The study aimed to isolate, characterize, and identify wild lactic acid bacteria (LAB) strains from native grass silage on the Inner Mongolian Plateau, and the effects of wild LAB strains on the nutritive and fermentation characteristics of sorghum–sudangrass hybrid (Sorghum bicolor L. × S. sudanense L.) silage were also investigated. These isolates were evaluated using morphological, physiological, and biochemical tests. Three isolated strains were Gram‐positive, homofermentative, catalase‐negative, not produce gas from glucose, and rod‐shaped. These strains could grow normally at pH 3.5–8.0, 15–30 ˚C and NaCl 3 and 6.5%. They were identified as Lactobacillus plantarum group by sequencing 16S rRNA. Compared to uninoculated silage, all LAB‐inoculated silages significantly (P < .05) increased lactic acid (LA) content and ratios of lactic acid/acetic acid (LA/AA), while, reduced pH and ammonia nitrogen (NH₃–N). Among all the isolated LAB strains, XM2 showed the highest (P < .05) crude protein (CP), LA, ratio of LA/AA and LAB, lowest (P < .05) pH, AA, propionic acid (PA), butyric acid (BA), NH₃–N than the other isolated LAB strains. Strain XM2 is a potential starter culture for sorghum–sudangrass hybrid silage.

This study aimed to isolate and identify lactic acid bacteria (LAB) from the native grass and naturally fermented silage from the Mongolian Plateau. The effect of selected strains on bacterial community and quality of native grass silage was also studied. Strains XM2, 265, and 842 could grow normally at 15°C–30°C, pH 4.0–8.0, and NaCl 3 and 6.5%; they were identified as Lactiplantibacillus plantarum subsp. plantarum, Pediococcus acidilactici, and Latilactobacillus graminis, by sequencing 16S rRNA, respectively. The three strains (XM2, 265, and 842) and one commercial additive (L) were used as inoculants and singularly added to the native grass. Compared to the control, the dry matter content was significantly (p < 0.05) lower in L and XM2 groups. The water-soluble carbohydrate content was significantly (p < 0.05) higher in control than in other groups. Compared with the control, the crude protein and ammonia nitrogen contents were significantly (p < 0.05) higher and lower in the LAB-treated groups, and the acid and detergent fiber contents were significantly (p < 0.05) reduced in the L and XM2 groups than those in other groups. There was a significant (p < 0.05) difference in the pH value, lactic acid content, and lactic acid-to-acetic acid ratio in L and XM2 groups than in other groups. Compared with the control, the number of LAB was significantly (p < 0.05) higher in LAB-treated silages, whereas no significant (p > 0.05) differences were observed in yeast and aerobic bacteria in all groups. Compared to the control, the Shannon index was significantly (p < 0.05) reduced. Simpson and Chao1 were significantly (p < 0.05) increased. Principal coordinate analysis based on the unweighted UniFrac distance showed clear separation of the bacterial community in fresh materials and LAB-treated silages. Besides, compared to the control, the principal coordinate analysis of LAB-treated silages was also separate. After 30 days of fermentation, the relative abundance of Firmicutes increased and was the primary phylum in all silages. Compared with the control, the abundance of Firmicutes and Proteobacteriawas significantly (p < 0.05) higher and lower in L and XM2 groups. In contrast, no significant differences were observed among control, 265, and 842 groups. At the genus level, the relative abundance of Lactobacillus, Enterobacter, Pediococcus, and Weissella was increased and dominated the native grass fermentation. Compared with the control, the abundance of Lactobacillus was significantly (p < 0.05) higher in L, XM2, and 842 groups, while no significant (p > 0.05) differences were observed between the control and 265 groups. The abundance of Pediococcus was higher than that in other groups. Consequently, the results demonstrated that LAB significantly influenced silage fermentation by reconstructing microbiota, and Lactobacillus was the dominant genus in the native grass silages. Furthermore, the results showed that strain XM2 could effectively improve the silage quality, and it is considered a potential starter for the native grass silage.

Apocynum venetum L. belongs to the Apocynaceae family and is a plant that is highly resistant to stress. It is important in the fields of ecology, feeding, industry and medicine. The molecular mechanism underlying salt tolerance has not been elucidated. In this study, RNA-seq based transcriptome sequencing of A. venetum leaves after 0, 2, 6, 12, 24 and 48 h of treatment with 300 mM NaCl was performed. We conducted a comprehensive analysis of the transcriptome expression profiles of A. venetum under salt stress using the WGCNA method and identified red, black, and brown as the core modules regulating the salt tolerance of A. venetum. A co-expression regulatory network was constructed to identify the core genes in the module according to the correlations between genes. The genes TRINITY_DN102_c0_g1 (serine carboxypeptidase), TRINITY_DN3073_c0_g1 (SOS signaling pathway) and TRINITY_DN6732_c0_g1 (heat shock transcription factor) in the red module were determined to be the core genes. Two core genes in the black module, TRINITY_DN9926_c0_g1 and TRINITY_DN7962_c0_g1, are pioneer candidate salt tolerance-associated genes in A. venetum. The genes in the brown module were mainly enriched in two pathways, namely photosynthesis and osmotic balance. Among them, the TRINITY_DN6321_c0_g2 and TRINITY_DN244_c0_g1 genes encode aquaporin, which is helpful for maintaining the cell water balance and plays a protective role in defending A. venetum under abiotic stress. Our findings contribute to the identification of core genes involved in the response of A. venetum to salt stress.

Background: Alfalfa crops are subject to intercalation when grown continuously on the same field, and autotoxicity appears to be another factor in this thinning. Alfalfa fields are often thinned out and have lower yields during consecutive production, and autotoxicity is increasingly found to be a major reason. Hence, Therefore, understanding the seed germination and seedling growth and physiological mechanisms of the alfalfa under continuous cropping system becomes important for sustainable the use of alfalfa grassland. Methods: The leaves, stem, root and rhizosphere soil of alfalfa (Medicago sativa L. cv ZhongMu No.1) were collected to determine the seedling growth germination index (GI) and vigor index(VI), physiological characters malondialdehyde (MDA), proline, Soluble sugar (SS), Soluble protein (SP), Superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). Result: The germination rate, germination potential, germination index (GI) and vigor index decreased with the increasing extract contents, particularly in leaf extracts. In the extract of plant and soil, the concentration of malondialdehyde altered indistinctly, while the contents of osmo-regulatory substances and the activities of anti-oxidative enzymes generally decreased. Furthermore, the extract increased the seedling length of alfalfa and GI was negatively correlated with seedling growth characteristics.