A wheat/rye polymorphism affects seminal root length and yield across different irrigation regimes.
Howell, T., Moriconi, J. I., Zhao, X., Hegarty, J., Fahima, T., Santa-Maria, G. E. and Dubcovsky, J.
Department of Plant Sciences, University of California, Davis CA, USA.
Instituto Tecnologico Chascomus (IIB-INTECH), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) and Univ. Nacional de San Martin (UNSAM), Chascomus, Buenos Aires,. Argentina.
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel.
Howard Hughes Medical Institute, Chevy Chase, MD. U. S. A.
The introgression of a small segment of wheat (Triticumaestivum L.) chromosome arm 1BS in the distal region of rye (Secalecereale L.) 1RS.1BL arm translocation in wheat (henceforth 1RSRW) was previously associated with reduced grain yield, carbon isotope discrimination and stomatal conductance, suggesting reduced access to soil moisture. Here we show that lines with the normal 1RS arm have longer roots than lines with the 1RSRW arm in both field and hydroponic experiments. In the 1RSRW lines, differences in seminal root length were associated with a developmentally regulated arrest of the root apical meristem (RAM). Approximately 10 days after germination, the seminal roots of the 1RSRW plants showed a gradual reduction in elongation rate, and stopped growing a week later. Seventeen days after germination, the roots of the 1RSRW plants showed altered gradients of reactive oxygen species and emergence of lateral roots close to the RAM, suggesting changes in the root meristem. The 1RSRW lines also showed reduced biomass (estimated by Normalized Differences Vegetation Index) and grain yield relative to the 1RS lines, with larger differences under reduced or excessive irrigation than under normal irrigation. These results suggest that this genetic variation could be useful to modulate root architecture.
J Exp Bot 70(15): 4027-4037 (2019)