Two genes PvXTH9 and PvXTHb have been suggested to regulate the polyethylene glycol-reduced cell-wall Al accumulation in root tips. Through the spatial and temporal analysis of Al-inhibited root elongation, Al accumulation, XTH genes expression and XET enzyme action in root tips, Zhang et al. further demonstrated the regulatory role of XTH genes and XET enzyme in cell-wall Al accumulation.

The results provide novel insights into the physiological and molecular mechanisms of cell-wall structure modification as a response of plant roots to osmotic stress that will assist mitigation of Al and drought stresses severely limiting crop yields on acid soils.