If you were wondering about which genes are involved in the copper dependence of iron homeostasis in Arabidopsis, here’s your answer!
Turns out its: SQUAMOSA PROMOTER BINDING PROTEIN-LIKE7 (SPL7), FERRIC REDUCTASE OXIDASE5 (FRO5) and FERRIC REDUCTASE OXIDASE4 (FRO4).
Yep, researchers at Ruhr University, Germany discovered this with transcriptome sequencing.
They sequenced both wild-type and a mutant of Arabidopsis thaliana plants. The mutant was defective in the gene encoding SPL7. In response to Cu deficiency, FERRIC REDUCTASE OXIDASE5 (FRO5) and FRO4 transcript levels increased strongly, in an SPL7-dependent manner. Biochemical assays and confocal imaging of a Cu-specific fluorophore showed that high-affinity root Cu uptake requires prior FRO5/FRO4-dependent Cu(II)-specific reduction to Cu(I) and SPL7 function. Plant iron (Fe) deficiency markers were activated in Cu-deficient media, in which reduced growth of the spl7 mutant was partially rescued by Fe supplementation. Cultivation in Cu-deficient media caused a defect in root-to-shoot Fe translocation, which was exacerbated in spl7 and associated with a lack of ferroxidase activity. This is consistent with a possible role for a multicopper oxidase in Arabidopsis Fe homeostasis, as previously described in yeast, humans, and green algae.
These insights into root Cu uptake and the interaction between Cu and Fe homeostasis will advance plant nutrition, crop breeding, and biogeochemical research.
- Bernal M, Casero D, Singh V, Wilson GT, Grande A, Yang H, Dodani SC, Pellegrini M, Huijser P, Connolly EL, Merchant SS, Krämer U. (2012) Transcriptome Sequencing Identifies SPL7-Regulated Copper Acquisition Genes FRO4/FRO5 and the Copper Dependence of Iron Homeostasis in Arabidopsis. Plant Cell [Epub ahead of print]. [abstract]