Plant Tweak Could Let Toxic Soil Feed Millions:
Scientists at the University of California, Riverside made plants tolerant of poisonous aluminum by tweaking a single gene. This may allow crops to thrive in the 40 to 50 percent of Earth’s soils currently rendered toxic by the metal.“Aluminum toxicity is a very limiting factor, especially in developing countries, in South America and Africa and Indonesia,” said biochemist Paul Larsen. “It’s not like these areas are devoid of plant life, but they’re not crop plants. Among agriculturally important plants, there aren’t mechanisms for aluminum tolerance.”
I’d hate to think that we’d foist genetically modified crops on starving millions…
The plant that Professor Larsen tweaked was not a crop plant though:
He identified a gene in Arabidopsis — a flower used as a model organism in basic plant research — that affects plants’ sensitivity to aluminum. When the gene is modified, seedlings that would normally have died in aluminum-rich soils instead flourished.There’s no guarantee that the tweak will prove successful and safe — but if it does, it could provide food for millions.
Larsen and postdoctoral student Megan Rounds started with an especially aluminum-sensitive Arabidopsis strain, then used a DNA-scrambling mutagen to produce 200,000 seedlings with various mutations. When they scanned the genomes of a few that proved able to grow in aluminum-rich cultures, they found a common factor: a damaged gene called AlATR.
The gene appears to produce an enzyme that — when exposed to aluminum — stops cell division, preventing roots from growing.
“It was always believed that once aluminum got into the tissue” of a non-tolerant species, said Larsen, “it was ‘game over’ for the root. It would accumulate toxic effects, and wouldn’t grow. Here you change one gene, reduce the function of one protein, and all of a sudden you have a plant that can, for the most part, thrive in an aluminum-toxic environment. It was shocking.”
“People have been studying aluminum toxicity for years. People say it binds to the cell wall. Others say it interacts with proteins. Others, that it damages the plasma membrane. Or that it screws up cytoplasmic calcium, or screws up the cytoskeleton, or binds the DNA, or mimics magnesium,” said Leon Kochian, a Cornell University plant physiologist. “This mechanism seems to supersede the others. It renders them immaterial.”