Periodic Reporting for period 1 - PhytoTrace (Wanted: Micronutrients! Phytosiderophore-mediated acquisition strategies in grass crops)
Reporting period: 2019-03-01 to 2020-08-31
AIM 2 - Reveal PS release, re-uptake and molecular responses of contrasting barley cultivars under Zn, Cu and as a reference Fe deficiency in different experimental conditions (BOKU).
Selection of suitable barley lines & optimization of growth conditions: Fe, Zn & Cu seed tissue concentrations of barley grown on a micronutrient deficient soil at the James Hutton Institute (collaboration Tim George & Soren Husted) were determined to allow a pre-selection of several lines with highest and lowest micronutrient (MN) tissue concentrations. Micronutrient (MN) deficient soils from Turkey, Australia and Spain were imported and fertilization schemes and growth conditions were optimized for barley.
Maturity growth test & gene expression analysis: 3 MN efficient and 1 MN inefficient barley lines were grown to maturity on the Zn and Cu deficient soils including their respective fertilized controls. Plants were destructively sampled at 4 time points during plant development to link growth performance (biomass), MN uptake with PS exudation and gene expression. For gene expression analysis, gene specific primers were designed for genes participating in the PS synthesis, export, and import of PS-metal complexes. The gene selection was based on previous results from the literature and on in silico investigations in different crop species focusing on the most homologous genes of this pathway. Gene expression analysis is currently conducted.
AIM 3 - Uncover the efficiency and dynamics of PS-metal mobilization of all known PS in bulk and rhizosphere soil (BOKU).
PS analysis: An indirect Fe-binding assay that allows a quick screening of the sum of all Fe solubilizing metabolites in exudate samples was implemented. Using the synthesized PS, LC-MS/MS based method was successfully adapted and implemented.
Experimental soils: general soil parameters were determined as a basis for further geochemical experiments.
AIM 4 - Elucidate the partitioning dynamics of PS in the plant-soil-microbe system and identify the key microbial players involved (BOKU, UNIVIE). Experimental work is scheduled to start in March 2021.
- Successful development and implementation of an advanced LC-MS/MS analysis of all eight PS including the use of a 13C labelled internal standard. This milestone now allows us tu accurately identify and quantify PS in root exudation and soil samples.
- Investigation of PS exudation patterns and related gene expression during plant development form barley lines differing in micronutrient use efficiency grown on Zn and Cu deficient soils