A sensitive LC‐ESI‐Q‐TOF‐MS method reveals novel phytosiderophores and phytosiderophore–iron complexes in barley

Summary • The direct analysis of phytosiderophores (PSs) and their metal complexes in plants is critical to understanding the biological functions of different PSs. Here we report on a rapid and highly sensitive liquid chromatography-electrospray ionization-quadrupole-time of flightmass spectrometry (LC-ESI-Q-TOF-MS) method for the direct and simultaneous determination of free PSs and their ferric complexes in plants. • In addition to previously reported PSs ‐ deoxymugineic acid (DMA), mugineic acid (MA) and epihydroxymugineic acid (epi-HMA) ‐ two more PSs, avenic acid (AVA) and hydroxyavenic acid (HAVA), were identified by this method in roots of Hordeum vulgare cv Himalaya and in root exudates under iron (Fe) deficiency. • The two identified PSs could be responsible for Fe acquisition under Fe deficiency because of their relative abundance and ability to form ferric complexes in secreted root exudates. • This LC-ESI-Q-TOF-MS method greatly facilitates the identification of free PSs and PS‐Fe complexes in one plant sample.