Nagoya University Discovers Molecular Shoot-to-root Signal System in Nitrogen-starved Plants

Scientists at Nagoya University revealed the molecular mechanisms that occur during nitrogen starvation in plants. The results are published in Nature Plants.

Nitrogen is vital for plant growth, but it is present as patches in the soil. When plants are lacking with nitrogen, the roots express a mobile plant hormone (CEP) which travels to the shoot and then signals compensatory nitrogen uptake by the roots from soil areas with high concentration of nitrogen. The signal from CEP is received by a protein present in the leaves, but the molecules working on the shoot-to-root reaction were unidentified.

Nagoya University researchers elucidated that phloem-specific polypeptides are turned on after receiving CEP signal, leading to the expression of nitrate transporter gene when nitrate is present in the soil around the root. They found out that these polypeptides build up in the roots, however the genes that code for them were expressed only in the shoots. Thus, the polypeptides act as mobile descending shoot-to-root signals. This complex signaling system implies that plants have efficient mechanisms to ensure optimal nutrient intake. The information provided by the study can be used to enhance fertilizer usage and improve plant productivity.

For more details, read the press release from Nagoya University and the research article in Nature Plants.