Lsi2 (low silicon 2) gene encodes a rice silicon efflux transporter. It is constitutively expressed in the root, the protein is localized on the plasma membrane in both the exodermis and the endodermis of the proximal side of the same cell, in contrast to Lsi1 (silicon influx transporter), which is localized on the distal side. lsi2 mutant showed reduced growth and grain discoloration due to the low accumulation of siicon in the shoot and hull in the mutant. Lsi2 is capable of transportng silicon out of the cells, together with Lsi1, rice silicon transporter reveal a unique mechanism of nutrient transport in plants.