state in the abstract:
The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas1. Here we demonstrate that alteration of root system architecture improves drought avoidance through the cloning and characterization of DEEPER ROOTING 1 (DRO1), a rice quantitative trait locus controlling root growth angle. DRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity. Higher expression of DRO1 increases the root growth angle, whereby roots grow in a more downward direction. Introducing DRO1 into a shallow-rooting rice cultivar by backcrossing enabled the resulting line to avoid drought by increasing deep rooting, which maintained high yield performance under drought conditions relative to the recipient cultivar. Our experiments suggest that control of root system architecture will contribute to drought avoidance in crops.Asian Scientist contascted team lead Yusaku Uga and got more insight into the new cultivar:
A gene that gives rice plants deeper roots can triple yields during droughts, according to Japanese researchers writing in Nature Genetics this week (4 August).Using conventional breeding, the team varieties to get the DRO1 gene expressed in a new cultivar. By using traditional breeding techniques, as the Australian team that developed a new drought tolerant wheat cultivar, researchers ensure the quickest, broadest acceptance of the new variety among growers. And that growers are able to save seed.
Rice is a staple food for nearly half of the world’s population, but is also particularly susceptible to drought owing to its shallow roots, researchers say.
The new study shows that by pointing roots down instead of sideways, the Deeper Rooting 1 (DRO1) gene results in roots that are nearly twice as deep as those of standard rice varieties.
“If rice adapts to or avoids drought conditions using deeper roots, it can get water and nutrients from the deep soil layers,” says the study’s lead author Yusaku Uga, a researcher with Japan’s National Institute of Agrobiological Sciences.Uga and his team found that in moderate drought conditions, the yield of rice with DRO1 was double that of the shallow-rooted rice variety. Under severe drought conditions, this increased to 3.6 times greater.
“The most important point is that we had rice grains produced under drought conditions,” says Uga.