Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions

Abstract

The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas. 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.

Genotypic variation in soil water use and root distribution and their implications for drought tolerance in chickpea

“…Recent studies on the importance of size of roots to grain yields and the timing of soil water utilisation for maximising grain yields under terminal DS had drawn variable conclusions such as positive (Sponchiado et al 1989;White and Castillo 1992;Eghball and Maranville 1993;Kramer and Boyer 1995;Lynch 1995Lynch , 2013Pandey et al 2000aPandey et al , 2000bLiao et al 2004;Nord and Lynch 2009;Puangbut et al 2009;Lopes and Reynolds 2010;Manschadi et al 2010;Zhu et al 2010;Franco et al 2011;Kell 2011;Trachsel et al 2011;Suji et al 2012;Wasson et al 2012Wasson et al , 2014Comas et al 2013;Jaramillo et al 2013;Uga et al 2013; Root traits contribution to drought tolerance Functional Plant Biology Fenta et al 2014;Chimungu et al 2014aChimungu et al , 2014bLynch et al 2014;Bishopp and Lynch 2015) and negative or null (Ritchie 1981;Dardanelli et al 2004;CIAT 2007CIAT , 2008Beebe et al 2009;Itoh et al 2009;Ma et al 2010;Manavalan et al 2011;Ratnakumar et al 2009;Zaman-Allah et al 2011;Kumar et al 2012;…”

Does Morphological and Anatomical Plasticity during the Vegetative Stage Make Wheat More Tolerant of Water Deficit Stress Than Rice?

“…Contrastingly, a higher root hydraulic conductivity helped to maintain a higher photosynthetic rate (Adachi et al, 2010), with tolerant cultivars maintaining greater root hydraulic conductivity than susceptible cultivars (Matsuo et al, 2009). Furthermore, upland rice cultivars with deeper roots outperformed lowland cultivars possessing a shallow root system when encountered with water deficit stress (Uga et al, 2013). Additionally, majoreffect grain yield metaquantitative trait loci under water deficit stress identified in rice were found to colocalize on the genomes of other dryland cereals such as wheat, maize, and pearl millet (Pennisetum glaucum; Swamy et al, 2011), indicating a possible common evolutionary pathway for water deficit adaptation across cereals.…”

Natural Variation of Root Traits: From Development to Nutrient Uptake

“…Multiple studies for traits related to RSA were also conducted in rice (Oryza sativa). Using RILbased QTL and subsequent near isogenic lines-based fine mapping for a trait for deep rooting in rice, allelic variation of the gene DEEPER ROOTING1 was determined to cause a deep rooting phenotype by affecting the growth angle of roots, which over time, translates into deeper rooting and confers enhanced drought tolerance (Uga et al, 2013). Furthermore, by phenotyping three-dimensional traits of rice RSA, a large number of QTL could be identified in an RIL population (Topp et al, 2013).…”