Limonium angustebracteatum is a halophyte endemic to the E and SE Iberian Peninsula with interest in conservation. Salt glands represent an important adaptive trait in recretohalophytes like this and other Limonium species, as they allow the excretion of excess salts, reducing the concentration of toxic ions in foliar tissues. This study included the analysis of the salt gland structure, composed of 12 cells, 4 secretory and 8 accessory. Several anatomical, physiological and biochemical responses to stress were also analysed in adult plants subjected to one month of water stress, complete lack of irrigation, and salt stress, by watering with aqueous solutions of 200, 400, 600 and 800 mM NaCl. Plant growth was inhibited by the severe water deficit and, to a lesser extent, by high NaCl concentrations. A variation in the anatomical structure of the leaves was detected under conditions of salt and water stress; plants from the salt stress treatment showed salt glands sunken between epidermal cells, bordered by very large epidermal cells, whereas in those from the water stress treatment, the epidermal cells were heterogeneous in shape and size. In both, the palisade structure of the leaves was altered. Salt excretion is usually accompanied by the accumulation of salts in the foliar tissue. This was also found in L. angustebracteatum, in which the concentration of all ions analysed was higher in the leaves than in the roots. The increase of K⁺ in the roots of plants subjected to water stress was also remarkable. The multivariate analysis indicated differences in water and salt stress responses, such as the accumulation of Na and Cl, or proline, but K⁺ homeostasis played a relevant role in the mechanism of tolerance to both stressful conditions.

Aims: Root exudates play a central role in rhizosphere processes, many of which support plant growth. While increased exudation under abiotic stresses has been frequently linked to enhanced plant resilience, crop- and genotype- and soil-specific exudation patterns under non-stress conditions remain poorly understood. This study aimed to assess how soil type and genotype influence root exudation in major and emerging European crops and to explore how root morphology and plant growth are related to exudation. Methods: Four genotypes each of barley ( Hordeum vulgare ), faba bean ( Vicia faba ), potato ( Solanum tuberosum ), and sweet potato ( Ipomoea batatas (L.) Lam.) were grown in three distinct European soils under non-stress conditions. Exudates were collected using a soil-hydroponic-hybrid approach and analysed for dissolved organic carbon and nitrogen, as well as total carbohydrates, amino acids, and phenolic compounds. Biomass and root morphology were assessed to examine correlations with exudation patterns. Results: Results showed that soil type and genotype affected exudation patterns, but their influence varied by crop. Plant growth was negatively correlated with exudation rates across most crops, likely reflecting a trade-off in carbon and nitrogen allocation between biomass accumulation and rhizodeposition. Root morphological traits partly correlated with root exudation rates, but no universal relationships were detected across crops. Conclusion: Our results provide novel insights into belowground resource partitioning and broaden the understanding of exudation patterns to previously underexplored crops, highlighting resource allocation trade-offs shaped by genotype and soil as important drivers of exudation dynamics.

Aims: Soil-borne pathogens can severely compromise legume cultivation and, consequently, plant-based protein production by triggering root rot, particularly in pea ( Pisum sativum L.). Although some pea genotypes exhibit enhanced performance compared to others under root rot stress, breeding efforts have so far achieved only limited resistance. Microbiome-mediated breeding might show more success in alleviating root rot. We hypothesized that some root‑associated microbes serve as resistance markers across diverse soils. We therefore determined whether certain fungi or mycobiome attributes consistently associated with a genotype's resistance across a diverse range of soils. Methods: Root-associated fungal communities of eight pea genotypes differing in root rot resistance were characterized by ITS amplicon sequencing in four soils with contrasting infestation levels under controlled conditions. We employed alpha and beta diversity, as well as differential abundance analyses, to detect genotype- and soil-specific patterns and associations with resistance traits. Results: Both genotype and soil identity influenced alpha diversity. Evenness was reduced in infested soils, as OTU richness increased. Fungal community composition covaried with infestation level, genotype and previously defined resistance levels of the genotypes. A single OTU (OTU3), showing 100% sequence similarity to a previously identified heritable, resistance-associated hub taxon ( Dactylonectria ), was consistently enriched in resistant genotypes across soils and was positively correlated with seed emergence. Conclusions: Our results reveal OTU3 as a common microbial resistance marker, highlighting the potential of microbiome-mediated root rot resistance breeding in legumes. The uncovered phenomenon may represent a promising avenue to promote sustainable legume cultivation.