Louis Grillet, Lan P, Li WF, Girish Mokkapati, Wolfgang Schmidt. IRON MAN is a ubiquitous family of peptides that control iron transport in plants. Nature Plants, 2018, doi: 10.1038/s4`477-018-0266-y
Abstract
Iron (Fe) is an essential mineral nutrient which severely affects the growth, yield and nutritional quality of plants if not supplied in sufficient quantities. We here report that a short C-terminal amino acid sequence consensus motif (IRON MAN; IMA) conserved across numerous, highly diverse peptides in angiosperms, is essential for Fe uptake in plants. Overexpression of the IMA sequence in Arabidopsis induced Fe uptake genes in roots, causing accumulation of Fe and manganese in all plant parts including seeds. Silencing of all eight IMA genes harbored by the Arabidopsis genome abolished Fe uptake and caused severe chlorosis; increasing the Fe supply or overexpressing IMA1 restored the wild-type phenotype. IMA1 is predominantly expressed in the phloem, preferentially in leaves, and reciprocal grafting showed that IMA1 peptides in shoots positively regulate Fe uptake in roots. IMA homologs are highly responsive to the Fe status and functional when heterologously expressed across species. IMA constitutes a novel family of peptides which are critical for the acquisition and cellular homeostasis of Fe across land plants.
