A sensitive LC-ESI-TOF-MS method for the detection of phytosiderophores and their iron complexes in roots
Under Fe deficiency, plant roots secrete specific compounds such as organic acids and phytosiderophores into the rhizosphere to increase Fe bioavailability by changing the soil pH or by binding to ferric Fe. Phytosiderophores are non-proteinogenic amino acids. The biosynthesis and secretion of phytosiderophores are specific to graminaceous plants. The acquisition of Fe from soil by grasses by phytosiderophores and a chelation-based mechanism is called strategy II, whereas non-grass plants use a reduction-based mechanism termed strategy I. The direct analysis of phytosiderophores and their metal complexes is critical to understand the biological functions of different phytosiderophores. Here we report on a rapid and highly sensitive LC-ESI-TOF-MS method for the direct and simultaneous determination of free phytosiderophores and their ferric complexes in plants. With the developed platform, we identify two novel phytosiderophores, AVA and HAVA in barley.