Modulation Of Phosphate Deficiency-Induced Metabolic Changes By Iron Availability In Arabidopsis Thaliana

Concurrent suboptimal supply of several nutrients requires the coordination of nutrient-specific transcriptional, phenotypic, and metabolic changes in plants in order to optimize growth and development in most agricultural and natural ecosystems. Phosphate (P-i) and iron (Fe) deficiency induce overlapping but mostly opposing transcriptional and root growth responses in Arabidopsis thaliana. On the metabolite level, P-i deficiency negatively modulates Fe deficiency-induced coumarin accumulation, which is controlled by Fe as well as P-i deficiency response regulators. Here, we report the impact of Fe availability on seedling growth under P-i limiting conditions and on P-i deficiency-induced accumulation of amino acids and organic acids, which play important roles in P-i use efficiency. Fe deficiency in P-i replete conditions hardly changed growth and metabolite profiles in roots and shoots of Arabidopsis thaliana, but partially rescued growth under conditions of P-i starvation and severely modulated P-i deficiency-induced metabolic adjustments. Analysis of T-DNA insertion lines revealed the concerted coordination of metabolic profiles by regulators of Fe (FIT, bHLH104, BRUTUS, PYE) as well as of P-i (SPX1, PHR1, PHL1, bHLH32) starvation responses. The results show the interdependency of P-i and Fe availability and the interplay between P-i and Fe starvation signaling on the generation of plant metabolite profiles.