While the debate over state bans or labeling of genetically engineered grows hotter by the day, it hasn't slowed ag researchers from discovering and splicing genes together for exciting new uses. We recently told you about the corn "Scarecrow" gene trait discovered by Cornell University researchers.
Last week, another new maize trait was announced by a USDA/Cornell research team. The team at Cornell's Boyce Thompson Institute for Plant Research found three genes in the maize (corn) genome that increase tolerance to aluminum toxicity in soils.
Aluminum toxicity comes close to rivaling drought as a food-security threat in critical tropical food-producing countries such as Brazil. Three identical functional genes contribute to this agronomically important trait, says Leon Kochian, director of the USDA Ag Research Service lab at Cornell. What's more, the extra gene copies had a cumulative effect of coding for more protein that transports aluminum-binding citric acid into the soil.
How it works
Acidic soils dissolve aluminum from clays in tropical soils, making it toxic to plant roots in half the world's arable lands. The MATE1 gene, which was found in triplicate in aluminum-tolerant maize, turns on in the presence of aluminum ions and expresses a protein that transports citric acid from root tips into the soil. In turn, it binds to and locks up aluminum, preventing it from harming roots.
The finding points to the importance of looking for multiple copies of a gene for higher expression of certain traits. "This could be a key factor for other traits of agricultural importance," adds Kochian.
"[Gene] copy number variation is well documented in the human genome," notes Kochian, "and maize does a lot of this, so there are probably many examples."
The research came out of a long collaboration on aluminum tolerance in Brazil. Cornell researchers worked with others at the University of Florida, University of Missouri, Arizona Genomics Institute and New York's Cold Spring Harbor Laboratory.