Chemical and Biological Technologies in Agriculture最新文献

Background

The mammalian gastrointestinal tract hosts a complex microbiome essential for sustaining host health, particularly during pivotal stages such as weaning in piglets. Weaning represents a significant stressor, leading to substantial shifts in the gut microbiota composition and functionality. This study investigated the impact of weaning stress on the gut microbiome and metabolite profiles of piglets, focusing on how methionine supplementation influences gut health and physiological development.

Results

A multiomics approach that integrates metagenomics, metabolomics, culturomics, and transcriptomics was employed to characterize the gut microbiota before and after weaning. During the weaning period, weaning stress was characterized by a reduction in the abundance of beneficial bacteria in the gut, particularly a significant decrease in commensal Lactobacillus species, such as L. mucosae, L. reuteri, and L. amylovorus. Metabolomic analysis further revealed reductions in methionine and other metabolites associated with methionine metabolism and reductions in branched-chain amino acids (BCAAs) and lipid-related metabolites. Analysis of culture supernatants from Lactobacillus isolates demonstrated that these commensal Lactobacillus produced methionine, methionine-related metabolites, and BCAAs, highlighting a close relationship between methionine and commensal Lactobacillus abundance under weaning stress. Moreover, methionine supplementation in intestinal epithelial cells under methionine-deficient conditions led to the upregulation of genes related to methionine and pyruvate metabolism.

Conclusions

Weaning stress results in the simultaneous reduction of both commensal Lactobacillus abundance and methionine levels in the piglet gut, with a significant inter-relationship between these factors. Methionine supplementation shows potential in mitigating gut dysbiosis and metabolic disruptions induced by weaning stress.

Graphical abstract

This study evaluated the effects of composite bacterial inoculants on the fermentation quality, microbial community composition, and nutrient preservation of natural grass silage produced in Hulunbuir, Inner Mongolia. Four treatment groups were set, each using distinct combinations of lactic acid bacteria: a control group (C) with no inoculant and three inoculated groups (Group B: Lentilactobacillus buchneri and Pediococcus pentosaceus; Group P: Lactiplantibacillus plantarum A1 and Lactiplantibacillus plantarum LP-21; and Group M: Lactiplantibacillus plantarum, Enterococcus faecium, and Pediococcus pentosaceus). After 240 days of ensiling, the inoculated groups exhibited significantly higher contents of crude protein and dry matter (DM) and lower ammonia nitrogen, neutral detergent fiber, and acid detergent fiber levels than the control group. The M group demonstrated superior fermentation performance, exhibiting the lowest pH (C 5.15; B 4.77; P 4.64; and M 4.57), the highest lactic acid concentration (C 3.40% DM; B 6.80% DM; P 7.73% DM; and M 8.00% DM), and an optimal microbial composition dominated by Lactiplantibacillus and Lentilactobacillus. These improvements were attributed to Lactiplantibacillus plantarum, a bacterium that can produce a substantial amount of lactic acid through homofermentation, thereby lowering the pH, inhibiting the activity of undesirable microorganisms, and enhancing nutrient preservation. High-throughput sequencing revealed shifts in the dominant bacterial phyla from Proteobacteria in raw grass to Firmicutes in silage, with inoculants significantly influencing microbial diversity and functional profiles. Functional prediction indicated enhanced carbohydrate metabolism and nutrient preservation in the inoculated groups. These findings underscore the potential of tailored bacterial inoculants and advanced wrapping technology to improve the quality of silage and thus support sustainable livestock production.

Graphical Abstract

Background

Humic acids (HA) function as plant biostimulants, enhancing plant metabolism by activating the primary proton transport system, which promotes root growth. This study investigated the effects of HA on root growth, H⁺ extrusion, Ca²⁺ signaling, and reactive oxygen species (ROS) production, examining how HA might integrate nutrient sensing with growth regulation through plant hormone transport.

Results

HA rapidly increased cytosolic Ca²⁺ and ROS, and altered root architecture in Arabidopsis lines Columbia-0 (Col-0) and G548 TOROE (overexpressing TARGET OF RAPAMYCIN). In Col-0, HA exposure increased total, primary, and lateral root lengths, while in TOROE plants, only primary root length changed. HA also doubled the expression of transcripts in Col-0 roots, including those for PM H⁺-ATPase (AHA2), TOR kinase, ROS-related RBOHC, and auxin transporters LAX3 and PIN3. Only AHA2 and RBOHC were upregulated in TOROE plants. Findings indicate that HA promotes rhizosphere acidification and plasma membrane potential regulation via AHA2 and RBOHC, linked to auxin transporters and calcium signaling.

Conclusions

The data suggest HA, rich in compounds like quinones and flavonoids, stimulates root development by triggering Ca²⁺ waves, NADPH oxidase and H⁺-ATPase activities. These findings advance our understanding of TOR and H⁺-ATPase roles in root architecture.

Graphical abstract

As an edible algae with rich nutrients and high medicinal value, Durvillaea antarctica has certain potential in anti-aging, but there is currently limited research on the separation, purification and activity of its anti-aging active ingredients. We successfully extracted and purified a new β-(1,3)-D-glucan with a special branched structure from Durvillaea antarctica using subcritical water extraction combined with ultrafiltration membrane (SWE-UFM). The polysaccharide, named DAG-1, consists of glucose (92.70%) and has a weight-average molecular weight of 10149 Da. The GC–MS and 1D/2D NMR confirmed that DAG-1 was composed of 3)-β-D-Glcp-(1 → , → 3,6)-β-D-Glcp-(1 → , β-D-Glcp-(1 → and → 6)-α-D-Glcp-(1 → , and β-glycosidic linkages between these sugar units. Animal experiments showed that DAG-1 has significant anti-skin aging effects by inhibiting the reduction of superoxide dismutase (SOD) activity, accumulation of malonic dialdehyde (MDA), and decline in hydroxyproline (HYP) content in collagen fibers of D-gal-induced mouse skin. To further elucidate the mechanism of DAG-1, we found that DAG-1 can alleviate senescence in human dermal fibroblasts (HDFa), inhibit degranulation of human cutaneous mast cells (HCMC), and modulate inflammatory factors (TNF-α, IL-6) production. Additionally, DAG-1 may bind to c-KIT receptors and downregulate the expression of KITLG/KIT, regulating the growth and activation of mast cells, and thus alleviate skin aging. These findings suggest that DAG-1 is a potential anti-aging ingredient for functional food, cosmetic, and medicine development.

Graphical Abstract

Background

Melatonin is a crucial regulator of fruit growth and development. However, the mechanisms by which pre-harvest application of melatonin regulates the metabolism of phenolic compounds in pear pericarp remain poorly understood.

Methods

In this study, the effect of pre-harvest spraying of melatonin on the synthesis of phenolics in pear peel and the regulatory mechanism were investigated using a multi-disciplinary approach, integrating physiological and biochemical, transcriptomic, and metabolic analyses, and the “Yuluxiang” pear as the test material.

Results

The pre-harvest spraying of 100 μM melatonin notably increased the single fruit weight, total soluble solids (TSS) and total soluble solids/titratable acid (TSS/TA) ratio. In addition, the spraying regimen elevated the concentrations of phenolic substances, including anthocyanosides, chlorogenic acid, and lignin, in the fruit peel. Three comparison groups (T₀ vs. CK₀, T₁ vs. CK₁, and T₂ vs. CK₂) showed 354, 1385, and 816 differentially expressed genes (DEGs) and 240, 411, and 210 differentially expressed metabolites (DEMs), respectively. Transcriptome results from melatonin treatment significantly affected the key metabolic pathways, including signal transduction, hormone regulation, glucose metabolism, secondary metabolites biosynthesis, phenylpropanoid biosynthesis, and flavonoid biosynthesis. Melatonin treatment also influenced the expression of key genes in phenylpropanoid biosynthesis and flavonoid biosynthesis pathways, such as PAL, C4H, 4CL, CAD, CHS, UFGT, POD, and others. Metabolomic data suggested the melatonin treatment notably stimulated the biosynthesis of l-phenylalanine, cinnamic acid, caffeic acid, ferulic acid, leucocyanidin and uridine 5ʹ-diphospho-d-glucose than control. By examining the expression patterns of transcription factors, we identified 12 transcription factors (TFs), including PbrMYB4, PbrMYB36-like, PbrMYB14, PbrREF4 and PbrNAC6-like, as potential key TFs involved in melatonin-regulated polyphenol biosynthesis.

Conclusions

The pre-harvest application of 100 μM melatonin can help improve the visual and flavor quality of pear fruits. It can influence the key enzyme genes’ expression of phenolic metabolism while stimulating the production of l-phenylalanine, cinnamic acid, caffeic acid, ferulic acid, leucocyanidin and uridine 5ʹ-diphospho-d-glucose, which promote the biosynthesis of anthocyanidins, phenolic acids, and lignins. These findings provide comprehensive insights into the metabolic mechanisms of melatonin-regulated phenolic compounds in pear peels.

Graphical Abstract

Background

Powdery mildew poses a significant threat affecting goji plant cultivation, resulting in significant economic losses, particularly in low UV-B environments. To clarify the molecular mechanism by which UV-B-induced wax synthesis in leaves affects the resistance of goji powdery mildew, the ‘Ganqi II’ was used as the experimental material, natural light (no filtration, FUV-B) was used as the control, and two treatments were compared: polyethylene film filtration (filtering 48.62%, HUV-B) and glass filtration (filtering 98.33%, NUV-B). Differences in leaf wax load, powdery mildew resistance, and gene expression were analyzed under these treatments, and key genes involved in UV-B-induced wax synthesis were identified and validated through qRT-PCR, bioinformatics analysis, subcellular localization, and tobacco overexpression assays.

Results

The results showed that UV-B reduction using polyethylene film and glass decreased the leaf wax load from 90.65 µg/cm² to 70.53 µg/cm² and 49.99 µg/cm², respectively. Concurrently, the incidence of powdery mildew rose from 7.85 to 21.7% and 72.92%, while the disease index increased from 14.21 to 27.23 and 78.40, respectively. Transcriptomic data revealed that 122 differentially expressed genes (DEGs) were significantly enriched in the lipid metabolism pathway, with 26 DEGs specifically associated in the wax synthesis metabolic pathway. Under FUV-B conditions, the expression of LbCYP96A15 was 18.04 times higher than under NUV-B treatment. LbCYP96A15, localized in the endoplasmic reticulum, plays a key role in wax synthesis. Overexpression of LbCYP96A15 in tobacco increased wax load and reduced powdery mildew incidence and disease index compared to the wild type.

Conclusions

UV-B radiation enhances resistance to powdery mildew in goji plants by upregulating the expression of the LbCYP96A15 gene, which promotes leaf wax biosynthesis. LbCYP96A15, a key gene localized in the endoplasmic reticulum, plays a critical role in wax synthesis. Its overexpression significantly increases wax load and reduces the incidence of powdery mildew.

Graphical Abstract

Background

Serine acetyltransferase (SAT), an enzyme that catalyzes the formation of O-acetyl-serine (OAS), is integral to sulfur assimilation, cysteine (Cys) synthesis, and adventitious root development. However, it remains unclear how the SAT gene in Prunus persica regulates adventitious root (AR) formation.

Methods

Based on transcriptome data and SAT gene family identification, the physicochemical properties, evolutionary relationships, and cis-acting elements of the family genes were analyzed. Subsequently, the PpSAT1 gene was transformed into Prunus domestica and Arabidopsis thaliana by agrobacterium-mediated method to obtain the transgenic material, and its role in AR formation was characterized by a series of rooting index and enzyme activity experiments.

Results

In this study, based on transcriptome data, the cysteine metabolism pathway was significantly enriched during P. persica AR growth. After combining the FPKM value of transcriptome data with real-time fluorescence quantitative qRT-PCR, it was found that SAT1/4 showed high expression level, which may be a key gene in peach advection root growth. Based on this, SAT family members were identified from P. persica, and further shown by qRT-PCR, PpSAT1 gene exhibits a notable expression response during AR formation. Therefore, the PpSAT1 (Prupe.4G239400.1) gene was cloned from P. persica and performed genetic transformation on a related P. domestica as well as A. thaliana. The transgenic P. domestica and A. thaliana displayed more robust growth, and more developed root system compared to wild-type counterparts. In addition, peroxidase (POD) and superoxide dismutase (SOD) activities were also substantially elevated.

Conclusions

In summary, these findings suggest that PpSAT1 gene can facilitate AR development.

Graphical Abstract