Search Results (87)

The interaction between bacteria and fungi is one of the key interactions of microbial ecology, including mutualism, antagonism, and competition, which profoundly affects the balance and functions of animal microbial ecosystems. This article reviews the interactive dynamics of bacteria and fungi in more concerned microenvironments in animals, such as gut, rumen, and skin. Moreover, we summarize the molecular mechanisms and ecological functions of the interaction between bacteria and fungi. Three major bacterial–fungal interactions (mutualism, antagonism, and competition) are deeply discussed. Understanding of the interactions between bacteria and fungi allows us to understand, modulate, and maintain the community structure and functions. Furthermore, this summarization will provide a comprehensive perspective on animal production and veterinary medicine, as well as guide future research directions. Full article

Restricting the use of chemical pesticides in forestry requires the search for alternative solutions. These could be volatile organic compounds produced by three investigated species of bacteria (Bacillus amyloliquefaciens (ex Fukumoto) Priest, B. subtilis (Ehrenberg) Cohn and B. thuringiensis Berliner), which inhibit the growth of the pathogen F. oxysporum Schltdl. emend. Snyder & Hansen in forest nurseries. The highest inhibition of fungal growth (70%) was observed with B. amyloliquefaciens after 24 h of antagonism test, which had a higher content of carbonyl compounds (46.83 ± 8.41%) than B. subtilis (41.50 ± 6.45%) or B. thuringiensis (34.62 ± 4.77%). Only in the volatile emissions of B. amyloliquefaciens were 3-hydroxybutan-2-one, undecan-2-one, dodecan-5-one and tetradecan-5-one found. In contrast, the main components of the volatile emissions of F. oxysporum were chlorinated derivatives of benzaldehyde (e.g., 3,5-dichloro-4-methoxybenzaldehyde) and chlorinated derivatives of benzene (e.g., 1,4-dichloro-2,5-dimethoxybenzene), as well as carbonyl compounds (e.g., benzaldehyde) and alcohols (e.g., benzyl alcohol). Further compounds were found in the interactions between B. amyloliquefaciens and F. oxysporum (e.g., $\alpha$-cubebene, linalool, undecan-2-ol, decan-2-one and 2,6-dichloroanisole). Specific substances were found for B. amyloliquefaciens (limonene, nonan-2-ol, phenethyl alcohol, heptan-2-one and tridecan-2-one) and for F. oxysporum (propan-1-ol, propan-2-ol, heptan-2-one and tridecan-2-one). The amounts of volatile chemical compounds found in B. amyloliquefaciens or in the bacterium–fungus interaction can be used for further research to limit the pathogenic fungus. In the future, one should focus on the compounds that were found exclusively in interactions and whose content was higher than in isolated bacteria. In order to conquer an ecological niche, bacteria increase the production of secondary metabolites, including specific chemical compounds. The results presented are a prerequisite for creating an alternative solution or supplementing the currently used methods of plant protection against F. oxysporum. Understanding and applying the volatile organic compounds produced by bacteria can complement chemical plant protection against the pathogen, especially in greenhouses or tunnels where plants grow in conditions that favour fungal growth. Full article

Fruit rot seriously damages pomelo production. Given concerns regarding the safety of chemical agents, biological alternatives are becoming more preferable. Therefore, the experiment aimed to (i) identify the pathogens causing pomelo fruit rot disease and (ii) select Trichoderma spp. strains controlling the determined pathogens in Ben Tre, Vietnam. Three pathogenic fungal strains isolated from diseased pomelo fruits were selected. The three pathogenic fungal strains were randomly injected into 9 healthy pomelo fruits. The strain PCP-B02-A2 led to a completely rotten fruit on day 17 after infection, while strains PCP-B02-B2 and PCP-B03-A1 had infected spots whose lengths were 17.5 and 28.1 mm, became larger, and eventually led to the whole fruit rot. The pathogens were identified by the internal transcribed spacer (ITS) technique as Colletotrichum gloeosporioides PCP-B02-A2, Pseudopestalotiopsis camelliae sinensis PCP-B03-A1, and P. chinensis PCP-B02-B2. Twenty-five Trichoderma spp. strains were isolated. The ITS technique identified four strains, including Trichoderma asperellum TP-B01, T. harzianum TP-B08, T. harzianum TP-B09, and T. asperellum TP-C25. The PCP-B02-A2 strain had antagonism at 66.7–68.7%, while those of PCP-B02-B2 and PCP-B03-A1 were 64.2–71.1% and 55.7–57.4%, respectively. Full article

Root-knot nematodes (RKNs; Meloidogyne incognita) pose a significant threat to tomato crops, necessitating sustainable control methods. This study investigated the inoculation efficacy of co-cultured Burkholderia vietnamiensis B418 and Trichoderma harzianum T11W compared with single-strain treatments for RKNs suppression and their influence on the structure and function of the rhizosphere microbiome. Co-inoculation with B418 + T11W achieved a 71.42% reduction in the disease index, significantly outperforming single inoculations of B418 (54.46%) and T11W (58.93%). Co-inoculation also increased plant height by 38.51% and fresh weight by 76.02% compared to the RKNs infested plants control, promoting robust tomato growth. Metagenomic analysis reveals that co-inoculation enhanced bacterial diversity, with 378 unique bacterial species and a high Shannon index, while fungal diversity decreased with Trichoderma dominance (83.31% abundance). Actinomycetota (46.42%) and Ascomycota (97.92%) were enriched in the co-inoculated rhizosphere, showing negative correlations with RKNs severity. Functional analysis indicates enriched metabolic pathways, including streptomycin and unsaturated fatty acid biosynthesis, enhancing microbial antagonism. Single inoculations altered pathways like steroid degradation (B418) and terpenoid biosynthesis (T11W), but co-inoculation uniquely optimized the rhizosphere microenvironment. These findings highlight co-inoculation with B418 + T11W effectively suppressing RKNs and fostering plant health by reshaping microbial communities and functions, offering a promising approach for sustainable agriculture. Full article

As significant fungal pathogens of crops, Fusaria species contaminate various food and feed commodities. Some of the Fusarium spp. secondary metabolites (e.g., trichothecenes, zearalenone, and fumonisins) are widely known toxic molecules (mycotoxins) with chronic and acute effects on humans and animals. The growing demand for safer, pesticide-free food drives us to increase biological control during crop growing. Recent research suggests that lactic acid bacteria (LABs) as biocontrol are the best choice for extenuating Fusarium mycotoxins. Newly isolated LABs were tested as antifungal agents against Fusarium verticillioides, F. graminearum, and F. oxysporum. The characterized and genetically identified LABs belonged to Limosilactobacillus fermentum (SD4) and Lactiplantibacillus plantarum (FCW4 and CB2) species. All tested LABs and their cell-free culture supernatants showed antagonism on the MRS solid medium. The antifungal activity was also demonstrated on surface-sterilized wheat and peanuts. The germination test of corn kernels proved that the LAB strains SD4 and FCW4 significantly (p < 0.05) enhanced root and shoot development in plantlets while simultaneously suppressing the outgrowth of F. verticillioides. Small-scale corn silage fermentation revealed the significant effects of SD4 supplementation (decreased zearalenone, lower mold count, and total reduction of deoxynivalenol) within the mixed populations. Full article

Salvia miltiorrhiza Bunge (S. miltiorrhiza) is one of the most commonly used bulk herbs in China; however, root rot can seriously affect its quality and yields. To minimize the use of chemical pesticides for managing this plant fungal disease, biological control utilizing microbial bio-pesticides offers a promising alternative. This study aimed to enhance the biocontrol resources available for combating S. miltiorrhiza root rot by isolating actinomycetes with antifungal activity from the rhizosphere soil of S. miltiorrhiza and identifying biocontrol actinomycetes with a preventive effect on root rot. A total of 35 actinomycetes were successfully screened from the rhizosphere soil of S. miltiorrhizae. The strain B-35 with the strongest antifungal activity was screened out through antagonizing the pathogen Fusarium solani of S. miltiorrhiza, strain morphology and 16S rRNA analysis. The antagonistic actinomycetes fermentation filtrate and crude extract could significantly destroy the mycelium and spores of Fusarium solani; the biocontrol effect of mature S. miltiorrhiza rhizome reached 83.3%, and the number of leaves, plant height and biomass in the B-35 treatment group were significantly increased compared with the control group. B-35 has a certain application potential in the biological control of root rot and the promotion of S. miltiorrhizae. The antifungal activity of actinomycetes sourced from the rhizosphere soil of S. miltiorrhiza has been demonstrated for the first time, potentially enhancing future crop quality and production. Full article

Secondary metabolism is one of the main mechanisms Trichoderma uses to explore and colonize new niches, and 6-pentyl-α-pyrone (6-PP) is an important secondary metabolite in this process. This work focused on standardizing a method to investigate the production of 6-PP. Ethanol and ethyl acetate were both effective solvents for quantifying 6-PP in solution and had limited solubility in potato–dextrose–broth media. The 6-PP extraction using ethyl acetate provided a rapid and efficient process to recover this metabolite. The 6-PP was readily produced during the development of Trichoderma atroviride growing in the dark, but light suppressed its production. The 6-PP was purified, and its spectrum by nuclear magnetic resonance and mass spectroscopy was identical to that of commercial 6-PP. Light also induced or suppressed other unidentified metabolites in several other species of Trichoderma. The antagonistic activity of T. atroviride was influenced by light, as suppression of plant pathogens was greater in the dark. The secreted metabolite production on potato–dextrose–agar was differentially regulated by light, indicating that Trichoderma produced several metabolites with antagonistic activity against plant pathogens. Light has an important influence on the secondary metabolism and antagonistic activity of Trichoderma, and this trait is of key relevance for selecting antagonistic Trichoderma strains for plant protection. Full article

This study characterized an endophytic fungus, DJE2023, isolated from healthy banana sucker of the cultivar (cv.) Dajiao. Its potential as a biocontrol agent against banana Fusarium wilt was assessed, aiming to provide a novel candidate strain for the biological control of the devastating disease. The fungus was isolated using standard plant tissue separation techniques and fungal culture methods, followed by identification through morphological comparisons, multi-gene phylogenetic analyses, and molecular detection targeting Fusarium oxysporum f. sp. cubense (Foc) race 1 and race 4. Furthermore, assessments of its characteristics and antagonistic effects were conducted through pathogenicity tests, biological trait investigations, and dual-culture experiments. The results confirmed isolate DJE2023 to be a member of the Fusarium oxysporum species complex but distinct from Foc race 1 or race 4, exhibiting no pathogenicity to banana plantlets of cv. Fenza No.1 or tomato seedlings cv. money maker. Only minute and brown necrotic spots were observed at the rhizomes of banana plantlets of ‘Dajiao’ and ‘Baxijiao’ upon inoculation, contrasting markedly with the extensive necrosis induced by Foc tropical race 4 strain XJZ2 at those of banana cv Baxijiao. Notably, co-inoculation with DJE2023 and XJZ2 revealed a significantly reduced disease severity compared to inoculation with XJZ2 alone. An in vitro plate confrontation assay showed no significant antagonistic effects against Foc, indicating a suppressive effect rather than direct antagonism of DJE2023. Research on the biological characteristics of DJE2023 indicated lactose as the optimal carbon source for its growth, while maltose favored sporulation. The optimal growth temperature for this strain is 28 °C, and its spores can germinate effectively within the range of 25–45 °C and pH 4–10, demonstrating a strong alkali tolerance. Collectively, our findings suggest that DJE2023 exhibits weak or non-pathogenic properties and lacks direct antagonism against Foc, yet imparts a degree of resistance against banana Fusarium wilt. The detailed information provides valuable insight into the potential role of DJE2023 in integrated banana disease control, presenting a promising candidate for biocontrol against banana Fusarium wilt. Full article

Trade-offs between different defense traits exist commonly in plants. However, no evidence suggests that symbiotic microbes can drive a trade-off between plant pathogen and herbivore defense. The present study aims to investigate whether the mixture of epiphytic Fusarium oxysporum and Fusarium fujikuroi can drive the trade-off between the two defense traits in invasive Ipomoea cairica. Surface-sterilized I. cairica cuttings pre-inoculated with the epiphytic fungal mixture served as an epiphyte-inoculated (E+) group, while cuttings sprayed with sterile PDB served as an epiphyte-free (E−) group. After 3 days of incubation, E+ and E− cuttings were subjected to the challenge from a fungal pathogen and an insect herbivore, respectively. The results suggested that E+ cuttings had less rotted and yellowed leaf rates per plant than E− cuttings after Colletotrichum gloeosporioides infection. On the contrary, E+ cuttings had higher absolute and relative fresh weight losses per leaf than E− cuttings after Taiwania circumdata introduction. In the absence of challenges from the two natural enemies, salicylic acid and H₂O₂ accumulation occurred in E+ cuttings, which activated their SA-dependent pathogen defense and resulted in an increase in chitinase and β-1,3-glucanase activities. Although jasmonic acid accumulation also occurred in E+ cuttings, their JA-dependent herbivore defense responses were antagonized by SA signaling, leading to a decrease in total phenol content and phenylalanine ammonia-lyase activity. The activity of generalized defense enzymes, including superoxide dismutase, peroxidase, and catalase, did not differ between E+ and E− cuttings. Together, our findings indicate that a trade-off between pathogen and herbivore defense in I. cairica had already been driven by the epiphytic fungal mixture before the challenge by the two natural enemies. This study provides a novel insight into biocontrol strategies for I. cairica. Full article

Candida albicans is the most prevalent fungal microorganism of human microbiota and one of the few fungi capable of causing diseases in humans, depending on the host’s immune defense capacity. The similarity between fungal and host cells promotes several adverse effects during antifungal pharmacotherapy, and antimicrobial resistance increase is a major concern. Therefore, the search for alternative treatments and prevention strategies is urgent. In this context, probiotic bacteria, such as the strain Enterococcus faecium CRL 183, seem to be a viable alternative with its benefits to the immune system, activity against pathogens, and safety use well-documented through in vitro, in vivo, and clinical studies. Thus, this study aimed to evaluate if this probiotic strain prevents C. albicans ATCC 90028 biofilm colonization in vitro. To test the anti-Candida activity of the probiotic strain E. faecium CRL 183, we combined polymicrobial biofilms (C. albicans + E. faecium) with different proportions of fungi: a probiotic was formed (1:1, 1:10, 1:100) during the formation (24 h) and maturation (48 h) periods of the biofilm. The results show that E. faecium established itself with C. albicans in polymicrobial biofilms without losing its cellular viability. The probiotic strain significantly antagonized (p < 0.0001) C. albicans biofilm formation (up to 99.9% reduction in 24 h) and maturation (up to 99.43% reduction in 48 h). According to these results, E. faecium CRL183 may be a promising resource to prevent the formation of fungal biofilms. Full article

Eighty percent of grape production is destined for the wine industry, which generates various types of waste, of which grape pomace is the main one, accounting for 50–60% of waste created during processing. This waste could be a promising source of bioactive compounds (e.g., flavonoids and tannin), which are known for their antioxidant properties. Although these byproducts pose disposal challenges, they can be utilized as a substrate for solid-state fermentation bioprocess using co-cultures, where different microorganisms can interact and complement each other, improving the efficiency of metabolite production or substrate degradation. This study investigates the extraction of phenolic compounds and the antioxidant activity of the compounds from grape pomace in the solid-state fermentation bioprocess, comparing fungal and yeast monocultures, and then exploring the use of two co-cultures (P. stipites/A. niger GH1 and S. cerevisiae/A. niger) on the flavonoid extractive process. Fermentation kinetics were evaluated over 120 h, with sampling done every 12 h. Initially, yeasts were used to reduce the content of simple sugars in the medium, and fungus was added at 24 h into the process due to its ability to produce a broad spectrum of extracellular enzymes, allowing a higher efficiency in substrate degradation. Competition or antagonism during co-culture leads to significantly higher production of compounds, which are recovered using different solvents. The evaluation included phenolic compounds (total polyphenols, condensed tannins, and total flavonoids), antioxidant activity (DPPH●/FRAP), molecular characterization (HPLC-MS), and structural microscopy during the bioprocess. The highest titers obtained were 62.46 g/L for total flavonoids and 32.04 g/L for condensed tannins, using acetone as the solvent in co-culture with P. stipitis after 120 h of fermentation. Characterization identified 38 compounds, highlighting families of flavonols, hydroxybenzoic acids, and hydroxycinnamic acids. The co-culture of P. stipitis and A. niger GH1 significantly improved the extraction yield of bioactive compounds through solid-state fermentation. Full article

Fusarium pseudograminearum (Fpg) is a significant pathogen responsible for fusarium crown rot (FCR) in wheat (Triticum aestivum L.), a disease with devastating impacts on crop yield. The utilization of biocontrol bacteria to combat fungal diseases in plants is a cost-effective, eco-friendly, and sustainable strategy. In this trial, an endophytic bacterial species, designated as SW, was isolated from the roots of wheat. The strain exhibited potent antagonistic effects against Fpg and reduced the FCR disease severity index by 76.07 ± 0.33% in a greenhouse pot trial. Here, 10⁶ colony-forming units (CFUs)/mL of the SW strain was determined to be the minimum dose required to exhibit the antagonism against Fpg. The strain was identified as Bacillus atrophaeus using genome sequencing and comparison with type strains in the NCBI database. Whole-genome sequencing analysis revealed that SW harbors genes for siderophores, antifungal metabolites, and antibiotics, which are key contributors to its antagonistic activity. Additionally, the strain’s ability to utilize various carbon and nitrogen sources, successfully colonize wheat root tissues as an endophyte, and form biofilms are critical attributes for promoting plant growth. In summary, these findings demonstrate the ability of Bacillus atrophaeus to control FCR disease in wheat in a sustainable agricultural setting. Full article

Fungal phytopathogens represent a large and economically significant challenge to food production worldwide. Thus, the application of biocontrol agents can be an alternative. In the present study, we carried out biological, metabolomic, and genetic analyses of three endophytic isolates from nodules of Chamaecytisus albus, classified as Pseudomonas chlororaphis acting as antifungal agents. The efficiency of production of their diffusible and volatile antifungal compounds (VOCs) was verified in antagonistic assays with the use of soil-borne phytopathogens: B. cinerea, F. oxysporum, and S. sclerotiorum. Diffusible metabolites were identified using chromatographic and spectrometric analyses (HPTLC, GC-MS, and LC-MS/MS). The phzF, phzO, and prnC genes in the genomes of bacterial strains were confirmed by PCR. In turn, the plant growth promotion (PGP) properties (production of HCN, auxins, siderophores, and hydrolytic enzymes, phosphate solubilization) of pseudomonads were bioassayed. The data analysis showed that all tested strains have broad-range antifungal activity with varying degrees of antagonism. The most abundant bioactive compounds were phenazine derivatives: phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine, and diketopiperazine derivatives as well as ortho-dialkyl-aromatic acids, pyrrolnitrin, siderophores, and HCN. The results indicate that the tested P. chlororaphis isolates exhibit characteristics of biocontrol organisms; therefore, they have potential to be used in sustainable agriculture and as commercial postharvest fungicides to be used in fruits and vegetables. Full article

The SnTox1 effector is a virulence factor of the fungal pathogen Stagonospora nodorum (Berk.), which interacts with the host susceptibility gene Snn1 in a gene-for-gene manner and causes necrosis on the leaves of sensitive wheat genotypes. It is known that salicylic acid (SA), jasmonic acid (JA) and ethylene are the key phytohormones involved in plant immunity. To date, effectors of various pathogens have been discovered that can manipulate plant hormonal pathways and even use hormone crosstalk to promote disease development. However, the role of SnTox1 in manipulating hormonal pathways has not been studied in detail. We studied the redox status and the expression of twelve genes of hormonal pathways and two MAPK genes in six bread wheat cultivars sensitive and insensitive to SnTox1 with or without treatment by SA, JA and ethephon (ethylene-releasing agent) during infection with the SnTox1-producing isolate S. nodorum 1SP. The results showed that SnTox1 controls the antagonism between the SA and JA/ethylene signaling pathways. The SA pathway was involved in the development of susceptibility, and the JA/ethylene pathways were involved in the development of wheat plants resistance to the Sn1SP isolate in the presence of a SnTox1-Snn1 interaction. SnTox1 hijacked the SA pathway to suppress catalase activity, increase hydrogen peroxide content and induce necrosis formation; it simultaneously suppresses the JA and ethylene hormonal pathways by SA. To do this, SnTox1 reprogrammed the expression of the MAPK genes TaMRK3 and TaMRK6 and the TF genes TaWRKY13, TaEIN3 and TaWRKY53b. This study provides new data on the role of SnTox1 in manipulating hormonal pathways and on the role of SA, JA and ethylene in the pathosystem wheat S. nodorum. Full article

The yield and quality of cultivated food crops are frequently compromised by the prevalent threat from fungal pathogens that can cause widespread damage in both the pre-harvest and post-harvest stages. This paper investigates the challenges posed by fungal pathogens to the sustainability and yield of essential food crops, leading to significant economic and food security repercussions. The paper critiques the long-standing reliance on synthetic fungicides, emphasizing the environmental and health concerns arising from their widespread and occasionally inappropriate use. In response, the paper explores the potential of biological control agents, specifically endophytic fungi in advancing sustainable agricultural practices. Through their diverse symbiotic relationships with host plants, these fungi exhibit strong antagonistic capabilities against phytopathogenic fungi by producing various bioactive compounds and promoting plant growth. The review elaborates on the direct and indirect mechanisms of endophytic antagonism, such as antibiosis, mycoparasitism, induction of host resistance, and competition for resources, which collectively contribute to inhibiting pathogenic fungal growth. This paper consolidates the crucial role of endophytic fungi, i.e., Acremonium, Alternaria, Arthrinium, Aspergillus, Botryosphaeria, Chaetomium, Cladosporium, Cevidencealdinia, Epicoccum, Fusarium, Gliocladium, Muscodor, Nigrospora, Paecilomyces, Penicillium, Phomopsis, Pichia, Pochonia, Pythium, Ramichloridium, Rosellinia, Talaromyces, Trichoderma, Verticillium, Wickerhamomyces, and Xylaria, in biological control, supported by the evidence drawn from more than 200 research publications. The paper pays particular attention to Muscodor, Penicillium, and Trichoderma as prominent antagonists. It also emphasizes the need for future genetic-level research to enhance the application of endophytes in biocontrol strategies aiming to highlight the importance of endophytic fungi in facilitating the transition towards more sustainable and environmentally friendly agricultural systems. Full article