Authors:
Andreea Spiridon | University of Natural Resources and Life Sciences (BOKU) Vienna | Austria
Dr. David Aleksza | University of Natural Resources and Life Sciences (BOKU) Vienna | Austria
Assoc. Prof. B.Sc. PD Ph.D. Tim Causon | University of Natural Resources and Life Sciences (BOKU) Vienna | Austria
Univ.Prof. Dr. Stephan Hann | University of Natural Resources and Life Sciences (BOKU) Vienna
Dr. rer. nat. Nicolas Kratena | Vienna University of Technology (TU Wien)
Dipl.-Ing. Dr.techn. Christian Stanetty | Vienna University of Technology (TU Wien)
Priv.-Doz. Dipl.-Ing. Dr. Eva Oburger | University of Natural Resources and Life Sciences (BOKU) Vienna
Micronutrient (MN) deficiency in crops is prevalent in arid and semi-arid regions with high pH soils. Effective strategies for acquiring MN are essential to ensure high yields on nutrient-depleted soils and produce MN-rich crops. In the case of iron (Fe), graminaceous plants increase Fe phytoavailability by releasing root exudates called phytosiderophores (PS). However, PS can also complex other MNs, like zinc (Zn) and copper (Cu). There are eight naturally occurring PS: MA, HMA, epi-HMA, HAVA, DMA, HDMA, epi-HDMA, and AVA. While previous research has focused on DMA, occasionally on MA, and primarily on Fe deficiency, our study delves into the significance of PS biosynthesis and exudation of all eight PS across different barley genotypes when exposed to either Zn, Cu, or Fe deficiencies, considering both hydroponic and soil-based systems. Moreover, we investigated if different PS exhibit disparities in their efficiency in mobilizing MN by conducting soil interaction experiments between all eight PS and MN deficient soils. Our findings showed that the PS pathway was activated not only under Fe, but also under Zn and Cu deficiency. Additionally, we observed a significant genotype-dependent effect among the tested barley genotypes, with efficient genotypes exhibiting increased PS biosynthesis and release. Our soil-PS interaction experiments revealed that PS-aided metal mobilization is specific to soil type and shows similar trends as the DTPA-available metal fraction. We also observed differences in their metal mobilization efficiencies, which were time and PS-concentration dependent. Our findings provide valuable insights into the complex dynamics of PS-mediated MN uptake, laying the groundwork for improving future plant breeding programs to cope with MN-deficient soils.