Plastid-Expressed Betaine Aldehyde Dehydrogenase Gene in Carrot Cultured Cells, Roots, and Leaves Confers Enhanced Salt Tolerance
Open Access
- 1 September 2004
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 136 (1), 2843-2854
- https://doi.org/10.1104/pp.104.045187
Abstract
Salinity is one of the major factors that limits geographical distribution of plants and adversely affects crop productivity and quality. We report here high-level expression of betaine aldehyde dehydrogenase (BADH) in cultured cells, roots, and leaves of carrot (Daucus carota) via plastid genetic engineering. Homoplasmic transgenic plants exhibiting high levels of salt tolerance were regenerated from bombarded cell cultures via somatic embryogenesis. Transformation efficiency of carrot somatic embryos was very high, with one transgenic event per approximately seven bombarded plates under optimal conditions. In vitro transgenic carrot cells transformed with the badh transgene were visually green in color when compared to untransformed carrot cells, and this offered a visual selection for transgenic lines. BADH enzyme activity was enhanced 8-fold in transgenic carrot cell cultures, grew 7-fold more, and accumulated 50- to 54-fold more betaine (93–101 μmol g−1 dry weight of β-Ala betaine and Gly betaine) than untransformed cells grown in liquid medium containing 100 mm NaCl. Transgenic carrot plants expressing BADH grew in the presence of high concentrations of NaCl (up to 400 mm), the highest level of salt tolerance reported so far among genetically modified crop plants. BADH expression was 74.8% in non-green edible parts (carrots) containing chromoplasts, and 53% in proplastids of cultured cells when compared to chloroplasts (100%) in leaves. Demonstration of plastid transformation via somatic embryogenesis utilizing non-green tissues as recipients of foreign DNA for the first time overcomes two of the major obstacles in extending this technology to important crop plants.Keywords
This publication has 77 references indexed in Scilit:
- Generation of marker-free plastid transformants using a transiently cointegrated selection geneNature Biotechnology, 2004
- A chloroplast transgenic approach to hyper‐express and purify Human Serum Albumin, a protein highly susceptible to proteolytic degradationPlant Biotechnology Journal, 2003
- Molecular strategies for gene containment in transgenic cropsNature Biotechnology, 2002
- SALT AND DROUGHT STRESS SIGNAL TRANSDUCTION IN PLANTSAnnual Review of Plant Biology, 2002
- Expression of an Antimicrobial Peptide via the Chloroplast Genome to Control Phytopathogenic Bacteria and FungiPlant Physiology, 2001
- Expression of the native cholera toxin B subunit gene and assembly as functional oligomers in transgenic tobacco chloroplasts11Edited by N.-H. ChuaJournal of Molecular Biology, 2001
- Genetic Engineering of Glycinebetaine Production toward Enhancing Stress Tolerance in Plants: Metabolic LimitationsPlant Physiology, 2000
- Drought and salt tolerance: towards understanding and applicationTrends in Biotechnology, 1990
- Nutrient requirements of suspension cultures of soybean root cellsExperimental Cell Research, 1968
- A Revised Medium for Rapid Growth and Bio Assays with Tobacco Tissue CulturesPhysiologia Plantarum, 1962