According to a new study from Dartmouth University, researchers have found a gene that regulates the regulation of iron uptake in plants.
With more than 2 billion people worldwide suffering from iron deficiency, the finding could be the secret to rising the iron capacity of crops such as maize, wheat and cassava that make up the staple diets of over half of the world's population.
The gene signals as plants are expected to enable iron to be transported by toggling a genetic process affecting hundreds of other genes. The study, published in the National Academy of Sciences ' Proceedings, is the latest in the Dartmouth team's decades-long series of iron transport and storage research projects in plants. The current research details plant gene identification and provide the first description of how iron uptake is regulated.
"We've found a key regulator on one of the most important nutrient pathways in the world," said Mary Lou Guerinot, a Dartmouth Biological Science Professor and senior project researcher. "If we can now work out how to automate the course, we might feed billions of people suffering from iron deficiency— a major problem especially for women and children around the world." The newly discovered gene, known as the Upstream IRT1 Regulator (URI), regulates which genes should be expressed in the root of a plant to begin iron uptake. URI controls as many as 1,500 other genes, even those with nothing to do with iron, according to the team.
The research team found the URI protein in plants is always present. The protein's constant presence provided the additional challenge of understanding how the protein senses adequate iron status to control itself and prevent toxic overexposure to the component.
"Our research found that iron factors do not affect the concentration of the URI protein," said Sun A Kim, a Dartmouth research scientist and the first author of the paper. "Faced with the finding that the protein is always present, we investigated whether the URI protein is modified to alter its activity in response to the availability of iron."
Researchers found that the URI protein combines with a phosphate molecule under iron-poor conditions and activates a sequence of genetic events to turn the iron absorption system on. This cycle of phosphorylation is a common mechanism that cells use to control the role of proteins and relay signals.
URI also activates a protein that, under iron-sufficient conditions, shuts down the transport of iron through the plant heart.
"We have not only discovered URI, but we also identified DNA regions where the URI protein binds to enable the iron-up pathway to be activated. URI is a transcription factor and is being changed to learn when to bind and turn on other genes," Kim said.
Past research by the team has resulted in crops that accumulate more iron to identify mechanisms that control the transportation and storage of iron in plants. Current research on the model plant Arabidopsis thaliana has been undertaken and provides a key piece to the puzzle of how plants control iron absorption
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