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.



[journal.frontiersin.org]