Genetic Control of Plasticity in Root Morphology and Anatomy of Rice in Response to Water Deficit
Elucidating the genetic control of rooting behavior under water-deficit stress is essential to breed climate-robust rice (Oryza sativa) cultivars. Using a diverse panel of 274 indica genotypes grown under control and water-deficit conditions during vegetative growth, we phenotyped 35 traits, mostly related to root morphology and anatomy, involving 45,000 root-scanning images and nearly 25,000 cross sections from the root-shoot junction. The phenotypic plasticity of these traits was quantified as the relative change in trait value under water-deficit compared with control conditions. We then carried out a genome-wide association analysis on these traits and their plasticity, using 45,608 high-quality single-nucleotide polymorphisms. One hundred four significant loci were detected for these traits under control conditions, 106 were detected under water-deficit stress, and 76 were detected for trait plasticity. We predicted 296 (control), 284 (water-deficit stress), and 233 (plasticity) a priori candidate genes within linkage disequilibrium blocks for these loci. We identified key a priori candidate genes regulating root growth and
development and relevant alleles that, upon validation, can help improve rice adaptation to water-deficit stress.
Niteen N. Kadam, Anandhan Tamilselvan, Lovely M.F. Lawas, Cherryl Quinones, Rajeev N. Bahuguna, Michael J. Thomson, Michael Dingkuhn, Raveendran Muthurajan, Paul C. Struik, Xinyou Yin, S.V. Krishna Jagadish (2017) Plant Physiology 174 (4): 2302 - 2315
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