Enhanced ascorbic acid accumulation in transgenic potato confers tolerance to various abiotic stresses.
L-ascorbic acid (Vitamin C, AsA) is an important component of human nutrition. Plants and several animals can synthesize their own ascorbic acid, whereas humans lack the gene essential for ascorbic acid biosynthesis and must acquire from their diet. In the present study, we developed transgenic potato (Solanum tuberosum L. cv. Taedong Valley) over-expressing L-gulono-gamma-lactone oxidase (GLOase gene; NCBI Acc. No. NM022220), isolated from rat cells driven by CaMV35S constitutive promoter that showed enhanced AsA accumulation. Molecular analyses of four independent transgenic lines performed by PCR, Southern and RT-PCR revealed the stable integration of the transgene in the progeny. The transformation frequency was ca. 7.5% and the time required for the generation of transgenic plants was 6-7 weeks. Transgenic tubers showed significantly enhanced AsA content (141%) and GLOase activity as compared to untransformed tubers. These transgenics were also found to withstand various abiotic stresses caused by Methyl Viologen (MV), NaCl or mannitol, respectively. The T(1) transgenic plants exposed to salt stress (100 mM NaCl) survived better with increased shoot and root length when compared to untransformed plants. The elevated level of AsA accumulation in transgenics was directly correlated with their ability to withstand abiotic stresses. These results further demonstrated that the overexpression of GLOase gene enhanced basal levels of AsA in potato tubers and also the transgenics showed better survival under various abiotic stresses.
Hemavathi
Department of Molecular Biotechnology, Konkuk University, Seoul, South Korea.
Upadhyaya
Chandrama Prakash
CP
Akula
Nookaraju
N
Young
Ko Eun
KE
Chun
Se Chul
SC
Kim
Doo Hwan
DH
Park
Se Won
SW
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D001483:Base Sequence; D024861:Genetic Enhancement / Q000379:methods*; D018869:Heat-Shock Response / Q000502:physiology*; D050544:L-Gulonolactone Oxidase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified / Q000502:physiology*; D051381:Rats; D011198:Solanum tuberosum / Q000502:physiology*
D050544:L-Gulonolactone Oxidase; D001205:Ascorbic Acid