Plant growth, productivity, and seed yield depend on the efficient uptake, metabolism, and allocation of nutrients. Nitrogen is an essential macronutrient needed in high amounts. Plants have evolved efficient and sele...Plant growth, productivity, and seed yield depend on the efficient uptake, metabolism, and allocation of nutrients. Nitrogen is an essential macronutrient needed in high amounts. Plants have evolved efficient and selective transport systems for nitrogen uptake and transport within the plant to sustain development, growth, and finally reproduction. This review summarizes current knowledge on membrane proteins involved in transport of amino acids and peptides. A special emphasis was put on their function in planta. We focus on uptake of the organic nitrogen by the root, source-sink partitioning, and import into floral tissues and seeds.展开更多
Metabolite transport processes and primary metabolism are highly interconnected. This study exam- ined the importance of source-to-sink nitrogen partition- ing, and associated nitrogen metabolism for carbon capture, t...Metabolite transport processes and primary metabolism are highly interconnected. This study exam- ined the importance of source-to-sink nitrogen partition- ing, and associated nitrogen metabolism for carbon capture, transport and usage. Specifically, Arabidopsis aap8 （AMINO ACID PERMEASE 8） mutant lines were analyzed to resolve the consequences of reduced amino acid phloem loading for source leaf carbon metabolism, sucrose phloem transport and sink development during vegetative and reproductive growth phase. Results showed that decreased amino acid transport had a negative effect on sink development of aap8 lines throughout the life cycle, leading to an overall decrease in plant biomass. During vegetative stage, photosynthe- sis and carbohydrate levels were decreased in aap8 leaves, while expression of carbon metabolism and transport genes, as well as sucrose phloem transport were not affected despite reduced sink strength. However, when aap8 plants transitioned to reproductive phase, carbon fixation and assimilation as well as sucrose partitioning to siliques were strongly decreased. Overall, this work demonstrates that phloem loading of nitrogen has varying implications for carbon fixation, assimilation and source-to-sink allocation depending on plant growth stage. It further suggests alterations in source-sink relationships, and regulation of carbon metabolism and transport by sink strength in a development-dependent manner.展开更多
基金Research in M.T.＇s laboratory was supported by the US National Science Foundation （IOS 0135344 and IOS 0448506） and by the Agricultural and Food Research Initiative Competitive Grant no. 2010-65115-20382 from the USDA National Institute of Food and Agriculture. Work in D.R.＇s laboratory was supported by grants from the Swiss National Science Foundation 3100A0-107507 and 31003A 127340, and EU Marie Curie Research Training Network ＇VaTEP - Vacuolar Transport Equipment for Growth Regulation of Plants＇ （M RTN-CT-2006-035833）. No conflict of interest declared.
文摘Plant growth, productivity, and seed yield depend on the efficient uptake, metabolism, and allocation of nutrients. Nitrogen is an essential macronutrient needed in high amounts. Plants have evolved efficient and selective transport systems for nitrogen uptake and transport within the plant to sustain development, growth, and finally reproduction. This review summarizes current knowledge on membrane proteins involved in transport of amino acids and peptides. A special emphasis was put on their function in planta. We focus on uptake of the organic nitrogen by the root, source-sink partitioning, and import into floral tissues and seeds.
基金supported by the U.S. National Science Foundation grant number IOS 1021286 and IOS 1457183
文摘Metabolite transport processes and primary metabolism are highly interconnected. This study exam- ined the importance of source-to-sink nitrogen partition- ing, and associated nitrogen metabolism for carbon capture, transport and usage. Specifically, Arabidopsis aap8 （AMINO ACID PERMEASE 8） mutant lines were analyzed to resolve the consequences of reduced amino acid phloem loading for source leaf carbon metabolism, sucrose phloem transport and sink development during vegetative and reproductive growth phase. Results showed that decreased amino acid transport had a negative effect on sink development of aap8 lines throughout the life cycle, leading to an overall decrease in plant biomass. During vegetative stage, photosynthe- sis and carbohydrate levels were decreased in aap8 leaves, while expression of carbon metabolism and transport genes, as well as sucrose phloem transport were not affected despite reduced sink strength. However, when aap8 plants transitioned to reproductive phase, carbon fixation and assimilation as well as sucrose partitioning to siliques were strongly decreased. Overall, this work demonstrates that phloem loading of nitrogen has varying implications for carbon fixation, assimilation and source-to-sink allocation depending on plant growth stage. It further suggests alterations in source-sink relationships, and regulation of carbon metabolism and transport by sink strength in a development-dependent manner.
