449 amino acids and a calculated molecular mass of 50.6 kDa with a predicted isoelectric point of 8.87. Hydropathy analysis shows that PgLHT is an integral membrane protein with 9 putative membrane-spanning domains. Multiple sequence alignments show that PgLHT shares a high homology with other plant LHTs. The expression profile of the gene was investigated by real-time quantitative polymerase chain reaction during various chemical treatments. PgLHT was up-regulated in the presence of abscisic acid, salicylic acid, methyl jasmonate, NaCl, and amino acids. To further explore the function of PgLHT gene, full-length cDNA of PgLHT was introduced into P. ginseng by Agrobacterium rhizogenes A4. The overexpression of PgLHT in the hairy roots led to an obviously increase of biomass compared to the controls, and after addition of the amino acids, the overexpressed-PgLHT hairy roots grew more rapidly than untreated controls during early stage of the culture cycle. The results suggested that the PgLHT isolated from ginseng might have role in the environmental stresses and growth response.
authors.affiliation: Molecular Biology Research Center, School of Life Sciences, Central South University, Changsha 410078, China ; College of Chemistry and Chemical Engineering, Hunan Institute of Engineering, Xiangtan 411104, China.
authors.forename: Ru
authors.initials: R
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.forename: Hong-Zhe
authors.initials: HZ
authors.lastname: Cao
authors.forename: Xiao-Lei
authors.initials: XL
authors.lastname: Xie
authors.forename: Jing-Jia
authors.initials: JJ
authors.lastname: Huang
authors.forename: Xiang-Hui
authors.initials: XH
authors.lastname: Chen
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Luo
keywords: Abiotic stresses; LHT gene; Panax ginseng; Real-time quantitative polymerase chain reaction