AsianScientist (Aug. 27, 2012) – Scientists have identified a rice gene that boosts crop yields by helping rice plants grow larger roots.
Publishing in the journal Nature, a team of scientists at the International Rice Research Institute (IRRI) based in the Philippines report the discovery of PSTOL1, which stands for Phosphorus Starvation Tolerance 1.
The PSTOL1 protein is a receptor-like cytoplasmic kinase, a family of kinases previously identified in plant responses to drought. PSTOL1 expression causes early root growth and root proliferation. A better root system allows rice plants to access more nutrients such as phosphorus, an important trait in areas with nutrient-poor soil.
Under phosphorus-deficient conditions, the expression of PSTOL1 is enhanced, allowing for better phosphorus absorption and accumulation.
“In field tests in Indonesia and the Philippines, rice with the PSTOL1 gene produced about 20 percent more grain than rice without the gene,” said Dr. Sigrid Heuer, senior scientist at IRRI and leader of the study.
The search began when Dr. Matthias Wissuwa from the Japan International Research Center for Agricultural Sciences discovered a traditional rice variety Kasalath from eastern India that could grow well in phosphorus-poor soil.
Many parts of in Asia have soil deficient in phosphorus. While farmers today use phosphorus fertilizers, this nutrient is often locked in the soil and cannot be absorbed by rice plants.
In addition, not all farmers can afford phosphorus fertilizers, which are expensive. To compound the problem further, phosphorus is a non-renewable resource that is fast running out.
“For many years we have searched for genes that improve phosphorus uptake. We have now hit the jackpot and found PSTOL1, the major gene responsible for improved phosphorus uptake and understand how it works,” said Heuer.
This finding paves the way for rice breeders to produce new rice varieties faster and more easily. Not only does this have the potential to increase global production of rice, the food security and earning power of millions of rice farmers working on nutrient-poor land could be improved.
Interestingly, the team had previously identified additional genomic regions associated with enhanced phosphorus efficiency, which suggests that other genes or regions could similarly amplify the efficiency of nutrient uptake.
It should be noted that rice plants with the PSTOL1 gene are not genetically modified. Instead, they are simply being bred with smart modern breeding techniques.
The PSTOL1 gene is currently being tested in commonly-grown rice varieties and initial results show improved root growth and grain yield. This could lead to enhanced productivity while reducing fertilizer usage and cost to farmers.
The Kasalath rice variety recently made headlines when IRRI research yielded the discovery of the submergence tolerence gene.
These discoveries highlight the need to conserve the genetic diversity of traditional crop varieties. The International Rice Genebank, operated by IRRI, conserves more than 114,000 different types of rice.
The article can be found at: Gamuyao R et al. (2012) The protein kinase Pstol1 from traditional rice confers tolerance of phosphorus deficiency.
Source: IRRI; Photo: IRRI Images/Flickr.
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