The NitroFixSal project was organized into four interconnected work packages (WP1-WP4) to achieve the main goals of the project.
In WP1, the initial task involved crafting a membrane sensor. Various N-free media with diverse element sources and a dye for the detection of active bacteria were employed. This invention holds promise for biotech firms producing biofertilizers based on nitrogen-fixing bacteria.
Within WP2, the focus shifted to screening N2-fixing bacteria from the rhizospheres of wheat, maize, Aster tripolium, and Salicornia europea grown in technosoils near soda lime repository ponds of CIECH Soda Polska S.A. Over 60 halotolerant strains were obtained from the soil samples, with 11 proving to be nitrogen-fixing bacteria. A comprehensive investigation explored additional growth-promoting properties of these isolates. Notably, strains Azo12 and W4ii significantly facilitated the growth of root and leaf portions of seedlings in salt stress scenarios. Furthermore, Azo12, Azo7, and Azo11 substantially enhanced seedling growth in nitrogen-stressed conditions compared to control seedlings. The results were presented at the 7th Edition of the Global Conference on Plant Science and Molecular Biology (GPMB 2022), Paris, France (September 1-2, 2022) and during the Power of Microbes in Industry and Environment International Conference in Poreč, Croatia (May 15-18, 2023).
WP3 focused on assessing the growth promotion effects and salt stress mitigation potential of the selected PGPR isolates, W4ii and Azo12, when applied to wheat plants under saline conditions. Plant properties (e.g. height, weight, chlorophyll content, lipid peroxidation, total soluble, proline content) were examined in treated and non-treated plants. Both PGPR strains demonstrated the capacity to ameliorate the adverse effects of salt stress on wheat plants. The results were presented during the 8th Central European Congress of Life Sciences EUROBIOTECH, held in Kraków, Poland (June 20-22, 2022), and published in Open Research Europe as an associated article titled "Application of halotolerant Azotobacter chroococcum W4ii isolated from technosoils to mitigate salt stress in the wheat plant. Patent applications grounded in strain Azo12 have been developed and submitted to the Polish Patent Office under reference numbers P.444444 P.444469 and P.444472.
WP4 encompassed transcriptome analysis of wheat plants treated with W4ii and Azo12 isolates under salinity stress. The aim was to scrutinize differentially expressed genes in wheat plants following interaction with PGPR.
