Enhanced ascorbic acid accumulation in transgenic potato confers tolerance to various abiotic stresses

Abstract

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.

Arabidopsis CSN5B Interacts with VTC1 and Modulates Ascorbic Acid Synthesis

“…Accumulating data indicate that increased AsA content could enhance tolerance to salt stress in plants (Hemavathi et al, 2010;Zhang et al, 2012); indeed, an AsA-deficient mutant showed sensitivity to salt stress (Huang et al, 2005). Therefore, it is reasonable that the higher AsA content in csn5b confers tolerance to salt stress.…”

“…Ascorbic acid (AsA; vitamin C) is an important plant-derived antioxidant and constitutes a major source of dietary vitamin C in humans; in plants, AsA plays important roles in growth, development, and stress responses (Smirnoff and Wheeler, 2000;Hemavathi et al, 2010;Zhang et al, 2012). AsA has been proposed to function as an enzyme cofactor in photosynthesis and the syntheses of ethylene, gibberellins, and anthocyanins.…”

KONJAC1 and 2 Are Key Factors for GDP-Mannose Generation and Affect l-Ascorbic Acid and Glucomannan Biosynthesis in Arabidopsis

“…In addition, AsA level modulates plant growth and development through altering phytohormone and defense signaling (Pastori et al, 2003). It is known that elevated AsA level confers tolerance to abiotic stresses such as salt and heat stress (Hemavathi et al, 2010;Vacca et al, 2004).…”

Biotech Potatoes in the 21st Century: 20 Years Since the First Biotech Potato

“…A half cup (61 g) serving of baked potato provides only about 8 mg of the recommended daily intake of 40-90 mg per day (USDA Nutrient Data Laboratory 2015). However, potato is capable of producing increased levels of ascorbate (Hemavathi et al 2010;Bulley et al 2012), leading to an opportunity to genetically enhance popular varieties to provide additional Vitamin C our diets. Bulley et al (2012) reported an up to threefold increase in ascorbate through the overexpression of a single potato gene, GDP-L-galactose phosphorylase.…”