Genetic dissection of Fe-dependent signaling in root developmental responses to phosphate deficiency ($)

Phosphate deficiency leads to arrest of primary root elongation. Previous work has shown that this arrest depends upon Fe, raising the possibility that Fe accumulation in the root apex is the cause of growth arrest. Several genes involved in low Pi response have been identified, including genes encoding the LPR1 ferroxidase, ALS3/STAR1 transporter complex and the STOP-ALMT1 regulatory module; however, how these components interact has been unclear. Wang et al. carry out side-by-side comparisons of growth and Fe-uptake responses to Pi deficiency in various combinatorial mutants and overexpressor lines, allowing them to be placed into a genetic pathway of function, and revealing that “the degree of the inhibition of PR growth is not simply linked to the level of Fe accumulated in the RAM or elongation zone.” (Summary by Mary Williams)  Plant Physiol. 10.1104/pp.18.00907