Soil salinization limits the growth of agricultural crops in the world, requiring the use of methods to increase the tolerance of agricultural crops to salinity–alkali stress. Arbuscular mycorrhizal fungi (AMF) enhance plant stress adaptation through symbiosis and offer a promising strategy for remediation. However, in non-model crops such as oat (Avena sativa L.), research has mainly focused on physiological assessments, while the key genes and metabolic pathways involved in AMF-mediated growth and saline–alkali tolerance remain unclear. In this study, we employed integrated multi-omics and physiological analyses to explore the regulatory mechanisms of AMF in oats under normal and saline–alkali stress. The results indicated that AMF symbiosis significantly promoted oat growth and physiological performance under both normal and saline–alkali stress conditions. Compared to the non-inoculated group under normal conditions, AMF increased plant height and biomass by 8.5% and 15.3%, respectively. Under saline–alkali stress, AMF enhanced SPAD value and relative water content by 16.7% and 7.3%, reduced MDA content by 35.8%, increased soluble protein by 21.8%, and decreased proline by 13.3%. In addition, antioxidant enzyme activities (SOD, POD, and CAT) were elevated by 18.4%, 18.2%, and 14.8%, respectively. Transcriptomic analysis revealed that AMF colonization under saline–alkali stress induced about twice as many differentially expressed genes (DEGs) as under non-saline–alkali stressed conditions. These DEGs were primarily associated with Environmental Information Processing, Genetic Information Processing, and Metabolic Processes. According to metabolomic analysis, a total of 573 metabolites were identified across treatments, mainly comprising lipids (29.3%), organic compounds (36.8%), and secondary metabolites (21.5%). Integrated multi-omics analysis indicated that AMF optimized energy utilization and antioxidant defense by enhancing phenylpropanoid biosynthesis and amino acid metabolism pathways. This study provides new insights into how AMF may enhance oat growth and tolerance to saline–alkali stress.

In the field of agro-grassland, the synergism of phosphate (P) fertilization and Trichoderma inoculation in alfalfa production and the underlying mechanism of rare and abundant microbes that regulate rhizosphere soil processes in various environments are key but rarely studied topics. Here, we conducted field research through the inoculation/noninoculation of Trichoderma and five levels of phosphorus fertilizer to explore the biological relationships of rhizosphere soil properties, rare and abundant taxa, and alfalfa yields. Our results demonstrate that using Trichoderma inoculation and 15 g/m² of phosphorus fertilizer exhibited optimal alfalfa yield compared with other treatments. alfalfa yields significantly (R² = 0.33; p < 0.001) increased along with soil fertility. Both rare (R_ANOSIM = 0.900; p = 0.001) and abundant (R_ANOSIM = 0.769; p = 0.001) bacterial communities were significantly different under Trichoderma inoculation and P fertilization in a nonmetric multidimensional scaling (NMDS) analysis. Furthermore, different ecological processes dominated the rare and abundant bacterial community assembly. PLS-PM analysis showed that Trichoderma inoculation positively regulated the abundant bacteria community and P fertilization regimes manipulated the rare bacteria community, synergistically contributing to alfalfa yields. Overall, this article believes that inoculation with Trichoderma and appropriate application of phosphorus fertilizer can significantly increase alfalfa yield and affect soil enzyme activity, and the rhizosphere soil abundant and rare bacterial community characteristics have different responses to the synergistic effect of Trichoderma and phosphorus fertilizer. Our research emphasizes the fundamental role of abundant and rare microbes in maintaining crop production using Trichoderma inoculation and P fertilization. Therefore, distinguishing rare and abundant species is beneficial to comprehensively understanding microbial-driven processes and providing theoretical support for maintaining ecosystem productivity.

Background: The Alxa Region in Inner Mongolia, northwest China is a desert grassland area. Wild alfalfa growing in this area is a precious wild plant resource that can provide resources for improving the stress resistance of alfalfa varieties. Alfalfa is a cross-pollinated plant and its genes are commonly heterozygous. Therefore, establishing a complete tissue culture regeneration system for a single plant is an effective method of protecting wild plant resources. This study used the bud and leaf of wild alfalfa from the Alxa Region as explants to establish an efficient and stable tissue culture regeneration system. Methods: Two kinds of wild alfalfa tissues were selected as explants. Different concentrations and types of plant growth hormones and regulators were tested, to determine the optimal medium for callus induction, differentiation and rooting culture, including 6-Benzylaminopurine (6-BA), Kinetin (KT), 2, 4-Dichlorophenoxyacetic acid (2, 4-D), Naphylacetic acid (NAA), Indole-3-butyric acid (IBA) and activated carbon (AC). Result: The callus induction rate was 93.3% when the bud of wild alfalfa was used as an explant for propagation. With a basic medium (Murashige and Skoog medium with Ca2+, Mg2+ and Mn2+ halved) and hormone regulator (6-BA, KT, NAA, AC), the differentiation rate and rooting rate reached as high as 66.67% and 93.33%, respectively. When leaves were used as explants, the callus induction rate and differentiation rate were 100% and 73.33%, respectively. In the rooting culture process, adding IBA (0.2 mg/L) and AC (0.5 mg/L) to the medium improved the rooting rate of wild alfalfa. Both buds and leaves can be used as explants for plant tissue regeneration and culture, which can help expand and preserve wild alfalfa resources.

Soil antibiotic resistant genes (ARGs) and mobile genetic elements (MGEs) are associated with agricultural land-use differences. However, assessing the soi

Background: Salt stress imposes osmotic imbalance and ion toxicity, severely impairing crop growth and development. Na⁺/H⁺ antiporters (NHXs) play a central role in salt tolerance by mediating sodium transport across cellular membranes. Results: We conducted a genome-wide characterization of the NHX gene family in four hexaploid oat cultivars, identifying 126 NHX genes. These were grouped into 33 orthologous gene groups (OGGs), comprising 10 core and 23 dispensable OGGs. The naked oat cultivar ‘Sanfensan (SFS)’ contained the largest number of both total and core NHX genes. Phylogenetic analysis classified AsNHX genes into three classes: vacuolar (Vac-class), endosomal (Endo-class), and plasma membrane (PM-class). Ka/Ks analysis indicated strong purifying selection across most members. Cis -regulatory element analysis revealed abundant stress-related motifs, including abscisic acid (ABA) and methyl jasmonate (MeJA) response elements, suggesting roles in abiotic stress adaptation. Transcriptome and qRT-PCR data confirmed that AsNHX1/3/7/9/14/23/24/25/32 were up-regulated under salt stress, highlighting their importance in salinity tolerance. Conclusions: This study provides the first comprehensive characterization of the AsNHX gene family, detailing their evolutionary, structural, and functional features. The findings offer critical insights into salt adaptation mechanisms in oat and identify promising targets for genetic improvement of salinity tolerance.