The present invention pertains to an auxin receptor protein involved in activation of proton pump in plasma membrane of a plant derived from rice, a gene encoding the protein, a recombinant vector comprising the gene, a host cell transformed with the recombinant vector, a method of improving traits of a plant by transforming the plant with the recombinant plant expression vector, a plant having improved traits by transformation with the recombinant plant expression vector and seeds of the plant, and a composition comprising the gene of the invention for improving traits of a plant.
