Published on March 23rd, 2013 | by James Ayre0
Corn That Is Tolerant Of Toxic Soils Moving Closer To Reality, Gene In Triplicate Provides The Resistance
Corn crops capable of being grown in toxic soils are moving closer to reality, new research from the U.S. Department of Agriculture and Cornell University is suggesting. The new research has been attempting to unravel the reasons for why some maize plants can tolerate toxic aluminum in soil, and some can’t.
Interestingly, the research found that it was the presence of a specific gene in triplicate, only when there were three of the gene did it provide the necessary resistance.
“Aluminum toxicity comes close to rivaling drought as a food-security threat in critical tropical food-producing regions.”
“Acidic soils dissolve aluminum from clays in the soil, 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, which binds to and locks up aluminum, thereby preventing it from harming roots.”
“We found three functional copies that were identical,” stated senior author Leon Kochian, director of the U.S. Department of Agriculture — Agriculture Research Service Plant, Soil and Nutrition Laboratory at Cornell. “This is one of the first examples of copy number variation contributing to an agronomically important trait.”
The extra gene copies appear to have cumulative effect, coding more of the protein “that transports aluminum-binding citric acid into the soil.”
“This could be a key factor for other traits of agricultural importance,” said Kochian.
“Copy number variation is well documented in the human genome,” Kochian said, “and maize does a lot of this, so there are probably many examples.”
There are always unintended side effects when you select for certain traits in an organism though, so it remains to be seen if this specific finding will end up being agriculturally valuable. If you select for fast growth you limit nutrients, if you select for drought hardiness you make it more susceptible to water damage, if you select for early harvest you may decrease disease resistance, etc.
Image Credit: Cornell University.