Search Results (618)

Fusarium verticillioides, an important global pathogenic fungus, compromises crop quality and yield by infecting maize, sugarcane, and some Solanaceae, endangering food security through contaminated grains and cereals with the fumonisin B1 (FB1) toxin. While Con7 has been reported as a transcription factor involved in the sporulation and pathogenicity of some pathogenic fungi, the function of FvCon7 and its regulatory genes in F. verticillioides remains uncharacterized. Gene deletion mutants of ΔFvcon7 were constructed through homologous recombination, which exhibited defects in vegetative growth, survival, sporophore development, conidiation, conidial germination, and carbon metabolism. Carbon metabolism defects led to a significant accumulation of glycogen granules in hypha and lipid bodies in conidia. Additionally, ΔFvcon7 displayed impaired cell wall structure and integrity, along with an altered expression of genes encoding cell wall-degrading enzymes (such as chitinase), as detected by qRT-PCR. Moreover, Fvcon7 also plays a role in the pathogenicity of maize and sugarcane through different splicing, defective conidia, reduced survival viability, differential expression of secreted proteins, and deficiencies in antioxidant stress capacity. Furthermore, using yeast one-hybrid (Y1H) assays, FvCon7 was found for the first time to directly regulate the expression of FvFUMs by binding to the CCAAT box within the promoters of six key FvFUMs, thereby affecting FB1 production. Overall, FvCon7 functions as a global transcription factor regulating multiple phenotypes. This study provides a theoretical basis for elucidating the mechanism of transcription factor FvCon7 regulating toxin production and pathogenesis in F. verticillioides. Full article

Ganoderic acid (GA) is a key bioactive component with pharmacological properties that is found in Ganoderma lingzhi, a renowned medicinal mushroom. Currently, the regulatory mechanisms underlying GA biosynthesis in G. lingzhi remain to be further elucidated. In this study, blue light induction was found to significantly enhance the GA content in G. lingzhi. To explore the regulatory mechanism of GA biosynthesis in response to blue light, the blue light receptor WC-2 was identified, and its regulatory role was characterized. The deletion of wc-2 resulted in a significant reduction in both GA content and the accumulation of intermediates compared to the wild-type control strain, largely due to the strong downregulation of key GA biosynthetic genes. Additionally, decreased asexual spore production and reduced expression of sporulation-specific genes were observed with the deletion of wc-2. The overexpression of wc-2 led to greatly enhanced GA accumulation. Under blue light induction, the maximum contents of GA-Mk, GA-T, GA-S, and GA-Me were 2.27-, 2.51-, 2.49-, and 2.08-fold higher, respectively, compared to the control kept in darkness. These results demonstrate that the blue light receptor WC-2 functions as a positive regulator of GA biosynthesis in G. lingzhi, influencing the expression of genes involved in GA biosynthesis and asexual spore production, thereby advancing our understanding of the intricate regulatory network of GA biosynthesis. Full article

Four Botryosphaeria spp. isolated from apple with dieback symptoms, Diplodia mutila, Diplodia seriata, Neofusicoccum arbuti, and Lasiodiplodia theobromae, were subjected to different conditions to induce sporulation, then freeze-dried and stored in glass vials and ampoules at a temperature of 4 ° C using two protective media (skimmed milk powder in water at 20% and a mixture of skimmed milk powder at 20% plus 5% inositol). Viability was assessed after storage periods of 1, 90, 180, and 365 days. Low-nutrient growth conditions on 2% water agar supplemented with pine needles, incubated under UV light (λ = 350 nm) and at 24 ° C, effectively stimulated sporulation of all four Botryosphaeriaceae species. The survival rate of the isolates was similar. Overall viability showed slight but significant differences depending on the type of protective medium and storage container used for the freeze-dried cultures (p < 0.001). Among the tested media, the highest viability was maintained in vacuum-sealed glass ampoules using either a medium containing 20% skimmed milk powder with 5% inositol or 20% skimmed milk powder alone. Full article

Alcohol abuse and alcoholic liver diseases (ALD) are globally prevalent, with alcohol-induced gut microbiota dysbiosis playing a key role in ALD pathogenesis. Synbiotic (combinations of probiotics and prebiotics) are recognized as effective in reducing inflammation in ALD. Bacillus coagulans, a probiotic with favorable industrial and functional traits (e.g., sporulation, lactic acid production), shows potential in treating intestinal diseases. Here, we investigated the effects of B. coagulans, alone or combined with pectin, on ethanol-induced ALD in mice. Synbiotic supplementation (B. coagulans + pectin) more significantly alleviated ethanol-induced ALD severity than B. coagulans or pectin alone. Relative to the ethanol group, synbiotic treatment significantly reduced hepatic inflammatory injury and lipid accumulation, downregulated proinflammatory factors (TNF-α, IL-1β, myeloperoxidase [MPO]), and upregulated tight junction proteins and mucins—enhancing intestinal barrier function. Moreover, these supplements modulated gut microbiota composition and enhanced short-chain fatty acids (SCFAs) production by increasing the abundance of beneficial SCFA-producing bacteria (Muribaculaceae, Akkermansia). In summary, changes in tight junction proteins, cytokines and hepatic injury markers indicate that the synbiotic alleviated overall inflammation in the experimental ALD model and exerted a greater therapeutic effect than B. coagulans or pectin alone. Full article

Talaromyces pinophilus is a filamentous fungus with notable lignocellulose-degrading capacity based on enzyme activities and protein secretion potential, making it a compelling candidate for industrial biotechnology applications. In this study, we present the genomic characterization of the highly cellulolytic strain Y117, a domesticated variant of T. pinophilus, based on whole-genome sequencing and comparative genomic analysis with eleven related strains. Comprehensive analysis of CAZymes, transcription factors, and secondary metabolite diversity in T. pinophilus strains revealed that the exceptional lignocellulose degradation capacity of Y117 is driven by its unique genomic architecture. Key genomic features that distinguish Y117 include (1) significant expansion of glycoside hydrolase (GH) and carbohydrate-binding module (CBM) families, (2) loss of fungal-RiPP-like clusters, and (3) absence of the developmental regulator BrlA. These genomic adaptations could indicate a metabolic trade-off favoring hydrolytic enzyme production over secondary metabolism and sporulation. Our findings provide fundamental insights into fungal lignocellulose degradation mechanisms while establishing Y117 as a promising chassis for metabolic engineering applications in industrial enzyme production and heterologous protein expression. Full article

Platycerium bifurcatum is one of the most widely cultivated ornamental fern species worldwide and a valuable component of the biodiversity of pantropical forests. In addition to its photosynthetic function, the sporotrophophyll leaves of this species periodically develop a large, clearly demarcated sporangium at the leaf tips, enabling physiological and biochemical measurements both in the active sporulation part and in the non-sporulating leaf area. The aim of this study was to assess anatomical changes, determine thermal effects and the content of selected phytohormones, and analyze the spatial distribution of pigments in the sporophilic and trophophylic part of the same leaf during spore formation. The study utilized fluorescence microscopy, isothermal microcalorimetry, Raman mapping, and ultra-high-performance liquid chromatography coupled with a Triple Quad LC/MS analyzer. The results revealed significant physiological differences between the sporulating and non-sporulating leaf areas. For the first time, differences in thermogenesis within the two leaf regions accompanying sporulation and linked to the sporangium development stage have been demonstrated in ferns. Increases in gibberellins (GA3, GA4, and GA6), auxin (indole-3-butyric acid), (±)-cis, trans-abscisic acid, and abscisic acid glucose ester were observed in the sporophilic part of the leaf, as well as fluctuations in phytohormones in the trophophilic part, indicating internal metabolite relocation within the leaf. Raman analysis and 2D mapping revealed local lignin accumulation and fluctuations in carotenoid levels during spore maturation. The results of this study demonstrate physiological variation within a single leaf and the mechanisms accompanying sporulation, which provide a better understanding of fern adaptive strategies. Full article

Histone tail phosphorylation has diverse effects on a myriad of cellular processes, including cell division, and is highly conserved throughout eukaryotes. Histone H3 phosphorylation at threonine 3 (H3T3) during mitosis occurs at the inner centromeres and is required for proper biorientation of chromosomes on the mitotic spindle. While H3T3 is also phosphorylated during meiosis, a possible role for this modification has not been tested. Here, we asked if H3T3 phosphorylation is important for meiotic division by quantifying sporulation efficiency and spore viability in Saccharomyces cerevisiae mutants with a T3A amino acid substitution. The T3A substitution resulted in reduced sporulation efficiency and reduced spore viability. Analysis of two other H3 tail mutants, K4A and S10A, revealed different effects on sporulation efficiency and spore viability compared to the T3A mutant, suggesting that these phenotypes may be due to failures in distinct functions. To determine if the spindle checkpoint promotes spore viability of the T3A mutant, the MAD2 gene was deleted. This resulted in a severe reduction in spore viability following meiosis. Altogether, the data reveal an important function for histone H3 threonine 3 that requires monitoring by the spindle checkpoint to ensure successful completion of meiosis. Full article

Chk1, a highly conserved serine/threonine protein kinase, functions as a critical regulator of fungal cell cycle progression, mitotic fidelity, and DNA damage response. In this study, we characterized an orthologous Chk1 (AoChk1) in a ubiquitous nematode-trapping fungus, Arthrobotrys oligospora, through targeted gene knockout coupled with integrated phenotypic, metabolomic, and transcriptomic analyses. This study aims to elucidate the function and potential regulatory networks of AoChk1 in A. oligospora. Deletion of Aochk1 leads to significant reductions in nucleus number, hyphal cell length, conidial production, and trap formation, but an increase in the accumulation of lipid droplets and autophagy. In addition, transcriptomics data indicate that AoChk1 plays an important role in cell cycle and division, nuclear architecture and organelle dynamics, protein homeostasis maintenance, and membrane systems. In addition, the inactivation of the Aochk1 exhibited remarkably reduced metabolite abundance relative to the WT strain. In conclusion, our results identify AoChk1 as an important regulator of asexual development, pathogenicity, and metabolic processes in A. oligospora. Full article

(1) Background: Tolypocladium spp. are fungi known for producing cyclosporin A and their ability to infect insects. However, their pathogenicity against the lepidopteran pest Plutella xylostella has not been previously reported. (2) Methods: Four Tolypocladium strains were isolated from soil and identified through morphological and phylogenetic analyses (ITS, gene sequencing). Growth rates, sporulation capacity, and stress tolerance (45 °C heat, UV) were evaluated. Pathogenicity was assessed via larval bioassays, and immune responses were analyzed by quantifying Toll pathway gene expression and enzyme activities (PO, CAT, POD, GSTs, CarE, AChE) from 24 to 96 h post-inoculation. (3) Results: Strains N8-SF-04092 and O1/O2/O3-SF-04630/04927/04931 were identified as Tolypocladium cylindrosporum and Tolypocladium inflatum, respectively. Strain O2 showed the highest growth rate (p < 0.05), while O3 and N8 exhibited superior sporulation (>7 × 10⁵ spores/mm²). N8 also demonstrated notable thermotolerance. In pathogenicity assays, O1, O3, and N8 caused 98.3%, 93.3%, and 96.7% larval mortality, respectively, with LT₅₀ values (3.89–4.45 days) significantly lower than O2 (p < 0.05). Immune gene expression in P. xylostella was transiently activated at 24 h but suppressed from 48 to 96 h by N8 (p < 0.05), while O1 induced partial activation at 24 h and 96 h but suppression at 48 h and 72 h. Protective enzymes (PO, CAT) were initially upregulated (24–48 h) but inhibited after 72 h (p < 0.01). POD activity showed opposing trends between O1 (initially activated then suppressed) and N8 (initially suppressed then activated). Detoxification enzymes (GSTs, CarE, AchE) were predominantly suppressed, except for GSTs, which increased at 72–96 h. (4) Conclusions: Strains O1 and N8 exhibit high virulence against P. xylostella by disrupting immune responses through dynamic modulation of Toll pathway genes and enzyme activities. The thermotolerance of strain N8 further enhances its promising biocontrol agent for field application. Full article

Blue mold of pome fruit, caused by Penicillium expansum, is controlled through postharvest applications of thiabendazole (TBZ), pyrimethanil (PYR), and fludioxonil (FDL). However, multi-fungicide-resistant isolates have emerged in the U.S. Pacific Northwest and their impact on decay control in long-term storage is unknown. This study evaluated the fitness of P. expansum isolates sensitive to all three postharvest fungicides (wild-types) and those resistant to TBZ (single-resistant), TBZ and PYR, or PYR and FDL (dual-resistant), and triple-resistant to the three fungicides. On nutrient-poor media, resistant isolates showed reduced conidial germination, whereas no significant differences were observed in germination, mycelial growth, or sporulation between phenotypes on nutrient-rich media at 1.5 and 20 °C. Regardless of their sensitivity phenotype, FDL-resistant isolates showed increased sensitivity to osmotic and oxidative stresses. Pathogenicity and virulence were not affected by the sensitivity phenotype on apples after six months of storage at 1.5 °C. Analysis of cumulative fitness changes indicated fitness loss under low-temperature in vitro and increased fitness under fungicide selection pressure on fruit in most resistant phenotypes. Gene expression analysis showed differential regulation of fitness-related genes, with most being up-regulated by TBZ. Overall, the results suggest that resistance in P. expansum may carry context-dependent fitness penalties, especially under high-stress conditions. Full article

Entomopathogenic fungi (EPF) are one of the most environmentally friendly ways to control a plethora of chewing insects such as T. pityocampa, G. mellonella, and A. grisella. Bioassay of EPF on these highly damaging pests is considered important in the face of climate change in order to research alternative solutions that are capable of limiting chemical control, the overuse of which increases insects’ resistance to chemical compounds. In this study, the insecticidal virulence of Metarhizium robertsii isolates, retrieved from forest ecosystems, was tested on second-instar larvae of T. pityocampa, G. mellonella, and A. grisella. Bioassays were carried out in the laboratory, where experimental larvae were sprayed with 2 mL of a six-conidial suspension from each isolate. Mortality was recorded for 144 h after exposure. Mean mortality, lethal concentrations, sporulation percentage, and sporulation time were estimated for each isolate. Metarhizium isolates resulted in the highest mortality (89.2% for G. mellonella and 90.2% for A. grisella). Based on the LC₅₀ estimates determined by the concentration–mortality relationships for the tested fungal isolates, we demonstrated significant virulence on larvae of G. mellonella, A. grisella, and T. pityocampa. Our results indicate that entomopathogenic fungi have the potential to become a very useful tool in reducing chemical applications. Full article

Foodborne illness caused by bacterial pathogens is a global health concern and results in millions of infections annually. Therefore, food products typically undergo several processing stages, including sanitation steps, before being distributed in an attempt to remove pathogens. However, many sanitation methods have compounding effects on the color, texture, flavor, and nutritional quality of the product or do not effectively reduce the pathogens that food can be exposed to. Some bacterial pathogens particularly possess traits and tactics that make them even more difficult to mitigate such as biofilm formation. Non-thermal plasma sanitation techniques, including plasma-treated water (PTW), have proven to be promising methods that significantly reduce pathogenic bacteria that food is exposed to. Published work reveals that PTW can effectively mitigate both gram-positive and gram-negative bacterial biofilms. This study presents a novel analysis of the differences in antimicrobial effects of PTW treatment between biofilm-forming gram-positive bacteria, commonly associated with foodborne illness, that are sporulating (Bacillus cereus) and non-sporulating (Listeria monocytogenes). After treatment with PTW, the results suggest the following hypotheses: (1) that the non-sporulating species experiences less membrane damage but a greater reduction in metabolic activity, leading to a possible viable but non-culturable (VBNC) state, and (2) that the sporulating species undergoes spore formation, which may subsequently convert into vegetative cells over time. PTW treatment on gram-positive bacterial biofilms that persist in food processing environments proves to be effective in reducing the proliferating abilities of the bacteria. However, the variance in PTW’s effects on metabolic activity and cell vitality between sporulating and non-sporulating species suggest that other survival tactics might be induced. This analysis further informs the application of PTW in food processing as an effective sanitation method. Full article

In chili cultivation, obstacles to continuous cropping significantly compromise crop yield and soil health, whereas crop rotation can enhance the microbial environment of the soil and reduce disease incidence. However, its effects on the diversity of rhizosphere soil microbial communities are not clear. In this study, we analyzed the composition and characteristics of rhizosphere soil microbial communities under chili continuous cropping (CC) and chili–cotton crop rotation (CR) using high-throughput sequencing technology. CR treatment reduced the alpha diversity indices (including Chao1, Observed_species, and Shannon index) of bacterial communities and had less of an effect on fungal community diversity. Principal component analysis (PCA) revealed distinct compositional differences in bacterial and fungal communities between the treatments. Compared with CC, CR treatment has altered the structure of the soil microbial community. In terms of bacterial communities, the relative abundance of Firmicutes increased from 12.89% to 17.97%, while the Proteobacteria increased by 6.8%. At the genus level, CR treatment significantly enriched beneficial genera such as RB41 (8.19%), Lactobacillus (4.56%), and Bacillus (1.50%) (p < 0.05). In contrast, the relative abundances of Alternaria and Fusarium in the fungal community decreased by 6.62% and 5.34%, respectively (p < 0.05). Venn diagrams and linear discriminant effect size analysis (LEfSe) further indicated that CR facilitated the enrichment of beneficial bacteria, such as Bacillus, whereas CC favored enrichment of pathogens, such as Firmicutes. Fusarium solani MG6 and F. oxysporum LG2 are the primary chili root-rot pathogens. Optimal growth occurs at 25 °C, pH 6: after 5 days, MG6 colonies reach 6.42 ± 0.04 cm, and LG2 5.33 ± 0.02 cm, peaking in sporulation (p < 0.05). In addition, there are significant differences in the utilization spectra of carbon and nitrogen sources between the two strains of fungi, suggesting their different ecological adaptability. Integrated analyses revealed that CR enhanced soil health and reduced the root rot incidence by optimizing the structure of soil microbial communities, increasing the proportion of beneficial bacteria, and suppressing pathogens, providing a scientific basis for microbial-based soil management strategies in chili cultivation. Full article

The transition from conchocelis to conchosporangia in Pyropia haitanensis represents a pivotal stage in its life cycle. As a commercially vital red alga, P. haitanensis plays a dominant role in global nori production. The transition governing its sporulation efficiency is pivotal for aquaculture success, yet the underlying regulatory mechanisms, especially their integration with metabolic cues such as polyamines, remain poorly understood. This study uncovered a critical role for the polyamine spermine (SPM) in promoting conchosporangial formation, mediated through the signaling activity of superoxide anions (O₂·⁻). Treatment with SPM markedly elevated O₂·⁻ levels, an effect that was effectively inhibited by the NADPH oxidase inhibitor diphenyliodonium chloride (DPI), underscoring the role of O₂·⁻ as a key signaling molecule. Transcriptomic analysis revealed that SPM enhanced photosynthesis, carbon assimilation, and respiratory metabolism, while simultaneously activating antioxidant enzymes, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), to regulate hydrogen peroxide (H₂O₂) levels and maintain redox homeostasis. Furthermore, SPM upregulated genes associated with photosynthetic carbon fixation and the C₂ oxidative photorespiration pathway, supplying the energy and metabolic resources necessary for this developmental transition. These findings suggested that SPM orchestrated O₂·⁻ signaling, photosynthetic activity, and antioxidant defenses to facilitate the transition from conchocelis to conchosporangia in P. haitanensis. Full article

This research analyzes the innovative development of carnauba wax coatings enriched with essential oils (EOs: lemon, orange, grapefruit, clove, oregano, and cinnamon) or fruit by-products (FBPs: avocado, tomato, carrot, orange, lemon, and grapefruit) to improve postharvest preservation of organic oranges and lemons. Six EOs and six FBPs were evaluated for total phenolic content (TPC) and in vitro antifungal activity against Penicillium digitatum. Based on results, grapefruit, oregano, and clove EOs were selected for lemons, while avocado, orange, and grapefruit FBPs were selected for oranges. An in vivo test at 20 °C for 15 days with carnauba wax coatings assessed antifungal performance. Clove EO and avocado FBP showed strong in vitro inhibition and consistent hyphal suppression (~100 and ~82%, respectively). In vivo, coatings with grapefruit EO and avocado FBP significantly reduced fungal decay and sporulation (~75%) in lemons and oranges, respectively. Coated fruits also retained weight losses by ~25% compared to uncoated ones. These findings suggest that phenolic-rich natural extracts, especially from agro-industrial residues like avocado peels, offer a promising and sustainable strategy for postharvest citrus disease control. Further studies should test coating effectiveness in large-scale trials under refrigeration combined with other preservation strategies. Full article