Plate Nº 69 · recorded November 11, 2026
Biology & EvolutionReported finding
Maize gene linked to 60% higher grain nickel in 1,404 accessions
Researchers traced more than 50 years of mystery to ZmNAET1, a maize gene tied to 60% higher grain nickel, smaller grains and weaker seed germination.
By Nathan Brooks4 min read714 words
In brief
- A 2026 Cell study identified ZmNAET1 as a key transporter involved in maize nickel movement.
- The genome-wide association study examined 1,404 maize accessions.
- Accessions with higher ZmNAET1 expression had about 60% more nickel in their grain.
- Mutant seeds stored for eight months to one year had markedly reduced germination; nickel restored it, while zinc did not.
- Two rice genes, OsNAET1 and OsNAET2, also help determine grain nickel content.
By Nathan Brooks
A maize gene called ZmNAET1 is associated with about 60% more nickel in grain, based on a study of 1,404 accessions published in Cell in 2026. The same work links impaired ZmNAET1 function to lower ear weight, smaller grains, less starch and reduced germination after storage.
Chao Daiyin led the study at the Center for Excellence in Molecular Plant Sciences of the Chinese Academy of Sciences. Yan Jianbing’s team at Huazhong Agricultural University collaborated on the research.
What problem did the study solve?
Nickel has an important physiological role in plants, but its route from stems and leaves into grain remained poorly understood for more than 50 years. The researchers call their study the “first to identify genes controlling long-distance nickel transport in grasses.”
The study proposes a genetic control point for that source-to-sink transport, meaning movement from nutrient-supplying tissues into tissues that store or use nutrients. It also links nickel delivery with nitrogen metabolism, seed vigor and yield formation through urease, an enzyme that helps break down urea.
How did researchers find ZmNAET1?
Justus von Liebig, a founder of plant nutrition, proposed the “law of the minimum” in 1840. The principle says crop growth depends on the nutrient in shortest supply, including micronutrients such as nickel.
The team located ZmNAET1 through a genome-wide association study, a method that links DNA differences to measured traits. They examined 1,404 maize accessions collected across multiple years and locations.
Natural variation in the gene’s regulatory region affected grain nickel content. Accessions with higher ZmNAET1 expression had roughly 60% higher nickel concentrations, a difference that could guide breeding.
How does the transporter move nickel?
Molecular, cell-biological and biochemical tests placed ZmNAET1 mainly in phloem cells at stem nodes and ear shanks. Phloem cells transport sugars and dissolved materials through the plant.
Within those cells, the protein exports NA synthesized on site. NA is nicotianamine, a plant-specific, nonprotein amino acid that acts as a free molecule rather than a protein component.
Outside the cells, NA binds free nickel to form Ni–NA complexes. Other transporters carry those complexes back into the phloem, which delivers them to sink organs such as grains.
What happens when ZmNAET1 fails?
Impairing ZmNAET1 function changed several grain traits:
- Substantially lower grain nickel.
- Lower ear weight and smaller grain size.
- Reduced starch content.
- Lower germination rates after storage.
Mutant seeds stored for eight months to one year showed markedly reduced germination. Under those experimental conditions, nickel supplementation restored germination, whereas zinc supplementation did not.
Foliar nickel, meaning nickel sprayed onto leaves, also restored plant height and urease activity in field-treated plants. Both measures had fallen when gene function was impaired.
Disrupted transport lowered urease activity in grains and other sink organs. That reduced urea utilization and, in turn, affected amino acid synthesis and energy metabolism.
Does the mechanism extend to rice and other cereals?
The researchers identified two homologous genes in rice, OsNAET1 and OsNAET2. Both help determine grain nickel content, indicating that the mechanism is conserved across cereal crops.
Related genes in the model plant Arabidopsis thaliana primarily regulate iron, copper and cobalt transport. In maize and rice, NAET1 mainly affects nickel distribution and, to a lesser extent, zinc.
The difference points to distinct long-distance metal transport strategies between grasses and dicotyledonous plants. These are the two major groups of flowering plants.
What could the finding change?
Grasses have long been considered to have low nickel requirements and rarely show deficiency signs. The new mechanism calls that conventional view into question.
The study also reveals a previously unrecognized role for NA in allocating nickel to sink organs. That process operates independently of the known mugineic acid pathway.
Together, the results fill a longstanding gap in source-to-sink nickel transport. They support reassessing the idea that grasses need little nickel and rarely experience deficiency.
The researchers said the findings could improve cereal yield and seed vigor through nutrient management and molecular breeding, which selects useful DNA variants. The work identifies a breeding target, rather than demonstrating an immediate commercial yield gain.
Cell published the paper as “Nicotianamine-driven Nickel Transport to Sink Organs Underpins Maize Productivity” in 2026. Its DOI is 10.1016/j.cell.2026.10.035.
via phys.org/rss-feed/ (Source)
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