論文 - 詳細
| RRC ID | 49501 |
|---|---|
| 著者 | Takayama M, Matsukura C, Ariizumi T, Ezura H. |
| タイトル | Activating glutamate decarboxylase activity by removing the autoinhibitory domain leads to hyper γ-aminobutyric acid (GABA) accumulation in tomato fruit. |
| ジャーナル | Plant Cell Rep |
| Abstract |
KEY MESSAGE:The C-terminal extension region of SlGAD3 is likely involved in autoinhibition, and removing this domain increases GABA levels in tomato fruits. γ-Aminobutyric acid (GABA) is a ubiquitous non-protein amino acid with several health-promoting benefits. In many plants including tomato, GABA is synthesized via decarboxylation of glutamate in a reaction catalyzed by glutamate decarboxylase (GAD), which generally contains a C-terminal autoinhibitory domain. We previously generated transgenic tomato plants in which tomato GAD3 (SlGAD3) was expressed using the 35S promoter/NOS terminator expression cassette (35S-SlGAD3-NOS), yielding a four- to fivefold increase in GABA levels in red-ripe fruits compared to the control. In this study, to further increase GABA accumulation in tomato fruits, we expressed SlGAD3 with (SlGAD3 OX ) or without (SlGAD3ΔC OX ) a putative autoinhibitory domain in tomato using the fruit ripening-specific E8 promoter and the Arabidopsis heat shock protein 18.2 (HSP) terminator. Although the GABA levels in SlGAD3 OX fruits were equivalent to those in 35S-SlGAD3-NOS fruits, GABA levels in SlGAD3ΔC OX fruits increased by 11- to 18-fold compared to control plants, indicating that removing the autoinhibitory domain increases GABA biosynthesis activity. Furthermore, the increased GABA levels were accompanied by a drastic reduction in glutamate and aspartate levels, indicating that enhanced GABA biosynthesis affects amino acid metabolism in ripe-fruits. Moreover, SlGAD3ΔC OX fruits exhibited an orange-ripe phenotype, which was associated with reduced levels of both carotenoid and mRNA transcripts of ethylene-responsive carotenogenic genes, suggesting that over activation of GAD influences ethylene sensitivity. Our strategy utilizing the E8 promoter and HSP terminator expression cassette, together with SlGAD3 C-terminal deletion, would facilitate the production of tomato fruits with increased GABA levels. |
| 巻・号 | 36(1) |
| ページ | 103-116 |
| 公開日 | 2017-1-1 |
| DOI | 10.1007/s00299-016-2061-4 |
| PII | 10.1007/s00299-016-2061-4 |
| PMID | 27704232 |
| MeSH | Amino Acid Sequence Amino Acids / metabolism Biosynthetic Pathways / genetics Carotenoids / biosynthesis Enzyme Activation Ethylenes / metabolism Fruit / enzymology* Gene Expression Regulation, Plant Genes, Plant Glutamate Decarboxylase / chemistry* Glutamate Decarboxylase / genetics Glutamate Decarboxylase / metabolism* Pigmentation / genetics Plants, Genetically Modified Protein Domains RNA, Messenger / genetics RNA, Messenger / metabolism Sequence Alignment Sequence Deletion* Solanum lycopersicum / enzymology* Solanum lycopersicum / genetics gamma-Aminobutyric Acid / metabolism* |
| IF | 3.825 |
| 引用数 | 16 |
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| 最多言及媒体 | X(Twitter) |
| 各媒体での言及数の合計 | 18 |
| 過去6か月間でのオルトメトリクス指標の変動値 | 0.0 |
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