Search Results (635)

Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3–10 °C) for the fresh and seed market. One of the main causes of fresh potato waste in the retail supply chain is the processing of fungal and bacterial rots during storage. Dry rot is a fungal disease that mainly affects the potato crop during storage and is responsible for 1% of tuber losses in the UK. It is produced by Fusarium spp., such as Fusarium sambucinum and F. oxysporum, which can lead to the accumulation of mycotoxins in the potato tuber. Little is known about the impact of environmental factors on the accumulation of mycotoxins in potato tubers. Understanding the ecophysiology of these fungi is key to mitigating their occurrence under commercial storage conditions. Therefore, this work aimed to elucidate the effect of three different temperatures (5, 10, and 15 °C) and two different water activities (a_w; 0.97, 0.99) on the ecophysiology and mycotoxin accumulation of F. sambucinum and F. oxysporum in a potato-based semi-synthetic medium. The mycotoxin accumulation was then studied in vivo, in potato tubers cultivated under organic farming conditions, stored for 40 days at 8.5 °C. Results showed that higher temperatures and a_w enhanced fungal growth, lag time, and mycotoxin accumulation in vitro. Growth rate was 2 and 3.6 times higher when the temperature increased from 5 to 10 and 15 °C, respectively. Six different mycotoxins (T-2, HT-2, diacetoxyscirpenol, 15-acetoxyscirpenol, neosolaniol, and beauvericin) were detected in vitro and in vivo. T-2 was the most abundant mycotoxin detected in vitro, observing 10⁶ ng of T-2/g media after 21 days of incubation at 10 °C and 0.99 a_w. Due to the long period of time that potato tubers spend in storage, the fluctuations of environmental factors, such as temperature and relative humidity, could promote the development of fungal rot, as well as mycotoxin accumulation. This could result in important food and economic losses for the potato market and a threat to food safety. Full article

Fusarium oxysporum is a widespread soil-borne fungal pathogen that can infect various plants, causing wilt and root rot diseases. The root rot disease of Atractylodes macrocephala caused by F. oxysporum is among the most serious diseases associated with continuous cropping, significantly hindering its sustainable development. In this study, we aimed to investigate the effect of exogenous application of double-stranded RNA (dsRNA) on silencing the F. oxysporum Tup1 gene to reduce its virulence and to evaluate its potential application in controlling root rot disease in A. macrocephala. The Tup1 gene was amplified from the F. oxysporum genome, and different lengths of Tup1-dsRNA were designed and synthesized. The uptake of dsRNA by the fungus was verified using Tup1-dsRNA labeled with fluorescein, and in vitro dsRNA treatment experiments were conducted to assess its impact on the growth and virulence of F. oxysporum. Additionally, Tup1-dsRNA was applied to the roots of A. macrocephala to evaluate its effectiveness in controlling root rot disease. The experimental results showed that F. oxysporum could effectively uptake exogenously applied Tup1-dsRNA, significantly reducing Tup1 gene expression. All lengths of Tup1-dsRNA inhibited fungal growth and caused morphological changes in the fungal hyphae. Further plant experiments and Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) analysis indicated that Tup1-dsRNA treatment significantly reduced the incidence of root rot disease in A. macrocephala, which was supported by the reduction in peroxidase (POD) and catalase (CAT) enzyme activities, malondialdehyde (MDA) content, and proline (Pro) levels in treated root tissues. This study demonstrated that exogenous dsRNA could reduce the virulence of F. oxysporum by silencing the Tup1 gene and effectively mitigate the root rot disease it causes in A. macrocephala. The successful application of Tup1-dsRNA provided strong evidence for the potential of RNA interference (RNAi) technology in plant disease control. Future research could further optimize the design and application of dsRNA to enhance its practical value in agriculture. Full article

Fusarium oxysporum is one of the most economically important plant fungal pathogens, causing devastating Fusarium wilt diseases on a diverse range of hosts, including many key crop plants. Consequently, F. oxysporum has been the subject of extensive research to help develop and improve crop protection strategies. The sequencing of the F. oxysporum genome 14 years ago has greatly accelerated the discovery and characterization of key genes contributing to F. oxysporum biology and virulence. In this review, we summarize important findings on the molecular mechanisms of F. oxysporum growth, reproduction, and virulence. In particular, we focus on genes studied through mutant analysis, covering genes involved in diverse processes such as metabolism, stress tolerance, sporulation, and pathogenicity, as well as the signaling pathways that regulate them. In doing so, we hope to present a comprehensive review of the molecular understanding of F. oxysporum that will aid the future study of this and related species. Full article

The exploration of microbial genetic resources for the production of fFen-flavor Baijiu has not only enriched the microbial library for baijiu production but has also laid the foundation for process improvement and strain optimization in baijiu brewing. In this study, a total of 177 fungal isolates were screened, including Saccharomyces cerevisiae, non-Saccharomyces cerevisiae, molds, and some pathogenic bacteria. Among them, Saccharomyces cerevisiae was the most abundant with 119 isolates, playing a major role in the fermentation of baijiu production. A total of 148 bacterial isolates were obtained from the fermentation mash samples, showing greater diversity compared to fungi. Bacillus species were the most abundant, with 94 isolates. Bacillus licheniformis, in particular, can produce a rich enzymatic system and flavor precursors, making it an important contributor to the sensory quality of baijiu. Lactic acid bacteria were the second most abundant, with 16 isolates. Additionally, five pathogenic fungal species were identified, including Candida pelliculosa, Candida lusitaniae, Fusarium oxysporum, Fusarium solani and Talaromyces marneffei. Six pathogenic bacterial species were also isolated, namely Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus xylosus, Moraxella osloensis, Actinomyces meyeri and Stenotrophomonas maltophilia. Finally, two strains of high acetate ethyl ester-producing yeast and lactate-degrading bacteria with good tolerance to temperature, pH, and ethanol concentration were identified as Saccharomyces cerevisiae and Bacillus licheniformis, respectively. 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 genus Pycnoporus includes fungi with great potential for the production of antibiotic substances. It is necessary to develop new models to assess their effectiveness against microorganisms with an economic impact, such as phytopathogenic fungi. The objective of this study is to evaluate three models of Pycnoporus sanguineus for the growth inhibition of the phytopathogens Botrytis cinerea and Fusarium oxysporum. Model 1 involves dual tests of the antagonistic activity of P. sanguineus vs. phytopathogens, Model 2 involves antifungal effectiveness tests of cinnabarin, and Model 3 involves antifungal effectiveness tests of P. sanguineus extract. Models 2 and 3 are contrasted with products containing benomyl and captan. The results show that Model 3 is the most effective in controlling B. cinerea, with an inhibition percentage of 74.34% (p < 0.05) and a decrease in the growth rate (3.85 mm/day; p < 0.05); the same is true for F. oxysporum, with an inhibition percentage of 47.14% (p < 0.05). In general, F. oxysporum exhibits greater resistance (p < 0.05). The results of this study indicate that P. sanguineus extracts may be used as control agents for fungal species in the same way as other Pycnoporus species. Although commercial products are very efficient at inhibiting phytopathogens, one must consider the disadvantages of their use. In the short term, new models involving Pycnoporus for biological control in food production will be developed. Full article

Cucumber wilt, caused by Fusarium oxysporum f. sp. cucumerinum (FOC), is a soilborne disease that poses a significant threat to cucumber production, resulting in substantial yield losses. This study aimed to evaluate the biocontrol and growth-promoting effects of Bacillus velezensis, a highly active bacterial strain. In vitro assays revealed that B. velezensis F9 exhibited broad-spectrum antifungal activity against eight plant pathogenic fungi, with inhibition ratio ranging from 62.66% to 88.18%. Additionally, the strain displayed the ability to produce IAA (5.97 ± 1.75 µg/mL), fix nitrogen, produce siderophores, and form biofilms. In vitro growth promotion assays demonstrated that different concentrations of B. velezensis F9 significantly promoted cucumber seedling growth. Furthermore, two pot experiments revealed that the strain exhibited biocontrol efficacy against cucumber wilt, with disease control rates ranging from 42.86% to 67.78%. Notably, the strain significantly increased the plant height, fresh weight, and dry weight, with increases ranging from 20.67% to 60.04%, 40.27% to 75.51%, and 22.07% to 52.54%, respectively. Two field trials confirmed the efficacy of B. velezensis F9 in controlling cucumber wilt, with disease control rates of 44.95% and 33.99%, respectively. The strain effectively alleviated the dwarfing and wilting symptoms caused by the pathogen. Compared with the FOC treatment, the F9 + FOC treatment significantly increased the plant height, fresh weight, and dry weight, with increases of 43.85% and 56.28%, 49.49% and 23.70%, and 36.25% and 73.63%, respectively. Enzyme activity assays indicated that inoculation significantly increased SOD activity in cucumber leaves and neutral phosphatase, sucrase, and urease activity in rhizosphere soil. Correlation analysis revealed a negative correlation between the disease index and plant height, fresh weight, dry weight, and peroxidase activity, with correlation coefficients of −0.53, −0.60, −0.38, and −0.45, respectively. These findings suggest that plant height, fresh weight, and dry weight are significantly negatively correlated with the cucumber disease index, highlighting their importance as indicators for evaluating the biocontrol efficacy of B. velezensis F9. In conclusion, B. velezensis F9 is a highly effective plant growth-promoting rhizobacterium with excellent biocontrol potential, showcasing promising applications in agricultural production. Full article

Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici has severely threatened sustainable greenhouse tomato production. However, the effects of nutrient enrichment due to excessive fertilization on Fusarium wilt remain unclear. This study aimed to investigate the relationships among soil nutrient enrichment, microbial community structure, and the occurrence of Fusarium wilt under greenhouse conditions. This study used chemical analysis and microbiological techniques to analyze rhizosphere soil samples from greenhouse tomato production areas with varying degrees of Fusarium wilt. The results showed that, as compared with the Health group, the rhizosphere soil of Disease group has a significant nutrient enrichment, which significantly influences bacterial diversity and structure. Particularly when soil NO₃⁻–N content exceeds 170.43 mg kg⁻¹, there was a significant reduction in the relative abundance of key biocontrol bacteria such as Bacillus and Lysinibacillus. This reduction indirectly contributes to an increase in Fusarium oxysporum abundance, subsequently elevating the likelihood of pathogen infection. Furthermore, the Disease group also exhibited a simplified co-occurrence network with a 22.37% reduction in competitive interactions between bacteria and fungi. These changes might collectively increase the risk of tomato Fusarium wilt infection. Meanwhile, the relative abundance of bacteria carrying antibiotic resistance genes significantly increased in the Disease group, which also reduced soil resistance. Together, the results presented here not only uncover the effect of long-term excessive fertilization on the occurrence of Fusarium wilt but also advance our understanding of the interactions among soil nutrient management and microbial communities in the tomato rhizosphere, which provides a scientific basis for formulating strategies to prevent soil-borne diseases in greenhouse tomatoes. Full article

Flax (Linum usitatissimum L.) is an important crop plant with pharmaceutical significance. It is described in pharmacopoeias (the United States Pharmacopeia and the European Pharmacopoeia), which confirms that it (especially the seeds) is a valuable medicinal product. Similar to flax seeds, which accumulate bioactive compounds, flax in vitro cultures are also a rich source of flavonoids, phenolics, lignans and neolignans. In the present study, flax suspension cultures after treatment of the non-pathogenic Fusarium oxysporum strain Fo47 were established and analyzed. The study examined the suitability of Fo47 as an elicitor in flax suspension cultures and provided interesting data on the impact of these endophytic fungi on plant metabolism and physiology. Two flax cultivars (Bukoz and Nike) and two compositions of media for flax callus liquid cultures were tested. Biochemical analysis revealed enhanced levels of secondary metabolites (total flavonoid and total phenolic content) and photosynthetically active pigments in the flax callus cultures after treatment with the non-pathogenic fungal strain F. oxysporum Fo47 when compared to control, untreated cultures. In cultures with the selected, optimized conditions, FTIR analysis was performed and revealed changes in the structural properties of cell wall polymers after elicitation of cultures with F. oxysporum Fo47. The plant cell wall polymers were more strongly bound, and the crystallinity index (Icr) of cellulose was higher than in control, untreated samples. However, lignin and pectin levels were lower in the flax callus liquid cultures treated with the non-pathogenic strain of Fusarium when compared to the untreated control. The potential application of the non-pathogenic strain of F. oxysporum for enhancing the synthesis of desired secondary metabolites in plant tissue cultures is discussed. Full article

This study aimed to assess the effect of using selected herbs as companion crops in soybean cultivation on the yield and overall health of soybeans. A three-year field experiment (2021–2023) was conducted using a randomized block design with three replications, where the primary experimental variable was the sowing method. The innovative cropping system involved cultivating soybeans alongside different companion herbs, such as alyssum (Lobularia maritima L.), fennel (Foeniculum vulgare Mill.), borage (Borago officinalis L.), French marigold (Tagetes patula L.), calendula (Calendula officinalis L.), and a herbal mixture referred to as ‘MIX’. The study showed that cultivation of soybean with fennel improved the quantitative and qualitative characteristics of the yield, with a significant increase in seed yield (on average by 0.27 t ha⁻¹) as well as protein (7.67%) and oil yield (8.57%) compared to the pure soybean crop. The following fungal diseases were identified during the three-year study period (2021–2023): Cercospora leaf blight, Ascochyta blight, Fusarium wilt, and downy mildew. Cultivation of soybean with herbs as companion crops was implemented to improve the health of soybean to a varied extent. Borage, marigold, and calendula companion crops reduced infection of soybean by the fungi C. kikuchii and F. oxysporum. Cultivation with fennel and marigold was also beneficial for soybean health. On the other hand, cultivation with sweet alyssum and a mixture of herbs increased the occurrence of the fungus A. sojaecola. Cultivation of soybean in association with herbs is legitimate and requires further research given the priorities facing 21st-century agriculture. Full article

Fusarium crown and root rot (FCRR), caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL), is an economically important disease that affects tomatoes worldwide and has become more prevalent in China in recent years. In 2021 and 2022, tomato plants in greenhouses in Hohhot, Inner Mongolia, were observed showing symptoms of stunting, premature loss of lower leaves, and root rot. Fungal pathogens were isolated from 20 infected tomato plants and identified based on morphological observation and DNA sequencing. Twelve isolates were consistently identified as Fusarium oxysporum f. sp. radicis-lycopersici (FORL) via an analysis of the ITS, TEF-1α, and pgx4 genes. This is the first report of FORL in Inner Mongolia, China. The isolates were examined for their pathogenicity by inoculating them on tomatoes, eggplants, peppers, and chickpeas. The fungicide sensitivity of the isolates was determined. Effective concentrations for 50% growth inhibition (EC₅₀) were measured using seven fungicides. The EC₅₀ values of tebuconazole and prochloraz were <1.0 μg·mL⁻¹, exhibiting the most effective inhibition among the fungicides tested. Additionally, FORL resistance screening of tomato germplasms was performed. One tomato variety was resistant to FORL, and the remaining 43 germplasm lines showed various levels of resistance. The rates of highly susceptible, moderately susceptible, susceptible, and moderately resistant germplasms accounted for 29.55%, 22.73%, 40.91%, and 4.55% of the 44 germplasms tested, respectively. Full article

Lettuce is the most cultivated leafy vegetable in Greece; however, due to the adopted intensive cropping system, its cultivation is susceptible to many soilborne pathogens that cause significant yield and quality losses. In the current study, the impact of various soil disinfestation methods such as solarization, chemical disinfestation, and application of a biofungicide were evaluated in a commercial field that has been repeatedly used for lettuce cultivation. The populations of soilborne pathogens Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Fusarium equiseti were measured via qPCR before and after the implementation of the specific disinfestation methods. Although all the tested methods significantly reduced the population of the four soilborne pathogens, soil solarization was the most effective one. In addition, solarization reduced the number of lettuce plants affected by the pathogens R. solani and F. equiseti, and at the same time, significantly influenced the growth of lettuce plants. Amplicon sequence analysis of 16S rRNA-encoding genes used to study the soil bacterial community structure showed that Firmicutes, Proteobacteria, and Actinobacteria were the predominant bacterial phyla in soil samples. In general, solarization had positive effects on Firmicutes and negative effects on Proteobacteria and Actinobacteria; soil fumigation with dazomet increased the relative abundance of Firmicutes and Proteobacteria and reduced the corresponding values of Actinobacteria; and biofungicide had no significant effects on the three predominant bacterial phyla. The bacterial community composition and structure varied after the application of the soil disinfestation treatments since they imposed changes in the α- and β-diversity levels. The results of this study are expected to contribute towards implementing the most effective control method against the most common soilborne pathogens in intensively cultivated fields, such as those cultivated with leafy vegetables. Full article

In plants, WRKY transcription factors play a crucial role in plant growth, development, and response to abiotic and biotic stress. Cowpea (Vigna unguiculata) is an important legume crop. However, cowpea Fusarium wilt (CFW), caused by Fusarium oxysporum f. sp. tracheiphilum (Fot), poses a serious threat to its production. In this study, we systematically identified members of the cowpea WRKY (VuWRKY) gene family and analyzed their expression patterns under CFW stress. A total of 91 WRKY transcription factors were identified in the cowpea genome. Phylogenetic and synteny analyses indicated that the expansion of VuWRKY genes in cowpea is primarily due to recent duplication events. Transcriptome analysis of cowpea inoculated with Fo revealed 31 differentially expressed VuWRKY genes, underscoring their role in the response to CFW infection. Four differentially expressed WRKY genes were selected for validation. Subcellular localization and Western blot assays showed their nuclear localization and normal expression in N. benthamiana. Additionally, yeast one-hybrid assays demonstrated that VuWRKY2 can bind to the promoter region of the Catalase (CAT) gene, indicating its potential role in transcriptional regulation. This study establishes a foundation for further exploration of the role and regulatory mechanisms of VuWRKY genes in response to CFW stress. Full article

This study investigated the effect of black soldier fly larvae (BSFL) frass derived from BSFL reared on a diet composed of fruit/vegetable/bakery/brewery residues (FVBB diet) and on the Gainesville diet (GV diet) on the development of tomato (Solanum lycopersicum) Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Tomato plants were grown in a substrate inoculated with FOL that was amended (10%, v:v) or not (control) with either a commercial compost, pasteurized (70 °C for 1 h) frass from BSFL reared on a FVBB diet, non-pasteurized frass from BSFL reared on a FVBB diet, pasteurized frass from BSFL reared on the GV diet, or non-pasteurized frass from BSFL reared on the GV diet. The results show that frass from BSFL reared on the GV diet, irrespective of pasteurization, inhibited FOL root colonization and reduced the severity of tomato Fusarium wilt to a far greater extent than frass from BSFL reared on a FVBB diet and commercial compost made of peat, seaweed, and shrimps. This study suggests that BSFL frass, depending on the larval rearing diet, has the potential to serve as a pasteurized or non-pasteurized soil amendment with prophylactic properties against FOL in tomato plants, opening new avenues of research for the valorization of BSFL frass. Full article

Cucumber is one of the top ten vegetables globally and is widely cultivated worldwide. However, Fusarium wilt, caused by Fusarium oxysporum f. sp. Cucumerinum, is one of the most serious soil-borne diseases in cucumber cultivation, causing significant economic losses. Biological control has great potential in the prevention of cucumber wilt disease, but the mechanism involved still needs further research. In this study, biocontrol isolate Bacillus subtilis 1JN2, which was isolated in our previous work, was evaluated in field conditions against Fusarium wilt, and the rhizosphere fungal diversity was analyzed. The results indicated that the biocontrol efficacy of B. subtilis 1JN2 reached 58.5% compared with the blank control, and the population density of F. oxysporum in the rhizosphere decreased from 495 copies/g of soil before inoculation to 20 copies/g 14 days after treatment. High-throughput sequencing demonstrated that after an inoculation of 1JN2, the populations that decreased significantly include the genera of Olpidium and Pseudallescheria, from more than 20% to less than 8%. And the most increased population belonged to the family Chaetomiaceae, from 6.82% to 18.77%, 12.39%, 44.41%, and 19.41% at the four sample time points after treatment. In addition, soil-related enzyme activities, including catalase, soil dehydrogenase, alkaline phosphatase, and polyphenol oxidase, were analyzed before and after treatment with 1JN2. The results indicated that all the enzyme activities showed an upward trend following inoculation. These findings demonstrate the potential of using B. subtilis 1JN2 as a biocontrol agent for controlling Fusarium wilt in cucumber. Full article