Cloning of a cytosolic ascorbate peroxidase gene from Lycium chinense Mill. and enhanced salt tolerance by overexpressing in tobacco.
To evaluate the physiological importance of cytosolic ascorbate peroxidase (APX) in the reactive oxygen species (ROS)-scavenging system, a full-length cDNA clone, named LmAPX, encoding a cytosolic ascorbate peroxidase was isolated from Lycium chinense Mill. using homologous cloning, then the expression of LmAPX under salt stress was investigated. After sequencing and related analysis, the LmAPX cDNA sequence was 965 bp in length and had an open reading frame (ORF) of 750 bp coding for 250 amino acids. Furthermore, the LmAPX sequence was sub-cloned into prokaryotic expression vector pET28a and the recombinant proteins had a high expression level in Escherichia coli. Results from a southern blot analysis indicated that three inserts of this gene existed in the tobacco genome encoding LmAPX. Compared with the control plants (wild-type and empty vector control), the transgenic plants expressing the LmAPX gene exhibited lower amount of hydrogen peroxide (H2O2) and relatively higher values of ascorbate peroxidase activity, proline content, and net photosynthetic rate (Pn) under the same salt stress. These results suggested that overexpression of the LmAPX gene could decrease ROS production caused by salt stress and protect plants from oxidative stress.
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China.
Guangxia
G
Wu
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China. Electronic address: gangwang@tju.edu.cn.
Gang
G
Wang
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China. Electronic address: jijing@tju.edu.cn.
Jing
J
Ji
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
Hailing
H
Gao
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
Wenzhu
W
Guan
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China; Department of Agronomy, Tianjin Agricultural University, Tianjin 300384, People's Republic of China.
Jiang
J
Wu
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
Chunfeng
C
Guan
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China; Yaohua High School, Tianjin 300040, People's Republic of China.
Yurong
Y
Wang
D000595:Amino Acid Sequence; D060387:Ascorbate Peroxidases / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D032305:Lycium / Q000235:genetics*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D055049:Salt Tolerance / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics*
D060387:Ascorbate Peroxidases
Ascorbate peroxidase; Cloning; Overexpression; Reactive oxygen species; Salt stress