Manipulation of sucrose phloem and embryo loading affects pea leaf metabolism, carbon and nitrogen partitioning to sinks as well as seed storage pools
| Autor: | Mechthild Tegeder, Ming-Zhu Lu, Rachel Snyder, J. E. Grant |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine Sucrose Nitrogen Nitrogen assimilation Plant Science Phloem Photosynthesis 01 natural sciences Pisum 03 medical and health sciences chemistry.chemical_compound Gene Expression Regulation Plant Genetics Nitrogen cycle Plant Proteins biology fungi Peas food and beverages Cell Biology Metabolism Plants Genetically Modified biology.organism_classification Carbon Horticulture 030104 developmental biology chemistry Seeds Desiccation 010606 plant biology & botany |
| Zdroj: | The Plant Journal. 101:217-236 |
| ISSN: | 1365-313X 0960-7412 |
| Popis: | Seed development largely depends on the long-distance transport of sucrose from photosynthetically active source leaves to seed sinks. This source-to-sink carbon allocation occurs in the phloem and requires the loading of sucrose into the leaf phloem and, at the sink end, its import into the growing embryo. Both tasks are achieved through the function of SUT sucrose transporters. In this study, we used vegetable peas (Pisum sativum L.), harvested for human consumption as immature seeds, as our model crop and simultaneously overexpressed the endogenous SUT1 transporter in the leaf phloem and in cotyledon epidermal cells where import into the embryo occurs. Using this 'Push-and-Pull' approach, the transgenic SUT1 plants displayed increased sucrose phloem loading and carbon movement from source to sink causing higher sucrose levels in developing pea seeds. The enhanced sucrose partitioning further led to improved photosynthesis rates, increased leaf nitrogen assimilation, and enhanced source-to-sink transport of amino acids. Embryo loading with amino acids was also increased in SUT1-overexpressors resulting in higher protein levels in immature seeds. Further, transgenic plants grown until desiccation produced more seed protein and starch, as well as higher seed yields than the wild-type plants. Together, the results demonstrate that the SUT1-overexpressing plants with enhanced sucrose allocation to sinks adjust leaf carbon and nitrogen metabolism, and amino acid partitioning in order to accommodate the increased assimilate demand of growing seeds. We further provide evidence that the combined Push-and-Pull approach for enhancing carbon transport is a successful strategy for improving seed yields and nutritional quality in legumes. |
| Databáze: | OpenAIRE |
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