Background and Aims: Soil salinity is an increasing threat to crop production and, as a consequence, improving the level of salinity tolerance has become a priority in plant research. Biologicals, including microorganisms and biostimulants, can play a significant role in enhancing plant tolerance to salinity stress, which is further fueled by soil degradation and climate change. Methods: This review explores the mechanisms by which these agents contribute to salinity tolerance. Results: Microorganisms such as plant growth-promoting rhizobacteria, mycorrhizal or endophytic fungi improve plant resilience by facilitating nutrient uptake, producing phytohormones, and enhancing antioxidant activities. They alter root architecture and exude signals that improve water use efficiency, allowing plants to better manage osmotic stress. Biostimulants, comprising amino acids, humic substances, plant and seaweed extracts, further bolster plant tolerance by regulating ion balance and stimulating metabolic pathways associated with the stress response. Some of these substances enhance photosynthetic efficiency, thus maintaining plant growth and productivity under saline conditions. Collectively, the synergistic interaction of microorganisms and biostimulants cultivates a robust soil-plant interface, providing a sustainable strategy to mitigate the impacts of salinity. Conclusion: Continued research is needed to optimize their application methods and to understand the complex interactions within specific crop and soil systems, enabling agricultural systems to adapt to increasing soil salinity levels.

The aim of our long-term research program is to improve the quality and quantity of amaranth production through mutation breeding using γ-radiation. In this paper, we present the characterization of the new variety ‘Zobor’ of A. hypochondriacus × A. hybridus developed by radiation-induced mutagenesis of hybrid K-433. Multiyear phenotypic characterization of an important yield parameter (1000-seed weight) showed that the studied mutant variety ‘Zobor’ has an advantage in seed weight over the nonirradiated control seeds of K-433 with predictable performance of this yield trait. ‘Zobor’ exhibited changes in seed morphometric parameters, starch particle size, and pasting properties with no change in amylose content and swelling power. Moreover, the seeds of ‘Zobor’ showed the significantly highest folate content among selected amaranth varieties. The mutant variety could, therefore, be interesting for the development of functional foods and as a low-management crop, attractive for cultivation in Europe.

Main conclusion: A comparative analysis of NaCl-stressed flax genotypes reveals that microRNA828a, microRNA399g, microRNA168a, catalase, shoot length, and shoot dry weight are the most influential salt stress-responsive variables irrespective of the lignan (secoisolariciresinol diglucoside) content declared for the genotypes. Lignans are powerful antioxidants and plant defence molecules whose roles in mitigating salt stress are rarely studied or understood, particularly in flax ( Linum usitatissimum L.). Flax is a rich source of lignans. This study assessed the response to salt stress in two flax genotypes, Flanders and Astella. Astella has a higher content of the lignan secoisolariciresinol diglucoside (SDG) than Flanders. The 3-week-old flax plants were subjected to 100 mM NaCl salt stress for 1 week. Morphological analyses revealed that the growth of Flanders was more suppressed under stress, indicating resource-saving behaviour compared to Astella. Salt stress caused Astella to produce more reactive oxygen species (ROS) and incur more cell damage than Flanders. Flanders exhibited comparatively higher levels of antioxidants, osmoprotection machinery, and lignan-related microRNAs, suggesting its enhanced ROS scavenging and superior cellular protection capabilities than Astella. However, multivariate analysis could not provide evidence for the direct involvement of lignans in stress adaptation. Instead, it was hypothesised that microRNAs play a pleiotropic role in the adaptation to salinity. The results demonstrated Flanders’ superiority to Astella in salt stress mitigation. The findings could be used to improve the salinity tolerance of flax and other crop plants in future research.