ON THE COVER

The Casparian strip (CS) plays an important role in selective uptake of mineral nutrients in roots. Rice roots have a CS at the exodermis and the endodermis. Wang et al. (pages 2636–2648) show that Casparian strip domain protein1 (CASP1) is required for formation of the CS at endodermal cells and is localized to this region of the CS. Knockout of CASP1 resulted in decreased growth of rice compared uncontrolled flow of mineral nutrients to the stele. The cover image shows localization of lignin (magenta), CASP1-GFP (green) and cellulose (blue) in a rice root thin section. The bottom of the image shows a wild-type rice plant (left) and CASP1 knockout mutant (right).