Functional implications of root cortical senescence for soil resource capture

Root phenes play a primary role in plant adaptation to edaphic stress. Understanding the functional implications of root phenotypes will enable the development of crop varieties with improved soil resource acquisition. Root cortical senescence (RCS) is a type of programmed cell death in cortical cells of several Poaceae species. Until recently there has been very little attention to the functional implications of RCS for water and nutrient capture. We explore the functional implications of RCS as an adaptive trait for water and nutrient acquisition. The present review summarizes evidence from our own studies and other published work, and provides novel insights into the fitness landscape of RCS. Progress has recently been achieved in understanding the development and physiological implications of RCS. We propose that RCS is a useful trait for water and nutrient acquisition, particularly in edaphic stress conditions. Further research is needed to understand the utility and tradeoffs of RCS in the context of specific environments, management practices, and phenotypic backgrounds. The utility of RCS for improved plant performance under edaphic stress merits investigation in the field. RCS may be a useful breeding target for improved soil resource capture in several major crop species including wheat, barley, and triticale.