Amino Acid Transport Mechanisms in Plants

The uptake, distribution and allocation of amino acids underpin nitrogen transport in plants, influencing growth, development and stress resilience. Amino acid transporters are integral membrane proteins classified into families such as amino acid permeases (AAPs), lysine–histidine‐like transporters (LHTs) and cationic amino acid transporters (CATs), each exhibiting distinct substrate preferences. In photosynthetic source leaves, specific transporters mediate phloem loading to drive long‐distance movement to sinks, including developing seeds and roots. Conversely, roots acquire environmental amino acids via specialised transporters in the epidermis and cortex. Fine regulation of source-to-sink partitioning, underpinned by transporter expression, post-translational modification and interaction with signalling molecules, shapes nitrogen use efficiency and crop yield. Deciphering the molecular mechanisms of amino acid transport offers avenues for enhancing nutritional quality, stress tolerance and sustainable productivity in diverse crops.

Research from Nature Portfolio

Recent work has identified a quantitative trait locus encoding OsAAP6 as a central regulator of grain protein content in rice. Variation in the OsAAP6 promoter correlates with natural diversity in protein accumulation, while overexpression enhances root uptake and redistribution of multiple amino acids into developing grains. These findings provide a molecular framework for manipulating amino acid transport to improve nutritional quality and yield in staple cereals.

Amino Acid Transport Mechanisms in Plants publication trend

The graph below shows the total number of articles in amino acid transport mechanisms in plants across all publications each year (not limited to Nature Index journals).

Technical terms

Amino acid transporter (AAT): A membrane protein that facilitates the movement of amino acids across cellular membranes.

Amino acid permease (AAP): A subfamily of AATs that primarily mediate uptake and distribution of neutral and basic amino acids.

Phloem loading: The active transport of solutes, including amino acids, into the phloem for long-distance transport to sink tissues.

Source and sink: Source organs produce and export photoassimilates, while sink organs import and utilise them for growth and storage.

Reactive oxygen species (ROS): Chemically reactive molecules derived from oxygen that act as signalling agents in stress and developmental responses.

References

1. OsAAP6 functions as an important regulator of grain protein content and nutritional quality in rice. Nature Communications (2014).
2. The amino acid permease SlAAP6 contributes to tomato growth and salt tolerance by mediating branched-chain amino acid transport. Horticulture Research (2024).
3. Types of Membrane Transporters and the Mechanisms of Interaction between Them and Reactive Oxygen Species in Plants. Antioxidants (2024).
4. The Amino Acid Transporter OsAAP4 Contributes to Rice Tillering and Grain Yield by Regulating Neutral Amino Acid Allocation through Two Splicing Variants. Rice (2021).