Genetic manipulation of the γ-aminobutyric acid (GABA) shunt in rice: overexpression of truncated glutamate decarboxylase (GAD2) and knockdown of γ-aminobutyric acid transaminase (GABA-T) lead to sustained and high levels of GABA accumulation in rice kern
| Autor: | Kumiko Kainou, Kazuhito Akama, Yasuka Shimajiri, Takayuki Oonishi, Kae Ozaki |
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| Rok vydání: | 2013 |
| Předmět: |
DNA
Bacterial Transgene Blotting Western Genetic Vectors Glutamate decarboxylase Carboxylic Acids Plant Science Aminobutyric acid Transaminase GAD2 Transformation Genetic Glutelin Transgenes Amino Acids Crosses Genetic gamma-Aminobutyric Acid Plant Proteins chemistry.chemical_classification biology Glutamate Decarboxylase Catabolism food and beverages Oryza Starch Plants Genetically Modified Amino acid Blotting Southern nervous system Biochemistry chemistry 4-Aminobutyrate Transaminase Gene Knockdown Techniques Seeds biology.protein Amylose Agronomy and Crop Science Biotechnology |
| Zdroj: | Plant Biotechnology Journal. 11:594-604 |
| ISSN: | 1467-7644 |
| DOI: | 10.1111/pbi.12050 |
| Popis: | Gamma-aminobutyric acid (GABA) is a non-protein amino acid commonly present in all organisms. Because cellular levels of GABA in plants are mainly regulated by synthesis (glutamate decarboxylase, GAD) and catabolism (GABA-transaminase, GABA-T), we attempted seed-specific manipulation of the GABA shunt to achieve stable GABA accumulation in rice. A truncated GAD2 sequence, one of five GAD genes, controlled by the glutelin (GluB-1) or rice embryo globulin promoters (REG) and GABA-T-based trigger sequences in RNA interference (RNAi) cassettes controlled by one of these promoters as well, was introduced into rice (cv. Koshihikari) to establish stable transgenic lines under herbicide selection using pyriminobac. T₁ and T₂ generations of rice lines displayed high GABA concentrations (2-100 mg/100 g grain). In analyses of two selected lines from the T₃ generation, there was a strong correlation between GABA level and the expression of truncated GAD2, whereas the inhibitory effect of GABA-T expression was relatively weak. In these two lines both with two T-DNA copies, their starch, amylose, and protein levels were slightly lower than non-transformed cv. Koshihikari. Free amino acid analysis of mature kernels of these lines demonstrated elevated levels of GABA (75-350 mg/100 g polished rice) and also high levels of several amino acids, such as Ala, Ser, and Val. Because these lines of seeds could sustain their GABA content after harvest (up to 6 months), the strategy in this study could lead to the accumulation GABA and for these to be sustained in the edible parts. |
| Databáze: | OpenAIRE |
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