Journal article
Altered Xylem-Phloem Transfer of Amino Acids Affects Metabolism and Leads to Increased Seed Yield and Oil Content in Arabidopsis[W]
The Plant cell, Vol.22(11), pp.3603-3620
11/2010
Handle:
https://hdl.handle.net/2376/105066
PMCID: PMC3015121
PMID: 21075769
Abstract
This work examines the amino acid transporter AAP2, which localizes to the phloem throughout the plant and is key for amino acid transfer from the xylem-phloem; mutants in
AAP2
perturb nitrogen-carbon balance in the seed, affect leaf metabolism and development, and increase seed yield and oil content.
Seed development and nitrogen (N) storage depend on delivery of amino acids to seed sinks. For efficient translocation to seeds, amino acids are loaded into the phloem in source leaves and along the long distance transport pathway through xylem-phloem transfer. We demonstrate that
Arabidopsis thaliana
AMINO ACID PERMEASE2 (AAP2) localizes to the phloem throughout the plant.
AAP2
T-DNA insertion lines showed changes in source-sink translocation of amino acids and a decrease in the amount of seed total N and storage proteins, supporting AAP2 function in phloem loading and amino acid distribution to the embryo. Interestingly, in
aap2
seeds, total carbon (C) levels were unchanged, while fatty acid levels were elevated. Moreover, branch and silique numbers per plant and seed yield were strongly increased. This suggests changes in N and C delivery to sinks and subsequent modulations of sink development and seed metabolism. This is supported by tracer experiments, expression studies of genes of N/C transport and metabolism in source and sink, and by phenotypic and metabolite analyses of
aap2
plants. Thus, AAP2 is key for xylem to phloem transfer and sink N and C supply; moreover, modifications of N allocation can positively affect C assimilation and source-sink transport and benefit sink development and oil yield.
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Details
- Title
- Altered Xylem-Phloem Transfer of Amino Acids Affects Metabolism and Leads to Increased Seed Yield and Oil Content in Arabidopsis[W]
- Creators
- Lizhi Zhang - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4236Qiumin Tan - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4236Raymond Lee - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4236Alexander Trethewy - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4236Yong-Hwa Lee - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4236Mechthild Tegeder - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4236
- Publication Details
- The Plant cell, Vol.22(11), pp.3603-3620
- Academic Unit
- Biological Sciences, School of
- Publisher
- American Society of Plant Biologists
- Identifiers
- 99900546782501842
- Language
- English
- Resource Type
- Journal article