Molecular characterization of a cDNA encoding copper/zinc superoxide dismutase from cultured cells of Manihot esculenta.
Superoxide dismutase (SOD) cDNA, mSOD2, encoding cytosolic copper/zinc SOD (CuZnSOD) cDNA was isolated from suspension-cultured cells of cassava (Manihot esculenta Crantz) by cDNA library screening, and its expression was investigated in relation to environmental stress. mSOD2 is 774 bp in length with an open reading frame (ORF) of 152 amino acids, corresponding to a protein of predicted molecular mass 15 kDa and a pI of 5.22. One copy of the mSOD2 gene was found to be present in the cassava genome by Southern analysis using an mSOD2 cDNA-specific probe. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed diverse expression patterns for the mSOD2 gene in various tissues of intact cassava plants, at various stages of the growth in suspension cultures, and in the leaf tissues exposed to different stresses. The mSOD2 gene was highly expressed in suspension-cultured cells and in the stems of intact plants. However, it was expressed at low levels in leaves and roots. During suspension cell growth, the mSOD2 transcript progressively increased during culture. Moreover, the mSOD2 gene in excised cassava leaves responded to various stresses in different ways. In particular, it was highly induced in leaf tissue by several abiotic stresses, including high temperature (37 degrees C), chilling (4 degrees C), methyl viologen (MV) exposure, and wounding treatment. These results indicate that the mSOD2 gene is involved in the antioxidative process triggered by oxidative stress induced by environmental change.
Shin
Seung-Yong
SY
Laboratory of Environmental Biotechnology, Korea Research Institute of Bioscience and Biotechnology, 52 Eoen-dong, Yuseong-gu, Daejeon 305-806, South Korea.
Lee
Haeng-Soon
HS
Kwon
Suk-Yoon
SY
Kwon
Soon-Tae
ST
Kwak
Sang-Soo
SS
D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D015723:Gene Library; D002365:Manihot / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010269:Paraquat / Q000633:toxicity; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D013696:Temperature
D018076:DNA, Complementary; D010940:Plant Proteins; D013482:Superoxide Dismutase; D010269:Paraquat