Search Results (98)

The extraction technology of sterol was confirmed by ethanol reflux and saponification in this study. The orthogonal test was employed to assess the impact of extraction time, solid–liquid ratio, ethanol concentration and extraction temperature on the yield of sterol extraction. Hyperlipidemia model mice were established by feeding a high-fat and -sugar diet, and different doses of sterol extracts were given to the mice by gavages. The optimal extraction conditions were identified as an extraction time of 80 min, a solid–liquid ratio of 1:10, an ethanol concentration of 95%, and an extraction temperature of 90 °C, resulting in a sterol concentration of 1.16 mg/g. Compared with the high-fat model group, the high-dose group significantly reduced body weight by 17.2%, liver weight by 30.9%, and serum low density lipoprotein cholesterol by 20.0% (p < 0.05), while serum total cholesterol (5.59 ± 0.48 vs. 5.68 ± 0.64 mmol/L) and high-density lipoprotein cholesterol (0.98 ± 0.05 vs. 0.93 ± 0.03 mmol/L) showed no significant changes compared to the model group. Full article

The volatile organic compounds (VOCs) produced by K. cowanii Ch1 play a significant role in the inhibition of the mycelial growth of phytopathogen strains. As a continuation of our previous studies, we aim to elucidate the mechanisms of the responses of K. cowanii Ch1 against S. rolfsii during a colonization competence interaction in the presence and absence of a mixture of bacterial VOCs under in vitro conditions. The results of this study showed that, in the absence of bacterial VOCs, K. cowanii Ch1 cannot compete against S. rolfsii, and the RNA-Seq analysis revealed the differential expression of genes related to the oxidative stress response in K. cowanii Ch1 for survival. However, in the presence of bacterial VOCs, an interesting phenotypical response was observed in K. cowanii Ch1, resulting in the mycelial growth inhibition of S. rolfsii. The upregulated genes were related to the siderophore-mediated iron transport system, zinc ion transport system, antibiotic biosynthesis monooxygenase, carbohydrate metabolism, polyketide synthase modules, and related proteins, and katG was probably related to the phenotype resulting in the formation of gas bubbles by K. cowanii. In addition, the VOC profile analyzed at 36 h for bacterial growth revealed a cocktail with an ability to increase the competence of K. cowanii Ch1 against S. rolfsii in vitro and in vivo. This study provides evidence regarding the key role that VOCs play during the colonization competition involving K. cowanii Ch1, the comprehension of which may enable the development of new biocontrol strategies. Full article

Soil-borne fungal pathogens such as Sclerotium spp., Rhizoctonia spp., and Macrophomina spp. pose significant threats to global agriculture, with soybean crops among the most severely affected due to damping-off disease. These pathogens cause substantial yield losses, making their management a critical concern. In this study, we investigated the potential of Bacillus siamensis BCL, a novel Neotropical strain, as an eco-friendly solution for managing Sclerotium, Rhizoctonia, and Macrophomina species. The strain exhibited strong antifungal activity, significantly inhibiting fungal growth in vitro, with the greatest suppression observed against Macrophomina spp., reaching up to 81%. In vivo assays further confirmed the biocontrol potential of B. siamensis. When applied at 10⁶ colony-forming units (CFU)/mL, the strain reduced disease symptoms and improved plant growth parameters—including root length, shoot biomass, and leaf number—compared to untreated, infected controls. The protective effect varied by pathogen, with the most significant recovery in root length observed against Macrophomina spp. (85%) and Sclerotium spp. (78%). In preventive treatments, fermentation extracts of the B. siamensis strain suppressed disease progression, although they did not promote seedling growth. A genomic analysis of B. siamensis BCL revealed genes encoding antimicrobial secondary metabolites, including terpenes, fengycins, and surfactins. These findings highlight B. siamensis BCL as a promising candidate for sustainable crop protection and a valuable resource for developing novel antimicrobial strategies in agriculture. Full article

The cap-binding protein complex (CBC), comprising Cbp20 and Cbp80, is crucial for gene expression, yet its role in the notorious crop pathogen Botrytis cinerea remains unclear. Immunoprecipitation coupled with LC-MS/MS demonstrated that BcCbp20 interacts with BcCbp80. Yeast two-hybrid, GST pull-down, and Split-luciferase complementation assays confirmed that the conserved RNA recognition motif (RRM, 54–127 aa) of BcCbp20 and the N-terminal MIF4G domain (1–370 aa, 1–577 aa) of BcCbp80 constitute the core interaction regions. Genetic transformation experiments revealed that BcCBP80 exerts a more dominant role than BcCBP20 in regulating hyphal morphology, growth rate, conidiophore development, and conidial yield. Furthermore, BcCBP20 and BcCBP80 differentially regulate sclerotium formation to maintain sclerotial quantity. Based on pathogenicity assays, BcCBP80 associated with infection cushion development, with this phenotypic alteration possibly being among the factors correlated with altered pathogenicity. However, the increased sensitivity of ΔBccbp20 to various stress factors may be the primary reason for the diminished pathogenicity. Taken together, these results indicate that BcCBP20 and BcCBP80 play important roles in multiple aspects of B. cinerea growth, development, stress response, and pathogenicity. Full article

The NAC (NAM/ATAF1/2/CUC2) transcription factors are pivotal regulators in plant development and stress responses. Despite the extensive studies on the NAC gene family across various plant species, the characterization of this gene family in mulberry (Morus atropurpurea) remains unexplored. Here, we conducted a genome-wide identification and characterization of the NAC gene family in M. atropurpurea. A total of 79 MaNAC genes were identified and classified into 20 subgroups, displaying an uneven distribution across the 14 chromosomes. The structural analysis found that most MaNAC genes possess at least three exons and contain the conserved NAC domain and characteristic motifs at the N-terminus. Eleven collinear gene pairs were identified in M. atropurpurea genome. Interspecies collinearity analysis demonstrated a closer evolutionary relationship between M. atropurpurea and Populus trichocarpa, supported by the identification of 116 collinear gene pairs. Expression profiling revealed dynamic changes in the transcript levels of most MaNAC genes during mulberry fruit maturation. Notably, the eight MaNAC members from the OsNAC7 subfamily exhibited tissue-specific expression patterns. A significant proportion of MaNAC genes displayed varying degrees of responsiveness to drought stress and sclerotium disease. MaNAC12, MaNAC32, MaNAC44 and MaNAC67 emerged as the most highly responsive candidates. Overexpression of MaNAC69 enhanced drought tolerance in Arabidopsis. These findings provide a robust foundation for future functional studies and mechanistic investigations into the roles of the NAC gene family in M. atropurpurea, offering insights into their contributions to development and stress adaptation. Full article

Scleroglucan is the extracellular polysaccharide (EPS) produced by Sclerotium rolfsii (S. rolfsii). The low EPS titer and limited substrate utilization of S. rolfsii present significant challenges in the fermentation process, restricting industrial applications of scleroglucan. In this study, we performed a transcriptomic analysis on the mycelium of S. rolfsii fermented with different carbon sources. The key genes involved in polysaccharide biosynthesis (6-phosphofructokinase 1 (PFK1), pyruvate decarboxylase (PDC), aldehyde dehydrogenase (NAD (P)+) (ALDH3), and acetyl-CoA synthase (ACS)) were identified and their roles in the process were investigated. The supplementation of specific precursors—fructose-6-phosphate, pyruvate, aldehydes, and acetate—was shown to enhance both the polysaccharide titer and substrate utilization. By adding precursors, the titer of SEPS produced in a 5 L fermentation tank reached 48.69 ± 3.8 g/L. Notably, the addition of these precursors increased the titer of EPS fermented with sucrose (SEPS) by 65.63% and substrate utilization by 119.3%, while the titer of EPS fermented with lactose (LEPS) rose by 80.29% and substrate utilization rose by 47.08%. These findings suggest that precursor supplementation can effectively improve polysaccharide production and substrate efficiency, thereby minimizing resource waste and environmental impact. Full article

A total of 34 strains of bacteria were isolated from peanut rhizosphere soil, and all showed some in vitro inhibition of the pathogen Sclerotium rolfsii in co-culture. Strain YB-1632 produced the highest level of inhibition and also produced relatively high levels of biofilm in culture. Cell-free culture extracts and volatiles from it were also inhibitory to S. rolfsii. Based on 16S rDNA, gyrA, and gyrB sequences, it was identified as Bacillus siamensis. In the greenhouse, seed treatment resulted in a level of control of peanut sclerotium blight (PSB) comparable to that of a standard fungicide seed treatment. In addition to its antifungal activity, YB-1632 could induce disease resistance in peanut seedlings based on increasing peanut defense enzyme activities and gene expression. The priming of defense gene expression against a necrotrophic pathogen is consistent with Induced Systemic Resistance (ISR). In addition, YB-1632 produced enzyme activities in culture associated with root colonization and plant growth promotion. In the greenhouse, it increased peanut seedling growth, indicating the YB-1632 is a plant growth-promoting rhizobacterium (PGPR). In summary, YB-1632 is a promising novel PSB biocontrol agent and PGPR of peanut. Full article

Soil-borne diseases, including charcoal rot (Macrophomina phaseolina) and collar rot (Sclerotium rolfsii), threaten global soybean production. Four fungicide combinations were tested as seed treatments at three concentrations (1, 1.5, and 2 g or ml per kg of seed) under controlled conditions to address the challenges posed by these diseases. Under controlled conditions, the combination of thiophanate methyl + pyraclostrobin at a rate of 2 mL/kg of seed significantly alleviated disease symptoms caused by both pathogens. Additionally, it enhanced shoot and root weights by over 50% in plants affected by S. rolfsii. Field trials were conducted for two years at two distinct locations to assess the efficacy of three selected combination seed treatment fungicides against M. phaseolina and S. rolfsii. Both inoculated and uninoculated controls were included for the comparison. Among the fungicides, thiophanate-methyl + pyraclostrobin and trifloxystrobin + penflufen proved the most effective for suppressing both diseases under epiphytotic field conditions across the years and locations. This study also highlighted the benefits of these chemical combinations in enhancing agronomic traits, maintaining yield, and ensuring the economic viability of soybeans. Full article

The grey mould fungus Botrytis cinerea is a dangerous plant pathogen responsible for substantial agricultural losses worldwide. The pathogenic mechanisms still have many unclear aspects, and numerous new pathogenic genes remain to be identified. Here, we show that the sterol regulatory element-binding protein Sre1 plays an important role in the development and pathogenicity of B. cinerea. We identified a homologue of gene SRE1 in the B. cinerea genome and utilized a reverse genetics approach to create the knockout mutant Δsre1. Our results demonstrate that SRE1 is essential for conidiation, as Δsre1 produced only 3% of the conidia compared to the wild-type strain. Conversely, Δsre1 exhibited increased sclerotium production, indicating a negative regulatory role of SRE1 in sclerotium formation. Furthermore, ergosterol biosynthesis was significantly reduced in the Δsre1 mutant, correlating with increased sensitivity to low-oxygen conditions. Pathogenicity assays revealed that Δsre1 had significantly reduced virulence, although it maintained normal infection cushion formation and penetration capabilities. Additionally, SRE1 was found to be crucial for hypoxia adaptation, as Δsre1 showed abnormal germination and reduced growth under low-oxygen conditions. These findings suggest that SRE1 mediates the development and pathogenicity of B. cinerea by regulating lipid homeostasis and facilitating adaptation to host tissue environments. Full article

Polyporus umbellatus is a medicinal fungus primarily used for diuresis, with its sclerotium serving as the medicinal component. The growth and development of sclerotia are reliant on a symbiotic relationship with Armillaria. However, the impact of different Armillaria species on the yield and quality of sclerotia remains unclear. In this study, three Armillaria strains, A35, A541, and A19, were identified through TEF-1α sequence analysis and phylogenetic classification. These strains were classified into three distinct species: A35 as A. ostoyae, A541 as A. gallica, while the taxonomic status of A19 remains unresolved. After four years of co-cultivation with these Armillaria strains, three groups of P. umbellatus sclerotia were harvested and labeled as A35-P, A541-P, and A19-P, respectively. The yields of A35-P, A541-P, and A19-P exhibited significant variations, with A541-P achieving the highest yield (1221 ± 258 g·nest⁻¹), followed by A35-P (979 ± 201 g·nest⁻¹), and A19-P yielding the least (591 ± 54 g·nest⁻¹). HPLC revealed significant differences in the levels of polyporusterone A and polyporusterone B among the groups. The total polysaccharide content, determined via the phenol-sulfuric acid method, also varied significantly, with A541-P recording the highest content (0.897 ± 0.042%), followed by A19-P (0.686 ± 0.058%), and A35-P showing the lowest value (0.511 ± 0.083%). PCA based on these data indicated clear distinctions among A35-P, A541-P, and A19-P, with the three groups forming separate clusters. This study, for the first time, demonstrates the effects of three different Armillaria species on the yield and active compound content of P. umbellatus. These findings provide valuable insights for selecting high-quality Armillaria strains and offer guidance for the artificial cultivation of P. umbellatus. Full article

The grapevine (Vitis vinifera) is a major fruit crop of economic importance worldwide. Commercial grapevine cultivars are susceptible to infection by pathogenic microorganisms that cause diseases both in leaves and fruits, and it is known that the leaf microbiome plays an important role in plant health and fitness. In this study, shotgun metagenomic sequencing was used to characterize the microbial communities associated with grapevine leaves in three commercial varieties, Cabernet Sauvignon, Garnacha, and Marselan, grown in the same biogeographical unit. Metagenomic data revealed a differential enrichment of the microbial communities living inside grapevine leaves or on the leaf surface in the three varieties. The most abundant fungal taxa associated with grapevine leaves belong to the phylum Ascomycota, which included relevant pathogenic fungi for grapevines, such as Botrytis cinerea, Sclerotinia sclerotium, and Alternaria alternata, as well as several fungal species potentially pathogenic for grapevines (e.g., members of the Colletotrichum, Aspergillus, and Penicillium genera). Basidiomycota constituted a minor fraction of the fungal microbial communities. Grapevine leaves also harbored a diversity of bacterial taxa. At the phylum level, bacterial communities in all three varieties were primarily composed of Pseudomonadata, Bacillota, Bacteroidota, and a lower proportion of Actinomycetota. Differences in the fungal and bacterial community structures were observed between varieties, although they were more important in fungi. In particular, S. sclerotiorum and B. cinerea were found to preferentially colonize leaves in the Marselan and Garnacha varieties, respectively. These findings further support that the host genotype can shape its own microbiome in grapevines. A better understanding of the leaf microbiome in grapevines will provide the basis for the development of tailored strategies to prevent diseases in vineyards while helping to increase sustainability in grapevine production. Full article

In the industrial production of Lentinula edodes and Pleurotus eryngii, slow growth of the mother seed and insufficient hyphal vitality can significantly affect the cultivation process. To shorten the growth period on traditional PDA medium, two strains of L. edodes and P. eryngii were cultured with different proportions of P. tuber-regium and Wolfiporia hoelen sclerotium powders added into the medium to investigate the effect on the mycelial growth. Compared to the PDA, the addition of sclerotia powder significantly enhanced the growth of mycelia, with an optimal addition ratio of 2%. Transcriptome sequencing was performed after culturing L. edodes and P. eryngii on PDA, PDA with 2% P. tuber-regium sclerotium powder, and PDA with 2% W. hoelen sclerotium powder. GO enrichment analysis of the differentially expressed genes (DEGs) of L. edodes and P. eryngii strains cultured in the sclerotia powder media showed significant changes in oxidoreductase and glucosidase activities. Changes were observed in KEGG annotation for carbohydrate metabolism, glycolysis, pyruvate metabolism, and other energy metabolic pathways. Moreover, carbohydrate-active enzyme (CAZyme) family genes were predominantly upregulated. The increase in the activity of CAZyme and oxidoreductases promotes the degradation of nutrients in the sclerotia into small-molecule substances, which explains why the sclerotia powder culture medium promotes mycelial growth. Full article

In this study, seed-surface-associated bacteria from fresh fruits of Capsicum spp. were analyzed to explore potential isolates for biocontrol of phytopathogenic fungal strains. A total of 76 bacterial isolates were obtained from three different species of chili pepper (C. annuum L., C. pubescens R. & P., and C. chinense Jacq.), and two isolates were selected via mycelial growth inhibition assays based on their production of volatile organic compounds (VOCs) against six fungal strains. Genomic analysis identified these isolates as Bacillus altitudinis CH05, with a chromosome size of 3,687,823 bp and with 41.25% G+C, and Bacillus tropicus CH13, with a chromosome size of 5,283,706 bp and with 35.24% G+C. Both bacterial strains showed high mycelial growth inhibition capacities against Sclerotium rolfsii, Sclerotinia sp., Rhizoctonia solani, and Alternaria alternata but lower inhibition capacities against Colletotrichum gloesporoides and Fusarium oxysporum. VOC identification was carried out after 24 h of fermentation with 64 VOCs for B. altitudinis CH05 and 53 VOCs for B. tropicus CH13. 2,5-Dimethyl pyrazine and acetoin had the highest relative abundance values in both bacterial strains. Our findings revealed that seed-surface-associated bacteria on Capsicum spp. have the metabolic ability to produce VOCs for biocontrol of fungal strains and have the potential to be used in sustainable agriculture. Full article

The objective of this study was to identify effective agents for the prevention and control of ginseng Sclerotinia root rot disease caused by Sclerotinia nivalis. The inhibitory effects of 16 chemical fungicides and 10 biocontrol agents (strains) on mycelial growth and sclerotium formation in S. nivalis were determined using a plate confrontation essay. The results showed that the best chemical agents for inhibiting the mycelial growth and sclerotium formation of S. nivalis were fluconazole and fludioxonil, while Bacillus amyloliquefaciens FS6 and B. subtilis (Kono) were the best biocontrol agents (strains). The results of field trials in 2022 and 2023 showed that the control effects of fluconazole and fludioxonil on ginseng Sclerotinia root rot disease were 90.60–98.16%, and those of the biocontrol agents B. amyloliquefaciens FS6 and B. subtilis (Kono) were 94.80–97.24%, respectively. Chemical agents produced abnormal and twisted mycelia, while the biocontrol agents increased mycelial branching, dilated the mycelium tip, and revealed an abnormal balloon. All of the fungicides decreased the ergosterol content, changed the cell membrane permeability, and increased the protein and nucleic acid permeability. These results suggest that these are potential agents for controlling ginseng Sclerotinia root rot disease, and their biochemical mechanisms of chemical and biocontrol of this disease were demonstrated. Full article

Edamame (Glycine max (L.) Merr.) is a specialty soybean newly grown in the United States that has become the second most widely consumed soy food (25,000–30,000 tons annually). Poor crop establishment caused by soilborne diseases is a major problem limiting edamame production in the U.S. This study investigated 24 edamame cultivars/lines to determine their response to three soilborne pathogens causing seed rot and seedling damping off, including Rhizoctonia solani, Sclerotium rolfsii, Pythium irregulare, and Xanthomonas campestris pv. glycines, a seedborne pathogen that caused severe outbreaks of bacterial leaf pustules in mid-Atlantic regions in 2021. The hypothesis was that resistant variations existed among the genotypes, which could be used for production and future breeding efforts. The results reveal that all genotypes were affected, but partially resistant varieties could be clearly recognized by a significantly lower disease index (p < 0.05), and no genotype was resistant to all four diseases. Newly developed breeding lines showed overall higher disease resistance than commercial cultivars, particularly to R. solani and P. irregulare. This study found genetic variability in edamame, which can be helpful in breeding for resistance or tolerance to early-season diseases. The result will promote domestic edamame production and further strengthen and diversify agricultural economies in the U.S. Full article