Soil-root interaction in the rhizosheath regulates the water uptake of wheat

Abstract

The development of crops better adapted to endure weather extremes requires knowledge of the belowground traits that have potential to improve plant water uptake. Recent evidence has indicated that root induced modification of soil pore geometry of the rhizosheath is linked with drought tolerance of crops. Here we sought to understand whether the regulation of plant water uptake by rhizosheath is mediated through the rhizodeposits present at the soil-root interface. We compared eight wheat cultivars and demonstrated that cultivars with longer root hairs and greater rhizosheath mass and cover transpired more water. The wheat cultivars with less rhizosheath had the highest concentration of trehalose in the rhizosheath. Trehalose may increase the surface tension of soil water, which could further modify the transpiration of cultivars with less rhizosheath. Moreover, rhizosheath mass and cover had significant negative association with the bacterial abundance, indicating a link between metabolite concentration and bacterial abundance in the rhizosheath. We propose that the complex interactions of root, microbes and rhizodeposits in the rhizosheath have the potential to regulate water uptake by crops. The root and rhizosheath traits highlighted here can be targeted to develop crops with better ability to uptake water.