New observations to enhance the utilization of iron by crops

March 3, 2026

Identification of a new transporter of “coumarin,” an iron-chelating substance

Iron is a nutrient that is essential to the growth of plants; however, it usually exists in an insoluble form in soil and it is difficult for plants to efficiently absorb iron. When iron is lacking, Brassicaceous plants secrete iron-mobilizing “coumarin” from their roots to promote iron acquisition. Coumarin is widely known to be secreted from the epidermal and cortical cells of the roots, but the way coumarin accumulates within these cells and its molecular mechanism have not yet been clarified.

A joint research group from Yasuda Women’s University, INRAE/IPSiM (France), University of the Ryukyus, and the RIKEN CSRS discovered that NPF7.2, a member of the NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY (NPF) in Arabidopsis thaliana, is a coumarin import transporter that “loads” coumarin into the epidermal and cortical cells of the roots. The group revealed that NPF7.2 is expressed in the root epidermal and cortical cells under iron deficiency to concentrate and hence to promote coumarin secretion from these cells. These results further advance our understanding of the iron acquisition mechanism of Brassicaceous plants.

The findings from this study are expected to be applied to the development of crops that grow well in iron-deficient soils and to biofortification that increases iron content and nutritional value in the future.

 

Original article

New Phytologist　doi: 10.1111/nph.70993

S. Watanabe, M. Li, A. Rossille, C. Boustani, K. Robe, Y. Kanno, M. Seo, C. Dubos,

"The Arabidopsis NPF7.2 mediates coumarin uptake for root iron acquisition".

Contact

Mitsunori Seo
Senior Visiting Scientist
Mass Spectrometry and Microscopy Unit