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.
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We thank K. Shimamoto (NAra Institute of Science and Technology, NAIST) and E.E. Hood (Arkansas State University) for kindly providing the pANDA vector and Agrobacterium (EHA101), respectively. Full-length cDNAs for use as controls in the quantitative RT-PCR experiments were provided by the Rice Genome Resource Center of NIAS. We thank N. Hattori, T. Tanaka, M. Yamanouchi, K. Matsubara, S. Mochizuki, N. Yokotani, T. Mizubayashi, T. Ando, N. Sentoku and A. Tagiri for technical support and advice on molecular analysis; T. Nishikawa, Y. Itai, M. Takimoto, E. Nakao, H. Oode, R. Matsushita and the staff of the technical support section of NIAS for technical assistance during field evaluation; M. Kondo, A. Oyanagi, T. Izawa, E. Yamamoto, T. Hoshino, J. Tohme, C.P. Martinez, N.T. Perea and A. Fernando for valuable discussion; and K. Shinozaki for critical reading of the manuscript. This work was supported by a grant from the Ministry of Agriculture, Forestry and Fisheries of Japan (QTL-4003 and RBS-2009).
The authors declare no competing financial interests.
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Uga, Y., Sugimoto, K., Ogawa, S. et al. Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions. Nat Genet 45, 1097–1102 (2013). https://doi.org/10.1038/ng.2725
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