Iron (Fe) deficiency has become one of the factors limiting plant quality and productivity around the world. IMA (IRONMAN), a family of small peptides, has been recently reported to play a positive role in the Fe deficiency response in Arabidopsis and rice (Oryza sativa). Two OsIMA genes were identified in rice. However, it was still unclear how OsIMA1 and OsIMA2 activate the Fe deficiency response in rice.