Dissertation
Improving plant performance and nitrogen use efficiency by altering amino acid transport processes
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/111558
Abstract
Nitrogen (N) is an essential nutrient for plant growth and development. Plants take up inorganic (i.e. ammonium and nitrate) as well as organic (i.e. amino acids and peptides) N from the soil. Within the plant, long-distance transport of N generally occurs in the form of amino acids. Both amino acid uptake into roots and partitioning from source to sink requires plasma-membrane localized transport proteins. This research addresses the role of transporters in amino acid uptake and distribution within the plant, and their importance for efficient N use for plant metabolism and productivity.
First, the function of Arabidopsis lysine-histidine-like transporter (LHT6) and amino acid permease (AAP1) in root N import was examined. Growth and uptake studies were performed with a range of amino acids or their toxic analogues using lht6 and aap1 mutants as well as the lht6/aap1 cross. The results demonstrated that both LHT6 and AAP1 are involved in root acquisition of acidic and neutral amino acids at ecologically relevant concentrations.
Further, transporter function in source-to-sink N partitioning and their importance for N use efficiency were analyzed using pea plants overexpressing an amino acid transporter (AAP1) in the leaf phloem and in seeds. Plants were grown in low, moderate and high N environments and results showed increases in seed yield and N use efficiency under all N conditions.
Finally, the importance of regulated N partitioning to leaves for photosynthesis and N use efficiency was investigated. Arabidopsis aap2 mutants that allocate more amino acids to leaves than control plants were analyzed in a range of N environments. Results showed that no matter the N condition, C fixation and allocation to seed sinks were improved in the aap2 plants. The mutants displayed improved photosynthetic and overall plant N use efficiency, independent of the N supply.
Taken together this graduate work demonstrates that (1) amino acid transport controls N acquisition and partitioning within the plant, (2) transporter function influences plant performance, seed yield and efficient use of N, and (3) altering amino acid allocation in plants can provide strategies to obtain high plant yields, while reducing N fertilizer inputs.
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Details
- Title
- Improving plant performance and nitrogen use efficiency by altering amino acid transport processes
- Creators
- Molly Perchlik
- Contributors
- Mechthild Tegeder (Advisor)Asaph B Cousins (Committee Member)David R Gang (Committee Member)Thomas B Jobson (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Biological Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 213
- Identifiers
- 99900581824501842
- Language
- English
- Resource Type
- Dissertation