In a lab already distinguished for excellence, yet another great discovery has been made. At the United States Plant, Soil and Nutrition Laboratory, scientists have been able to isolate and clone an aluminum-resistant gene in sorghum plants that allows them to grow in acidic soil, the same acidic soil that covers over half of the world with a heavy concentration in under-developed countries in Africa, Asia and South America.
Leon Kochian, the research leader and supervisory plant physiologist at the United States Plant, Soil and Nutrition Laboratory USDA-ARS and a Cornell adjunct professor in plant mineral nutrition, has been working on isolating this gene for over ten years. According to Kochian, over that time, “a lot of breeding has been done to isolate this gene.”
The aluminum-tolerant gene encodes a transport membrane protein residing in the nuclear membrane of the root tip where cell division and expansion occur. The expression of this gene is triggered by the presence of aluminum in the soil. These proteins transport citric acid outside of the root tip, which in turn binds with the toxic aluminum in the soil and renders it inert.
The laboratory, located near the Veterinary School, focuses primarily on problems with American agriculture, but its close relationship with the Brazilian Agriculture Research Corporation, known as Embrapa, has provided the means for practical research and application of this new aluminum resistant gene. Embrapa’s mission is to “provide feasible solutions for sustainable development of Brazilian Agribusiness through knowledge and technology generation and transfer,” according to its website.
Kochian explained that his principle connection with Embrapa is through Jurandir Magalhaes, a colleague in agricultural research.
"Dr. Magalhaes came to my lab from Embrapa, which is the Brazilian national agricultural research agency, for his Ph.D in the department of crop and soil sciences,” Kochian said. “He came to work on sorghum aluminum tolerance and brought with him a number of excellent genetic resources in sorghum, such as mapping populations and near isogenic lines. Using these materials, he first showed that a single gene controlled most of the variation in aluminum tolerance in sorghum."
Kochian and Jurandir were able to identify this gene and clone it using mapped base cloning.
Sorghum originated in Africa and now ranks as the fifth most important cereal crop in the world. The plant is naturally resistant to heat and is a staple of agriculture in many developing countries. Researchers are now focused on getting aluminum-resistant sorghum out into the field, because ultimately, “this has to go to the field and work.” However, the task is made more difficult because much of the world is still skeptical of genetically modified organisms, or GMOs.
Ideally, this aluminum-resistant sorghum will allow farmers in underdeveloped countries to begin to improve their yield. Kochian notes that in order to be truly efficient, “the goal would be to improve yields for the poor African farmers. The hope would be to increase yields to the level where the farmers are self-sufficient and can also derive some income from their crop. This can then be used to purchase a bit of fertilizer and other soil amendments to begin to improve the soil, and also more seed of the improved variety, which in turn would increase yields further. One can envisage this as a positive cycle that feeds upon itself to improve the lives of farmers."
Moreover, this new aluminum-resistant gene is not limited to sorghum plants. As Kochian explained, “once you make a breakthrough like this, it can be found in other species like corn and barley that use a similar gene related to aluminum tolerance.”