Engineering α-amylase levels in wheat grain suggests a highly sophisticated level of carbohydrate regulation during development
| Autor: | Hanna M Robinson, Phililp J Larkin, Jean-Philippe Ral, Matthew K. Morell, Crispin A. Howitt, Jos C. Mieog, Michelle L. Colgrave, Keren Byrne, Alex Whan, Anne-Sophie Dielen, Andrew F. Bowerman |
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| Rok vydání: | 2014 |
| Předmět: |
Gene isoform
Sucrose Physiology Starch Plant Science Biology oil Endosperm chemistry.chemical_compound Gene Expression Regulation Plant wheat endosperm Triglycerides Triticum Plant Proteins AMY3 chemistry.chemical_classification starch food and beverages sucrose Carbohydrate Enzyme chemistry Biochemistry Germination Carbohydrate Metabolism Composition (visual arts) alpha-Amylases Research Paper |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 |
| Popis: | Summary Endosperm-specific over-expression of wheat α-amylase TaAMY3 during grain development revealed unexpected effects on grain composition, carbon partitioning, fatty acid accumulation, and germination. Wheat starch degradation requires the synergistic action of different amylolytic enzymes. Our spatio-temporal study of wheat α-amylases throughout grain development shows that AMY3 is the most abundant isoform compared with the other known α-amylases. Endosperm-specific over-expression of AMY3 resulted in an increase of total α-amylase activity in harvested grains. Unexpectedly, increased activity did not have a significant impact on starch content or composition but led to an increase of soluble carbohydrate (mainly sucrose) in dry grain. In AMY3 overexpression lines (A3OE), germination was slightly delayed and triacylglycerol (TAG) content was increased in the endosperm of mature grain. Despite increased AMY3 transcript and protein content throughout grain development, alterations of α-amylase activity and starch granule degradation were not detected until grain maturation, suggesting a post-translational inhibition of α-amylase activity in the endosperm during the starch filling period. These findings show unexpected effects of a high level of α-amylase on grain development and composition, notably in carbon partitioning and TAG accumulation, and suggest the presence of a hitherto unknown regulatory pathway during grain filling. |
| Databáze: | OpenAIRE |
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