Leymus chinensis is a perennial forage grass that has good palatability, high yield and high feed value, but seed dormancy is a major problem limiting the widespread cultivation of L. chinensis. Here, we performed transcriptomic and metabolomic analysis of hulled and de-hulled seeds of L. chinensis treated with or without GA₃ to investigate the changes in gene and metabolites associated with dormancy release induced by GA₃. The germination test revealed that the optimum concentration of GA₃ for disruption of L. chinensis seed dormancy was 577 μM. A total of 4327 and 11,919 differentially expressed genes (DEGs) and 871 and 650 differentially abundant metabolites were identified in de-hulled and hulled seeds treated with GA₃, respectively, compared with seeds soaked in sterile water. Most of the DEGs were associated with starch and sucrose metabolism, protein processing in the endoplasmic reticulum, endocytosis and ribosomes. Furthermore, isoquinoline alkaloid biosynthesis, tyrosine metabolism, starch and sucrose metabolism, arginine and proline metabolism, and amino sugar and nucleotide sugar metabolism were significantly enriched pathways. Integrative analysis of the transcriptomic and metabolomic data revealed that starch and sucrose metabolism is one of the most important pathways that may play a key role in providing carbon skeletons and energy supply for the transition of L. chinensis seeds from a dormant state to germination by suppressing the expression of Cel61a, egID, cel1, tpsA, SPAC2E11.16c and TPP2, enhancing the expression of AMY1.1, AMY1.2, AMY1.6 and GLIP5, and inhibiting the synthesis of cellobiose, cellodextrin, and trehalose while promoting the hydrolysis of sucrose, starch, cellobiose, cellodextrin, and trehalose to glucose. This study identified several key genes and provided new insights into the molecular mechanism of seed dormancy release induced by GA₃ in L. chinensis. These putative genes will be valuable resources for improving the seed germination rate in future breeding studies.

Waxy maize (Zea mays L. sinensis Kulesh) is highly regarded for its high nutritional content and unique taste. Although the stalks and leaves contain high carbohydrate levels after ear harvesting, inadequate crude protein (CP) limits the utilization and promotion of waxy maize silage in animal husbandry. In this study, waxy maize and fodder soybeans were mixed for sowing in different proportions [1:0 (CK), 1:1 (A1), 1:2 (A2), 1:3 (A3), and 1:4 (A4)] to investigate the effects of different mixing ratios on the growth of the waxy maize, the chemical indices, fermentation quality, and the microbial community of the mixed silage after ear harvesting. The mixed planting of waxy maize and fodder soybeans in different proportions had no effect on the yield and quality of the waxy maize ears and increased the aboveground biomass after ear harvesting. After ear harvesting, the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents significantly decreased, and the CP content and relative feeding value (RFV) gradually increased in the mixed silage. The pH of the treatments was lower than 4.2 except for A4, and the lowest ammonia nitrogen (AN) concentration was observed in A3. With increasing proportions of fodder soybeans, the abundance of beneficial bacteria increased and that of harmful bacteria decreased; Firmicutes and Lactobacillus were the dominant phylum and genus, respectively, and both increased gradually. Redundancy analysis (RDA) revealed that the fermentation indices affecting the microbial community composition in the silage were inconsistent among the different mixed sowing combinations. The Mantel test showed that the composition of the microbial communities in the treatments was significantly correlated with the ADF, water-soluble carbohydrate (WSC), and propionic acid (PA) contents. Comprehensive analysis revealed that the optimal mixed sowing ratio of waxy maize to fodder soybeans was 1:3, and waxy maize and fodder soybeans silage can increase the utilization of aboveground biomass and improve the fermentation quality and feeding quality of silage by changing the microbial community. These findings lay a certain theoretical foundation for improving the utilization of waxy maize.

Alfalfa root rot caused by Fusarium tricinctum is one of the most important soilborne diseases, resulting in significant losses to alfalfa agriculture worldwide. Fungicides used in management of the disease affect the environment and human health. In this study, a strain of Ochrobactrum intermedium (I-5), isolated from alfalfa rhizosphere soil, exhibited strong antifungal activity against a number of causative pathogens of alfalfa root rot and showed the strongest antagonistic activity against F. tricinctum (a longest radius/shortest radius ratio of 3.09). When applied at 10%, a filtrate of the strain liquid culture significantly reduced the spore production and germination and mycelial growth of F. tricinctum, and the inhibition rates were 76.67, 78.93, and 55.77%, respectively. Furthermore, a filtrate and suspension of the strain, when applied at 10%, reduced alfalfa root rot by >73% in repeated experiments. The strain clearly promoted the activities of invertase, urease, cellulose, and neutral phosphatase in alfalfa rhizosphere soil and significantly reduced the damage to rhizosphere soil quality attributable to alfalfa root rot. Moreover, the strain clearly promoted the growth of alfalfa without causing any evident damage to plants. The active substance produced by the strain was insensitive to heat and ultraviolet irradiation and displayed optimal efficacy at pH 8. To the best of our knowledge, this is the first study describing the use of O. intermedium for the biological control of alfalfa root rot. O. intermedium (I-5) has potential for application in the control of alfalfa root rot and improvement of the quality of cultivated alfalfa.

Drought is a critical limiting factor for crop yield, posing a substantial threat to global food security and negatively influencing plant growth and development. As a crop used as both a grain and forage, the yield of oat (Avena sativa) is significantly affected by drought. Glutamine synthetase (GS) is a crucial enzyme in plant nitrogen metabolism and plays an essential role in nitrogen utilization, growth regulation, and yield formation. We used bioinformatics analysis to identify the GS gene family in oats, and employed molecular biology, genetics and plant physiology methods to investigate the drought-resistant function of AsGS2-2C . In this study, 11 oat AsGS genes were identified, and the gene family and expression patterns were analyzed. Our findings revealed that a majority of AsGS genes were upregulated under drought and salt stress, whereas they were downregulated in response to cold stress and abscisic acid treatment. Cloning and functional analysis of the AsGS2-2C gene revealed that transgenic tobacco overexpressing AsGS2-2C presented increased tolerance to drought stress in phenotype. Physiological analyses revealed an increase in antioxidant enzyme activities and a reduction in membrane damage in AsGS2-2C-overexpressing plants. Under drought conditions, the expression of stress-responsive genes ( Cu/Zn-SOD, MnSOD, CBL1, GR1, GAPC, Gln1-5 , and BI-1 ) was significantly elevated in AsGS2-2C transgenic tobacco. Interestingly, ACR11, GLU, ERD10B, Hxk3 and Ltp1 exhibited initial upregulation followed by subsequent downregulation. These findings provide valuable insights into the molecular mechanisms underlying drought tolerance mediated by AsGS2-2C in oat, offering potential targets for crop improvement against drought.

A high salt environment seriously affects the physiological metabolism and yield of plants. Hordeum brevisubulatum (Trin.) Link has high biomass and important ecological, feeding and economic values, but its growth conditions have serious saline-alkali effects. The NHX gene family plays a vital role in regulating intracellular Na⁺/K⁺ balance, pH homeostasis, and vesicle and protein transport in plants. In this study, the HbNHX2 gene was cloned from Hordeum brevisubulatum and functionally characterized through phenotypic, physiological, and molecular analyses in transgenic tobacco. Expression profiling revealed that HbNHX2 was most abundant in spikes and least abundant in root tips, and the expression level was significantly induced under salt stress. Overexpression of HbNHX2 led to decreased malondialdehyde (MDA) and superoxide anion (O²⁻) levels, while it enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Additionally, the levels of glutathione (GSH), soluble proteins, proline, and chlorophyll were also increased. Several stress-responsive genes, including CBL1, ERF2, BI-1, Cu/Zn-SOD, Mn-SOD, POD, GR1, KC1, TPK1, TIP, P5CS, BAS1, STN7 and LTP1, were significantly upregulated, while SERK3B was downregulated. These findings suggest that HbNHX2 enhances plant salt tolerance by maintaining osmotic balance, scavenging reactive oxygen species (ROS), and regulating stress-responsive gene expression. This study provides new insights into the molecular mechanism of salt tolerance in Hordeum brevisubulatum and lays a foundation for breeding salt-tolerant forage crops.