Root Traits For Wheat Drought Stress Tolerance

Background

Multiseriate cortical sclerenchyma (MCS) are characterized by small outer root cortical cells with thick cell walls. We recently discovered and characterized this novel root trait and demonstrated its utility for enhanced root penetration of maize and wheat in hard soils. MCS cells walls are highly lignified which enables penetration of hard soils through enhanced cortical tensile strength and bending force of the root tip. In addition to compaction tolerance, MCS may also have utility in drought environments. Under drought stress in the field, maize genotypes with MCS were more resistant to drought than genotypes without MCS. Greater root tensile strength may enable the penetration of hard, dry soils. Increased lignification of cortical cells reduces root radial hydraulic conductivity that may promote soil water conservation throughout the growth season, a strategy known as “water banking”.  Genetic variation is present for MCS and heritability is relatively high, suggesting that this trait could be successfully selected in breeding programs using either phenotypic or marker-assisted selection.

Project description

We observed intraspecific variation in MCS in several Poaceae species including maize, barley, and wheat. Wheat and barley exhibit a strong MCS phenotype with many more outer cortical cell files lignified with much thicker cell walls compared to maize. Therefore, we expect the MCS phenotype to have significantly greater utility for drought stress tolerance in wheat when compared to maize. In collaboration with CIMMYT Mexico and Penn State University we will sample root anatomy in diverse wheat lines and phenotype for MCS. We will also identify important molecular markers for this trait in wheat.