August 23, 2012
Rice Gene Allows Crop To Thrive In Nutrient Deficient Soil
Brett Smith for redOrbit.com - Your Universe Online
In a discovery that could have major implications for the worldwide food supply, scientists at the International Rice Research Institute (IRRI) in the Philippines have identified and leveraged a gene that allows rice to thrive in nutrient deficient soil.
According to their report published this week in the journal Nature, the researchers were able to improve test yields of rice planted in the Philippines, Japan, and Indonesia by 20 percent.
"We found a gene that enhances phosphorus uptake in low phosphorus conditions. We have been looking for it for many years," said lead author Sigrid Heuer.
The gene, phosphorus-starvation tolerance 1 (PSTOL1), was first identified in the Kasalath rice variety that is native to India and grows well in soils low in phosphorus. About a decade ago, scientists identified one or more genes in the plant that allowed it to grow successfully in these scarce conditions. Because of the complexity of the genetic mechanism that imparts this unique ability to the Kasalath plants, it took the IRRI team three years to identify the specific gene responsible.
Heuer and his team were able to isolate and breed the gene through cross-pollination, an important distinction for those against using genetic engineering techniques on food products. Advocates of genetic technology say using traditional pollination techniques can translate into years or even decades of testing before a new strain reaches the market.
The PSTOL-1 gene enables developing rice plants by maximizing their roots´ extraction of phosphorus from the soil. Successful breeding to the gene would reduce the dependence on phosphorus-rich fertilizer in poorer sections of Asia that are known to have nutrient deficient soil.
Because many plant roots are only able to extract a tiny amount of phosphorus from the soil, farmers around the world spread phosphorus-based fertilizer on their fields. In poorer countries, this solution is often too costly, resulting in less than optimal yields when the plants mature. In wealthier countries, more robust rice plants would need less fertilizer, meaning lower costs and less damaging phosphate runoff into the water table.
"Fifty percent of world's arable land is too low in phosphorus. It's not like if you have this gene that the plants don't need phosphorus anymore," Heuer told Tan Ee Lyn of Reuters.
"They (rice plants with the gene) may be able to exploit the soil a little better so the harvest is better. They may make better use of fertilizer because they can take it up more efficiently ... If you have a bigger root system, then the plant can take it up better and they can have better access to the patches where the phosphorus is."
Because the unique ability was found in a plant that thrives in less arable conditions in eastern India, this latest study underlines the importance of biodiversity and conservation. If the Kasalath plant were wiped out by the destruction of habitat–the PSTOL-1 gene may have never been identified.
The group plans to share the results of their work with other scientists around the world that are researching more robust and tolerant strains of crops. They expect the PSTOL1-enhanced rice plants to reach the market within the next 5 years.