It is to provide a novel molybdenum ion transporter MoTR1 gene responsible for molybdenum transport for the first time in plants, enabling to promote effectively molybdenum absorption from the environment or molybdenum transport in vivo. By QTL analysis of Arabidopsis thaliana accessions Col-0 and Ler, it was found that QTL which dominates Mo concentration in leaves was present on the chromosome No: 2. In the present invention, the region in which the causal gene is present was limited to 172 kb, by a genetic analysis. In the region, the gene At2g25680 having a domain common to sulfate ion transporter, while its function is not revealed was present. Thus, knockout strains of 2 separate lines in which a foreign gene fragment (T-DNA) was introduced at At2g25680 were obtained, Mo concentration in leaves was measured, and MoTR1 gene was identified.