Antifungal efficacy of chitosan extracted from shrimp shell on strawberry (Fragaria × ananassa) postharvest spoilage fungi

The strong demand for biological materials in the food industry places chitosan at the forefront of other biopolymers. The present study aims to evaluate the antifungal properties of chitosan extracted from shrimp shell waste (Parapenaeus longirostris) against post-harvest strawberry (Fragaria × ananassa) spoilage fungi. The physicochemical characteristics (DD, Mw, and solubility) of extracted chitosan were determined. In addition, functional characteristics were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antifungal effect of chitosan on mycelial growth and spore germination of Aspergillus niger, Botrytis cinerea, Fusarium oxysporum, and Rhizopus stolonifer was evaluated. Yield, degree of deacetylation, molecular weight, and solubility were 21.86%, 83.50%, 180 kDa, and 80.10%, respectively. A degree of deacetylation of 81.27% was calculated from the FTIR spectrum and a crystallinity index of 79.83% was determined from the X-ray diffraction pattern. SEM images of extracted chitosan showed a combination of fibrous and porous structure. At 3% chitosan, mycelial growth inhibition rates of A. niger, B. cinerea, F. oxysporum, and R. stolonifer ranged from 81.37% to 92.70%. At the same chitosan concentration, the percentages of spore germination inhibition of the isolated fungi ranged from 65.47% to 71.48%. The antifungal activity was highly dose-dependent. As a natural polymer, chitosan offers a convincing alternative to synthetic antimicrobials for the post-harvest preservation of strawberries. Its potential lies in its ability to inhibit the growth of spoilage fungi.

Lipopeptide C17 Fengycin B Exhibits a Novel Antifungal Mechanism by Triggering Metacaspase-Dependent Apoptosis in Fusarium oxysporum

Fusarium wilt is a worldwide soil-borne fungal disease caused by Fusarium oxysporum that causes serious damage to agricultural products. Therefore, preventing and treating fusarium wilt is of great significance. In this study, we purified ten single lipopeptide fengycin components from Bacillus subtilis FAJT-4 and found that C17 fengycin B inhibited the growth of F. oxysporum FJAT-31362. We observed early apoptosis hallmarks, including reactive oxygen species accumulation, mitochondrial dysfunction, and phosphatidylserine externalization in C17 fengycin B-treated F. oxysporum cells. Further data showed that C17 fengycin B induces cell apoptosis in a metacaspase-dependent manner. Importantly, we found that the expression of autophagy-related genes in the TOR signaling pathway was significantly upregulated; simultaneously, the accumulation of acidic autophagy vacuoles in F. oxysporum cell indicated that the autophagy pathway was activated during apoptosis induced by C17 fengycin B. Therefore, this study provides new insights into the antifungal mechanism of fengycin.

Segmental duplications drive the evolution of accessory regions in a major crop pathogen

Many pathogens evolved compartmentalized genomes with conserved core and variable accessory regions (ARs) that carry effector genes mediating virulence. The fungal plant pathogen Fusarium oxysporum has such ARs, often spanning entire chromosomes. The presence of specific ARs influences the host range, and horizontal transfer of ARs can modify the pathogenicity of the receiving strain. However, how these ARs evolve in strains that infect the same host remains largely unknown. We defined the pan-genome of 69 diverse F. oxysporum strains that cause Fusarium wilt of banana, a significant constraint to global banana production, and analyzed the diversity and evolution of the ARs. Accessory regions in F. oxysporum strains infecting the same banana cultivar are highly diverse, and we could not identify any shared genomic regions and in planta-induced effectors. We demonstrate that segmental duplications drive the evolution of ARs. Furthermore, we show that recent segmental duplications specifically in accessory chromosomes cause the expansion of ARs in F. oxysporum. Taken together, we conclude that extensive recent duplications drive the evolution of ARs in F. oxysporum, which contribute to the evolution of virulence.

Chemical Composition and Biocontrol Activity of Different Essential Oils against Soil-Borne Fungal Pathogens

In this study, the efficacy of the essential oil of Mentha longifolia, Achillea arabica and Artemisia absinthium plants were evaluated against important soil-borne fungal pathogens as Verticillium dahliae, Rhizoctonia solani, and Fusarium oxysporum. Essential oils were obtained from plants by hydrodistillation method and the chemical components of essential oils were determined by analyzing by gas chromatography-mass spectrometry. The main components found as piperitone oxide (13.61%), piperitenone oxide (15.55%), pulegone (12.47%), 1-menthone (5.75%), and camphor (5.75%) in M. longifolia, á-selinene 13.38%, camphor 13.34%, L-4-terpineneol 8.40%, (-)-á-Elemene 7.01%, 1,8-cineole 4.71%, and (-)-spathulenol 3.84% in A. arabica, and á-thujone (34.64%), 1,8-cineole (19.54%), pulegone (7.86%), camphene (5.31%), sabinene (4.86%), and germacrene-d (3.67%) in A. absinthium. The antifungal activities of the oils were investigated 0.05, 0.1, 0.25, 0.5, 1.00, and 2.00 μl/ml concentrations with the contact effect method. M. longifolia oil (1.00 and 2.00 μl/ml) has displayed remarkable antifungal effect and provided 100% inhibition on mycelial growth of V. dahliae, R. solani and F. oxysporum. The results obtained from this study may contribute to the development of new alternative and safe methods against soil-borne fungal pathogens.

Epidemiology and management of Fusarium wilt of Eucalyptus camaldulensis through systemic acquired resistance

Eucalyptus camaldulensis is a multifunctional tree and is globally used for the reclamation of problematic lands. Eucalyptus camaldulensis is prone to attack by a number of pathogens, but the most important threat is the Fusarium wilt (Fusarium oxysporum). Keeping in view the importance of E. camaldulensis and to manage this disease, five plant activators, i.e., salicylic acid (C7H6O3), benzoic acid (C7H6O2), citric acid (C6H8O7), dipotassium phosphate (K2HPO4), monopotassium phosphate (KH2PO4) and nutritional mixture namely Compound (NPK) and nutriotop (Fe, Zn, Cu, B, Mn) were evaluated in the Fusarium infested field under RCBD in the Research Area, Department of Forestry and Range Management, University of Agriculture, Faisalabad (UAF). Among plant activators, salicylic acid and a combination of compound + nutriotop exhibited the lowest disease incidence and enhanced fresh and dry weight of leaves compared to other treatments and control. Results of the environmental study indicated maximum disease incidence between 35-40 °C (max. T), 6-25 °C (mini. T), 70-80% relative humidity and 1.5-2.5 km/h wind speed while pan evaporation expressed weak correlation with disease development. It was concluded that Fusarium wilt of Eucalyptus camaldulensis could be managed through activation of the basal defense system of the host plant with provision of salicylic acid and balanced nutrition by considering environmental factors. Recent exploration is expected to be helpful for future research efforts on epidemiology and ecologically sound intervention of Fusarium wilt of Eucalyptus camaldulensis.

Endophytic non-pathogenic Fusarium oxysporum reorganizes the cell wall in flax seedlings

Introduction

Flax (Linum usitatissimum) is a crop producing valuable products like seeds and fiber. However, its cultivation faces challenges from environmental stress factors and significant yield losses due to fungal infections. The major threat is Fusarium oxysporum f.sp lini, causing fusarium wilt of flax. Interestingly, within the Fusarium family, there are non-pathogenic strains known as biocontrols, which protect plants from infections caused by pathogenic strains. When exposed to a non-pathogenic strain, flax exhibits defense responses similar to those seen during pathogenic infections. This sensitization process activates immune reactions, preparing the plant to better combat potential pathogenic strains. The plant cell wall is crucial for defending against pathogens. It serves as the primary barrier, blocking pathogen entry into plant cells.

Methods

The aim of the study was to investigate the effects of treating flax with a non-pathogenic Fusarium oxysporum strain, focusing on cell wall remodeling. The infection's progress was monitored by determining the fungal DNA content and microscopic observation. The plant defense response was confirmed by an increase in the level of Pathogenesis-Related (PR) genes transcripts. The reorganization of flax cell wall during non-pathogenic Fusarium oxysporum strain infection was examined using Infrared spectroscopy (IR), determination of cell wall polymer content, and analysis of mRNA level of genes involved in their metabolism.

Results and discussion

IR analysis revealed reduced cellulose content in flax seedlings after treatment with Fo47 and that the cellulose chains were shorter and more loosely bound. Hemicellulose content was also reduced but only after 12h and 36h. The total pectin content remained unchanged, while the relative share of simple sugars and uronic acids in the pectin fractions changed over time. In addition, a dynamic change in the level of methylesterification of carboxyl groups of pectin was observed in flax seedlings treated with Fo47 compared to untreated seedlings. The increase in lignin content was observed only 48 hours after the treatment with non-pathogenic Fusarium oxysporum. Analysis of mRNA levels of cell wall polymer metabolism genes showed significant changes over time in all analyzed genes. In conclusion, the research suggests that the rearrangement of the cell wall is likely one of the mechanisms behind flax sensitization by the non-pathogenic Fusarium oxysporum strain. Understanding these processes could help in developing strategies to enhance flax's resistance to fusarium wilt and improve its overall yield and quality.

Protective effects of hepatic diseases by bioactive phytochemicals in Fusarium oxysporum - A review

Lately, liver diseases were categorized as one of the most prevalent health problems globally as it causes a severe threat to mankind all over the world due to the wide range of occurrence. There are multiple factors causing hepatic disorders, such as alcohol, virus, poisons, adverse effects of drugs, poor diet, inherited conditions and obesity. Liver diseases have various types including alcoholic liver disease, non-alcoholic fatty liver disease, autoimmune hepatitis, liver cancer, hepatocellular carcinoma, liver fibrosis and hepatic inflammation. Therefore, it is imperative to find effective and efficacious agents in managing liver diseases. Fusarium oxysporum, an endophytic fungus and containing many bioactive compounds, could be served as a forked medication for enormous number and types of maladies. It was characterized by producing biochemical compounds which had rare pharmacological properties as it may be found in a limit number of other medicinal plants. The majority of the past researches related to Fusarium oxysporum recited the fungal negative field either on the pathogenic effects of the fungus on economical crops or on the fungal chemical components to know how to resist it. The present review will highlight on the bright side of Fusarium oxysporum and introduce the functional activities of its chemical compounds for treating its target diseases. The key point of illustrated studies in this article is displaying wide range of detected bioactive compounds isolated from Fusarium oxysporum and in other illustrated studies it was elucidated the therapeutical and pharmacological potency of these biologically active compounds (isolated from medicinal plants sources) against different types of liver diseases including non-alcoholic fatty liver disease, alcoholic liver disease, cirrhosis and others. It was demonstrated that F. oxysporum contains unique types of isoflavones, flavonoids, phenols and another active chemical compounds, and these compounds showed recently a fabulous clinical contribution in the therapy of liver injury diseases, which opens new and unprecedented way for evaluating the maintaining efficacy of Fusarium oxysporum bioactive compounds in dealing with hepatic complications and its remedy impacting on liver diseases and injured hepatocytes through recommending implement a practical study.

Inhibitory effects and mechanisms of cinnamaldehyde against Fusarium oxysporum, a serious pathogen in potatoes

BACKGROUND

Potatoes, a major economic crop, are significantly impacted by Fusarium dry rot, a prevalent postharvest disease. Despite the broad-spectrum antimicrobial properties of cinnamaldehyde, a naturally-derived plant substance, its efficacy against the causal pathogen of potato dry rot (Fusarium oxysporum) and the underlying mechanisms have not been extensively studied.

RESULTS

Our study demonstrates that cinnamaldehyde effectively inhibits the growth of Fusarium oxysporum, the pathogen responsible for potato dry rot, and increases its sensitivity to environmental stress factors such as extreme temperatures and high salt stress. Treatment with cinnamaldehyde results in altered fungal mycelium morphology, compromised cell wall stability, and disrupted cell membrane integrity, thereby reducing spore viability. Specifically, it interferes with the cell membrane and cell wall structures of the fungus, potentially disrupting fungal growth by modulating signaling pathways involved in cell wall maintenance, chitin metabolism, and GPI-anchored protein function. Notably, we show that cinnamaldehyde induces a form of regulated cell death in F. oxysporum, which is characterized not as typical apoptosis, as evidenced by Annexin V negative staining. However, the specific cell death type and underlying mechanism still needed to be further explored.

CONCLUSION

Cinnamaldehyde, an environmentally friendly plant-based active compound, exhibits strong inhibitory effects on F. oxysporum, indicating its potential use in the prevention and control strategies for potato dry rot. This research contributes to the understanding of novel antifungal mechanisms and offers promising insights into eco-friendly alternatives for managing this economically significant postharvest disease. © 2024 Society of Chemical Industry.

Cloning and heterologous expression of Fusarium oxysporum nitrilase gene in Escherichia coli and evaluation in cyanide degradation

Cyanide is widely utilized in the extraction of precious metal extraction even though it has been deemed as the most toxic compound. Fusarium oxysporum has been shown to degrade cyanide through the activity of the Nitrilase enzyme. In this study, the coding sequence of nitrilase gene from F. oxysporum genomic DNA was optimized for cloning and expression in E. coli. The pUC57 containing synthetic optimized nitrilase gene was transferred into E. coli DH5α strain. This nitrilase gene was sub-cloned into pET26b (+) expression vector containing an in-built His-tag at the C-terminal end to facilitate its purification. The recombinant plasmid, pETAM1, was confirmed by PCR, digestion pattern, and sequencing. The recombinant protein was overproduced in E. coli BL21 (DE3). The results of the SDS-PAGE pattern and Western blot analysis confirmed the expression of the expected recombinant protein. For expression optimization of Nitrilase protein, M16 orthogonal experimental design of the Taguchi method was used. The effect of induction time, temperature and IPTG concentration were examined using four levels for each factors. Estimation of the amount of the expressed protein was calculated via densitometry on SDS-PAGE. The enzyme activity and expression in E. coli proved to be successful since there was ammonia production when potassium cyanide and acrylonitrile were used as substrates while the highest enzyme activity of 88% was expressed at 30 °C. The Km and Vm values of the expressed Nitrilase enzyme were determined to be 0.68 mM and 0.48 mM/min respectively.

Chemical Constituents of a Marine-derived Fungus Fusarium oxysporum F0888 and their Antibacterial Activity

Five new compounds, including four hydroxyphenylacetic acid derivatives, stachylines H-K (1-4), a derivative of hydroxyphenylethanol (5), as well as seven known compounds were obtained from a marine-derived fungus Fusarium oxysporum F0888 isolated from sediments in the South China Sea. The structures and absolute configurations of new compounds were determined by spectroscopic (IR, NMR, and HR-ESI-MS) analyses, comparison of optical rotations, and the modified Mosher's MTPA ester method. Antimicrobial and anti-inflammatory activities of compounds 1-12 were tested. Unfortunately, all of isolated compounds were inactivity.

Endophytic fungi of Tradescantia pallida mediated targeting of Multi-Drug resistant human pathogens

Antimicrobial resistance (AMR) has emerged as one of the most serious worldwide public health issues of the twenty-first century. The expeditious rise of AMR has urged the development of new, natural effective therapeutic strategies against drug-resistant pathogens. Endophytic fungi, which inhabit distinctive environments like endosymbiotic relationships with plants, are gaining interest as alternative reservoirs for novel compounds that exhibit a broad range of chemical diversity and unique modes of action by releasing a variety of secondary metabolites with antimicrobial properties. The objective of the current research was to isolate and identify endophytic fungal species from leaves of Tradescantia pallida and to investigate their antagonistic effects on Multi-Drug-Resistant human pathogens. Endophytic fungus TPL11 and TPL14 showed maximum inhibition in agar plug and agar well diffusion assay. The ethyl acetate crude extract effectively suppressed growth of MRSA (Methicillin-resistant Staphylococcus aureus) ATCC 43300,700699 strains and VRE (Vancomycin-resistant Enterococcus) with the Inhibition zone of 22 ± 0.05, 23 ± 0.11 and 24 ± 0.11 mm respectively with minimum inhibitory concentration (MIC) of 3.125 µg/mL. Whereas TPL11 fungus revealed antibiosis of 22 ± 0.05 and 21 ± 0.15 mm against MRSA(ATCC 43300,700699) and 24 ± 0.05 mm for VRE with MIC of 6.25,3.125 and 1.56 μg/mL respectively. The MIC (Minimum inhibitory concentration) index further confirmed that both the extracts were bacteriostatic against MRSA and bactericidal against VRE. The isolates TPL11 and TPL14 were identified as Fusarium oxysporum and Nigrospora sphaerica by 18S rRNA internal transcribed spacer (ITS) sequencing. To our insight, it is the first report to reveal the presence of F.oxysporum and N.sphaerica in T.pallida and their antibacterial activity.

lycopersici effectors revealed by experimental and computational studies

Plant pathogens secrete proteins, known as effectors, that function in the apoplast or inside plant cells to promote virulence. Effector recognition by cell-surface or cytosolic receptors results in the activation of defence pathways and plant immunity. Despite their importance, our general understanding of fungal effector function and recognition by immunity receptors remains poor. One complication often associated with effectors is their high sequence diversity and lack of identifiable sequence motifs precluding prediction of structure or function. In recent years, several studies have demonstrated that fungal effectors can be grouped into structural classes, despite significant sequence variation and existence across taxonomic groups. Using protein X-ray crystallography, we identify a new structural class of effectors hidden within the secreted in xylem (SIX) effectors from Fusarium oxysporum f. sp. lycopersici (Fol). The recognised effectors Avr1 (SIX4) and Avr3 (SIX1) represent the founding members of the Fol dual-domain (FOLD) effector class, with members containing two distinct domains. Using AlphaFold2, we predicted the full SIX effector repertoire of Fol and show that SIX6 and SIX13 are also FOLD effectors, which we validated experimentally for SIX6. Based on structural prediction and comparisons, we show that FOLD effectors are present within three divisions of fungi and are expanded in pathogens and symbionts. Further structural comparisons demonstrate that Fol secretes effectors that adopt a limited number of structural folds during infection of tomato. This analysis also revealed a structural relationship between transcriptionally co-regulated effector pairs. We make use of the Avr1 structure to understand its recognition by the I receptor, which leads to disease resistance in tomato. This study represents an important advance in our understanding of Fol-tomato, and by extension plant-fungal interactions, which will assist in the development of novel control and engineering strategies to combat plant pathogens.

Green Waste Compost Impacts Microbial Functions Related to Carbohydrate Use and Active Dispersal in Plant Pathogen-Infested Soil

The effects of compost on physical and chemical characteristics of soil are well-studied but impacts on soil microbiomes are poorly understood. This research tested effects of green waste compost on bacterial communities in soil infested with the plant pathogen Fusarium oxysporum. Compost was added to pathogen-infested soil and maintained in mesocosms in a greenhouse experiment and replicated growth chamber experiments. Bacteria and F. oxysporum abundance were quantified using quantitative PCR. Taxonomic and functional characteristics of bacterial communities were measured using shotgun metagenome sequencing. Compost significantly increased bacterial abundance 8 weeks after amendment in one experiment. Compost increased concentrations of chemical characteristics of soil, including phosphorus, potassium, organic matter, and pH. In all experiments, compost significantly reduced abundance of F. oxysporum and altered the taxonomic composition of soil bacterial communities. Sixteen bacterial genera were significantly increased from compost in every experiment, potentially playing a role in pathogen suppression. In all experiments, there was a consistent negative effect of compost on functions related to carbohydrate use and a positive effect on bacteria with flagella. Results from this work demonstrate that compost can reduce the abundance of soilborne plant pathogens and raise questions about the role of microbes in plant pathogen suppression.

Complete genome sequence of Bacillus velezensis B31, a potential biocontrol agent with ability of tolerance to fusaric acid and antagonism against Fusarium oxysporum

Bacillus velezensis B31 is tolerant to fusaric acid, exhibits antagonism against Fusarium oxysporum, and has an excellent control effect on tomato fusarium wilt. Here, we present the complete genome sequence of B31, which contains 4,056,755 bp DNA with a G + C ratio of 46.39%. The genome has 3,838 protein-coding genes.

In vivo application of potent probiotics for enhancing potato growth and controlling Ralstonia solanacearum and Fusarium oxysporum infections

Plant probiotics are live microbial cells or cultures that support plant growth and control plant pathogens through different mechanisms. They have various effects on plants, including plant growth promotion through the production of indole acetic acid (IAA), biological control activity (BCA), and production of cellulase enzymes, thus inducing systemic resistance and increasing the availability of mineral elements. The present work aimed to study the potential of Achromobacter marplatensis and Bacillus velezensis as plant probiotics for the field cultivation of potatoes. In vitro studies have demonstrated the ability of selected probiotics to produce IAA and cellulase, as well as antimicrobial activity against two plant pathogens that infect Solanum tuberosum as Fusarium oxysporum and Ralstonia solanacearum under different conditions at a broad range of different temperatures and pH values. In vivo study of the effects of the probiotics A. marplatensis and B. velezensis on S. tuberosum plants grown in sandy clay loamy soil was detected after cultivation for 90 days. Probiotic isolates A. marplatensis and B. velezensis were able to tolerate ultraviolet radiation (UV) exposure for up to two hours, the dose response curve exhibited that the D10 values of A. marplatensis and B. velezensis were 28 and 16 respectively. In the case of loading both probiotics with broth, the shoot dry weight was increased significantly from 28 in the control to 50 g, shoot length increased from 24 to 45.7 cm, branches numbers increased from 40 to 70 branch, leaves number increased from 99 to 130 leaf, root dry weight increased from 9.3 to 12.9 g, root length increased from 24 to 35.7 cm, tuber weight increased from 15 to 37.0 g and tubers number increased from 9 to 24.4 tuber, the rot percentage was reduced to 0%. The addition of both probiotic isolates, either broth or wheat grains load separately has enhanced all the growth parameters; however, better results and increased production were in favor of adding probiotics with broth more than wheat. On the other hand, both probiotics showed a remarkable protective effect against potato pathogens separately and reduced the negative impact of the infection using them together.

Analysis of Marchantia polymorpha-microorganism interactions: basis for understanding plant-microbe and plant-pathogen interactions

Marchantia polymorpha is a bryophyte gaining significance as a model plant in evolutionary studies in recent years. This is attributed to its small-sequenced genome, standardized transformation methodology, global distribution, and easy and rapid in vitro culturing. As an evolutionary model, M. polymorpha contributes to our understanding of the evolution of plant defensive responses and the associated hormonal signaling pathways. Through its interaction with microorganisms, M. polymorpha serves as a valuable source of knowledge, yielding insights into new microbial species and bioactive compounds. Bibliographic analysis involved collecting, reading, and categorizing documents obtained from the Scopus and Web of Science databases using different search terms. The review was based on 30 articles published between 1995 and 2023, with Japanese and Spanish authors emerging as the most prolific contributors in this field. These articles have been grouped into four main themes: antimicrobial metabolites produced by M. polymorpha; identification and characterization of epiphytic, endophytic, and pathogenic microorganisms; molecular studies of the direct interaction between M. polymorpha and microorganisms; and plant transformation using bacterial vectors. This review highlights the key findings from these articles and identifies potential future research directions.

An endophytic fungus interacts with the defensin-like protein OsCAL1 to regulate cadmium allocation in rice

Defensin-like proteins are conserved in multicellular organisms and contribute to innate immune responses against fungal pathogens. In rice, defensins play a novel role in regulating cadmium (Cd) efflux from the cytosol. However, whether the antifungal activity of defensins correlates with Cd-efflux function remains unknown. In this study, we isolated an endophytic Fusarium, designed Fo10, by a comparative microbiome analysis of rice plants grown in a paddy contaminated with Cd. Fo10 is tolerant to high levels of Cd, but is sensitive to the defensin-like protein OsCAL1, which mediates Cd efflux to the apoplast. We found that Fo10 symbiosis in rice is regulated by OsCAL1 dynamics, and Fo10 coordinates multiple plant processes, including Cd uptake, vacuolar sequestration, efflux to the environment, and formation of Fe plaques in the rhizosphere. These processes are dependent on the salicylic acid signaling pathway to keep Cd levels low in the cytosol of rice cells and to decrease Cd levels in rice grains without any yield penalty. Fo10 also plays a role in Cd tolerance in the poaceous crop maize and wheat, but has no observed effects in the eudicot plants Arabidopsis and tomato. Taken together, these findings provide insights into the mechanistic basis underlying how a fungal endophyte and host plant interact to control Cd accumulation in host plants by adapting defense responses to promote the establishment of a symbiosis that permits adaptation to high-Cd environments.

Sir2-mediated cytoplasmic deacetylation facilitates pathogenic fungi infection in host plants

Lysine acetylation is an evolutionarily conserved and widespread post-translational modification implicated in the regulation of multiple metabolic processes, but its function remains largely unknown in plant pathogenic fungi. A comprehensive analysis combined with proteomic, molecular and cellular approaches was presented to explore the roles of cytoplasmic acetylation in Fusarium oxsysporum f.sp. lycopersici (Fol). The divergent cytoplasmic deacetylase FolSir2 was biochemically characterized, which is contributing to fungal virulence. Based on this, a total of 1752 acetylated sites in 897 proteins were identified in Fol via LC-MS/MS analysis. Further analyses of the quantitative acetylome revealed that 115 proteins representing two major pathways, translational and ribosome biogenesis, were hyperacetylated in the ∆Folsir2 strain. We experimentally examined the regulatory roles of FolSir2 on K271 deacetylation of FolGsk3, a serine/tyrosine kinase implicated in a variety of cellular functions, which was found to be crucial for the activation of FolGsk3 and thus modulated Fol pathogenicity. Cytoplasmic deacetylation by FolSir2 homologues has a similar function in Botrytis cinerea and likely other fungal pathogens. These findings reveal a conserved mechanism of silent information regulator 2-mediated cytoplasmic deacetylation that is involved in plant-fungal pathogenicity, providing a candidate target for designing broad-spectrum fungicides to control plant diseases.

Fusarium wilt constrains mungbean yield due to reduction in source availability

Mungbean is an important source of plant protein for consumers and a high-value export crop for growers across Asia, Australia and Africa. However, many commercial cultivars are highly vulnerable to biotic stresses, which rapidly reduce yield within the season. Fusarium oxysporum is a soil-borne pathogen that is a growing concern for mungbean growers globally. This pathogen causes Fusarium wilt by infecting the root system of the plant resulting in devastating yield reductions. To understand the impact of Fusarium on mungbean development and productivity and to identify tolerant genotypes, a panel of 23 diverse accessions was studied. Field trials conducted in 2016 and 2021 in Warwick, Queensland, Australia under rainfed conditions investigated the variation in phenology, canopy and yield component traits under disease and disease-free conditions. Analyses revealed a high degree of genetic variation for all traits. By comparing the performance of these traits across these two environments, we identified key traits that underpin yield under disease and disease-free conditions. Aboveground biomass components at 50 % flowering were identified as significant drivers of yield development under disease-free conditions and when impacted by Fusarium resulted in up to 96 % yield reduction. Additionally, eight genotypes were identified to be tolerant to Fusarium. These genotypes were found to display differing phenological and morphological behaviours, thereby demonstrating the potential to breed tolerant lines with a range of diverse trait variations. The identification of tolerant genotypes that sustain yield under disease pressure may be exploited in crop improvement programs.

pisi Associated with Root Rot of Field Pea in North Dakota and the Effects of Temperature on Aggressiveness

Fusarium root rot is an important disease of field pea (Pisum sativum var. sativum L.) that occurs everywhere pea is grown, causing yield loss of up to 75%. Fusarium root rot is caused by a complex of Fusarium species, most notably Fusarium solani in the Pacific Northwest of the United States and F. avenaceum in the northern Great Plains of the United States and Canada. F. oxysporum f. sp. pisi (Fop) was frequently isolated from peas exhibiting root rot symptoms in North Dakota during recent surveys. Fop causes wilt (races 1, 5, and 6) and near wilt (race 2) on pea. However, its contribution to pea root rot remains unclear. Fop race was determined for isolates from North Dakota pea root rot surveys. ND Fop isolates were evaluated for root rot pathogenicity and aggressiveness at standard and elevated temperatures. Results from greenhouse wilt assays indicated that all Fop races exist in North Dakota, with race 2 most prevalent among the 25 North Dakota isolates evaluated. Root rot evaluations conducted at 21/18°C and 25/19°C day/night temperatures demonstrated that most Fop isolates were as aggressive or more aggressive than F. solani and F. avenaceum under both temperature regimes. Aggressiveness of Fop isolates tended to increase at elevated assay temperatures. Results from these experiments indicate that Fop may be an important contributor to the root rot complex of field pea in North Dakota and should be considered in integrated pest management strategies, including pea breeding efforts to improve resistance to Fusarium root rot.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The melon Fom-1-Prv resistance gene pair: Correlated spatial expression and interaction with a viral protein

The head-to-head oriented pair of melon resistance genes, Fom-1 and Prv, control resistance to Fusarium oxysporum races 0 and 2 and papaya ringspot virus (PRSV), respectively. They encode, via several RNA splice variants, TIR-NBS-LRR proteins, and Prv has a C-terminal extra domain with a second NBS homologous sequence. In other systems, paired R-proteins were shown to operate by "labor division," with one protein having an extra integrated domain that directly binds the pathogen's Avr factor, and the second protein executing the defense response. We report that the expression of the two genes in two pairs of near-isogenic lines was higher in the resistant isoline and inducible by F. oxysporum race 2 but not by PRSV. The intergenic DNA region separating the coding sequences of the two genes acted as a bi-directional promoter and drove GUS expression in transgenic melon roots and transgenic tobacco plants. Expression of both genes was strong in melon root tips, around the root vascular cylinder, and the phloem and xylem parenchyma of tobacco stems and petioles. The pattern of GUS expression suggests coordinated expression of the two genes. In agreement with the above model, Prv's extra domain was shown to interact with the cylindrical inclusion protein of PRSV both in yeast cells and in planta.

unraveled by dual transcriptomics

KEY MESSAGE

Phenylpropanoid biosynthesis and plant-pathogen interaction pathways in saffron and cell wall degrading enzymes in Fusarium oxysporum R1 are key players involved in the interaction. Fusarium oxysporum causes corm rot in saffron (Crocus sativus L.), which is one of the most devastating fungal diseases impacting saffron yield globally. Though the corm rot agent and its symptoms are known widely, little is known about the defense mechanism of saffron in response to Fusarium oxysporum infection at molecular level. Therefore, the current study reports saffron-Fusarium oxysporum R1 (Fox R1) interaction at the molecular level using dual a transcriptomics approach. The results indicated the activation of various defense related pathways such as the mitogen activated protein kinase pathway (MAPK), plant-hormone signaling pathways, plant-pathogen interaction pathway, phenylpropanoid biosynthesis pathway and PR protein synthesis in the host during the interaction. The activation of pathways is involved in the hypersensitive response, production of various secondary metabolites, strengthening of the host cell wall, systemic acquired resistance etc. Concurrently, in the pathogen, 60 genes reported to be linked to pathogenicity and virulence has been identified during the invasion. The expression of genes encoding plant cell wall degrading enzymes, various transcription factors and effector proteins indicated the strong pathogenicity of Fusarium oxysporum R1. Based on the results obtained, the putative molecular mechanism of the saffron-Fox R1 interaction was identified. As saffron is a male sterile plant, and can only be improved by genetic manipulation, this work will serve as a foundation for identifying genes that can be used to create saffron varieties, resistant to Fusarium oxysporum infection.

Combatting Sugar Beet Root Rot: Streptomyces Strains' Efficacy against Fusarium oxysporum

Sugar beet root rot disease triggered by Fusarium oxysporum f. sp. radicis-betae is a destructive disease and dramatically affects the production and quality of the sugar beet industry. Employing beneficial microorganisms as a biocontrol strategy represents an eco-friendly and sustainable approach to combat various plant diseases. The distinct aspect of this study was to assess the antifungal and plant growth-promoting capabilities of recently isolated Streptomyces to treat sugar beet plants against infection with the phytopathogen F. oxysporum. Thirty-seven actinobacterial isolates were recovered from the rhizosphere of healthy sugar beet plants and screened for their potential to antagonize F. oxysporum in vitro. Two isolates SB3-15 and SB2-23 that displayed higher antagonistic effects were morphologically and molecularly identified as Streptomyces spp. Seed treatment with the fermentation broth of the selected Streptomyces strains SB3-15 and SB2-23 significantly reduced disease severity compared to the infected control in a greenhouse experiment. Streptomyces SB2-23 exhibited the highest protective activity with high efficacy ranging from 91.06 to 94.77% compared to chemical fungicide (86.44 to 92.36%). Furthermore, strain SB2-23 significantly increased plant weight, root weight, root length, and diameter. Likewise, it improves sucrose percentage and juice purity. As a consequence, the strain SB2-23's intriguing biocontrol capability and sugar beet root growth stimulation present promising prospects for its utilization in both plant protection and enhancement strategies.

Development of Recombinase Polymerase Amplification-Lateral Flow Dipstick (RPA-LFD) as a Rapid On-Site Detection Technique for Fusarium oxysporum

Fusarium oxysporum can cause many important plant diseases worldwide, such as crown rot, wilt, and root rot. During the development of strawberry crown rot, this pathogenic fungus spreads from the mother plant to the strawberry seedling through the stolon, with obvious characteristics of latent infection. Therefore, the rapid and timely detection of F. oxysporum can significantly help achieve effective disease management. Here, we present a protocol for the recombinase polymerase amplification- lateral flow dipstick (RPA-LFD) detection technique for the rapid detection of F. oxysporum on strawberry, which only takes half an hour. A significant advantage of our RPA-LFD technique is the elimination of the involvement of professional teams and laboratories, which qualifies it for field detection. We test this protocol directly on plant samples with suspected infection by F. oxysporum in the field and greenhouse. It is worth noting that this protocol can quickly, sensitively, and specifically detect F. oxysporum in soils and plants including strawberry. Key features • This protocol is used to detect whether plants such as strawberry are infected with F. oxysporum. • This protocol has potential for application in portable nucleic acid detection. • It can complete the detection of samples in the field within 30 min.

Genome-Wide Identification and Expression Analysis of Chitinase Genes in Watermelon under Abiotic Stimuli and Fusarium oxysporum Infection

Chitinases, which catalyze the hydrolysis of chitin, the primary components of fungal cell walls, play key roles in defense responses, symbiotic associations, plant growth, and stress tolerance. In this study, 23 chitinase genes were identified in watermelon (Citrullus lanatus [Thunb.]) and classified into five classes through homology search and phylogenetic analysis. The genes with similar exon-intron structures and conserved domains were clustered into the same class. The putative cis-elements involved in the responses to phytohormone, stress, and plant development were identified in their promoter regions. A tissue-specific expression analysis showed that the ClChi genes were primarily expressed in the roots (52.17%), leaves (26.09%), and flowers (34.78%). Moreover, qRT-PCR results indicate that ClChis play multifaceted roles in the interaction between plant/environment. More ClChi members were induced by Race 2 of Fusarium oxysporum f. sp. niveum, and eight genes were expressed at higher levels on the seventh day after inoculation with Races 1 and 2, suggesting that these genes play a key role in the resistance of watermelon to Fusarium wilt. Collectively, these results improve knowledge of the chitinase gene family in watermelon species and help to elucidate the roles played by chitinases in the responses of watermelon to various stresses.

Transcriptomic-Proteomic Analysis Revealed the Regulatory Mechanism of Peanut in Response to Fusarium oxysporum

Peanut Fusarium rot, which is widely observed in the main peanut-producing areas in China, has become a significant factor that has limited the yield and quality in recent years. It is highly urgent and significant to clarify the regulatory mechanism of peanuts in response to Fusarium oxysporum. In this study, transcriptome and proteome profiling were combined to provide new insights into the molecular mechanisms of peanut stems after F. oxysporums infection. A total of 3746 differentially expressed genes (DEGs) and 305 differentially expressed proteins (DEPs) were screened. The upregulated DEGs and DEPs were primarily enriched in flavonoid biosynthesis, circadian rhythm-plant, and plant-pathogen interaction pathways. Then, qRT-PCR analysis revealed that the expression levels of phenylalanine ammonia-lyase (PAL), chalcone isomerase (CHI), and cinnamic acid-4-hydroxylase (C4H) genes increased after F. oxysporums infection. Moreover, the expressions of these genes varied in different peanut tissues. All the results revealed that many metabolic pathways in peanut were activated by improving key gene expressions and the contents of key enzymes, which play critical roles in preventing fungi infection. Importantly, this research provides the foundation of biological and chemical analysis for peanut disease resistance mechanisms.

A microbial bioherbicide for Striga hermonthica control: production, development, and effectiveness of a seed coating agent

Witchweed (Striga hermonthica), also called striga, is a parasitic weed that causes high yield losses in maize on more than 200 000 ha in Kenya alone. A new commercial, biological herbicide developed in Kenya is able to control striga effectively. The product was approved for use by the Pest Control Products Board in Kenya in September, 2021. It is self-produced in villages using a secondary inoculum provided by a commercial company. The formulated product has some disadvantages, which are a complicated production process, a very short shelf life and high application rate. Additionally, the product has to be applied manually and therefore can only be used in manual production, leaving out the opportunity for farmers using mechanization. For this reason, efforts have been made to formulate the active ingredient Fusarium oxysporum f. sp. strigae strain DSM 33471, as a powder and to use it as a seed coating agent. This article deals with the production of the Fusarium spore powder, its properties, its application to the seed, and its herbicidal effect demonstrated in the first two field trials. The F. oxysporum strain was originally isolated from a wilting striga plant in Kenya. The strain was virulence enhanced to over produce the amino acids leucine, methionine and tyrosine. These amino acids are responsible for a second mode of action apart from the wilting causing effect of the fungus on striga. Whereas leucine and tyrosine have a herbicidal effect, ethylene from methionine triggers the germination of striga seeds in the soil. Additionally, the strain has been improved to be resistant to the fungicide captan, which is commonly used to treat maize seed in Kenya. Seed coating tests conducted on 25 striga-infested small holder farms spread out in six counties of western Kenya reported yield increases of up to 88%. A second trial carried out by the Kenyan Agricultural and Livestock Research Organization showed a 93% reduction of emerged striga plants. © 2023 Society of Chemical Industry.

Genome-wide identification of the glutamate receptor-like gene family in Vanilla planifolia and their response to Fusarium oxysporum infection

Glutamate receptor-like genes (GLRs) are essential for plant growth and development and for coping with environmental (biological and non-biological) stresses. In this study, 13 GLR members were identified in the Vanilla planifolia genome and attributed to two subgroups (Clade I and Clade III) based on their physical relationships. Cis-acting element analysis and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations indicated the GLR gene regulation's complexity and their functional diversity. Expression analysis revealed a relatively higher and more general expression pattern of Clade III members compared to the Clade I subgroup in tissues. Most GLRs showed significant differences in expression during Fusarium oxysporum infection. This suggested that GLRs play a critical role in the response of V. planifolia to pathogenic infection. These results provide helpful information for further functional research and crop improvement of VpGLRs.

Benzalkonium Chloride and Benzethonium Chloride Effectively Reduce Spore Germination of Ginger Soft Rot Pathogens: Fusarium solani and Fusarium oxysporum

Ginger soft rot is a serious soil-borne disease caused by Fusarium solani and Fusarium oxysporum, resulting in reduced crop yields. The application of common chemical fungicides is considered to be an effective method of sterilization, and therefore, they pose a serious threat to the environment and human health due to their high toxicity. Benzalkonium chloride (BAC) and benzethonium chloride (BEC) are two popular quaternary ammonium salts with a wide range of fungicidal effects. In this study, we investigated the fungicidal effects of BAC and BEC on soft rot disease of ginger as alternatives to common chemical fungicides. Two soft rot pathogens of ginger were successfully isolated from diseased ginger by using the spread plate method and sequenced as F. solani and F. oxysporum using the high-throughput fungal sequencing method. We investigated the fungicidal effects of BAC and BEC on F. solani and F. oxysporum, and we explored the antifungal mechanisms. Almost complete inactivation of spores of F. solani and F. oxysporum was observed at 100 mg/L fungicide concentration. Only a small amount of spore regrowth was observed after the inactivation treatment of spores of F. solani and F. oxysporum in soil, which proved that BAC and BEC have the potential to be used as an alternative to common chemical fungicides for soil disinfection of diseased ginger.

Antifungal Peptide P852 Effectively Controls Fusarium oxysporum, a Wilt-Causing Fungus, by Affecting the Glucose Metabolism and Amino Acid Metabolism as well as Damaging Mitochondrial Function

Fusarium oxysporum causes wilt disease, which causes huge economic losses to a wide range of agricultural cash crops. Antifungal peptide P852 is an effective biocide. However, the mechanism of direct inhibition of pathogenic fungus needs to be explored. The proteomics and transcriptomics results showed that P852 mainly affected intracellular pathways such as glucose metabolism, amino acid metabolism, and oxidoreductase activity in F. oxysporum. P852 disrupts the intracellular oxidative equilibrium in F. oxysporum, and transmission electron microscopy observed mitochondrial swelling, disruption of membrane structure, and leakage of contents. Decreased mitochondrial membrane potential, mitochondrial cytochrome c leakage, and reduced ATP production were also detected. These results suggest that P852 is able to simultaneously inhibit intracellular metabolism and disrupt the mitochondrial function of F. oxysporum, exerting its inhibitory effects in multiple pathways together. The present study provides some insights into the multitargeted mechanism of fungus inhibition of antifungal lipopeptide substances produced by Bacillus spp.

Biocontrol fungi induced stem-base rot disease resistance of Morinda officinalis How revealed by transcriptome analysis

Introduction

Morinda officinalis How (MO) is a Rubiaceae plant, and its medicinal part is dried root, which is one of the "Four Southern Medicines" in China. At present, the plant MO breed seedlings mainly by cutting methods. Long-term asexual propagation makes pathogenic fungi accumulate in MO, leading to stem-base rot, which is caused by Fusarium oxysporum (Fon).

Methods

In this study, we used Trichoderma harzianum and Pestalotiopsis sp. as biocontrol fungi to investigate their antagonistic ability to Fon through in vitro antagonism and pot experiments, and combined with transcriptome sequencing to explore the mechanism of biocontrol.

Results

The results showed that both Trichoderma harzianum and Pestalotiopsis sp. could inhibit the growth of Fon. In addition, Trichoderma harzianum and Pestalotiopsis sp. could also enhance the basic immunity to Fon by increasing the activities of defensive enzymes such as POD and SOD, chlorophyll content, soluble sugar content, and oligosaccharide content of MO. The mechanism of biological control of stem-base rot of MO was discussed by transcriptome technology. MO was treated with two treatments, root irrigation with biocontrol fungi or inoculation with Fon after root irrigation with biocontrol fungi. Transcriptome sequencing revealed that nearly 11,188 differentially expressed genes (DEGs) were involved in the process of inducing MO systemic resistance to Fon by biocontrol fungi. Meanwhile, Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, as well as transcription factor (TFs) prediction showed that there were significant differences in the expression levels of MO roots under different treatments. Also, the genes of the "MAPK signaling pathway" and "plant hormone signaling pathway" were analyzed, in which the ERFs gene of the ethylene signal transduction pathway participated in the metabolism of glycosyl compounds. It is speculated that the ethylene signal may participate in the immune response of the sugar signal to the infection of Fon. After qRT-PCR verification of 10 DEGs related to the ethylene signal transduction pathway, the expression trend is consistent with the results of transcriptome sequencing, which proves the reliability of transcriptome sequencing.

Discussion

In conclusion, this study preliminarily identified the molecular mechanism of the biological control of MO stem-base rot and provided a scientific basis for further research on the prevention and control mechanism of MO stem-base rot.

Larvicidal and Fungicidal Activity of the Leaf Essential Oil of Five Myrtaceae Species

Myrtaceae is one of the most diverse and abundant botanical families, exhibiting wide diversity in the chemical composition of essential oils (EOs). EOs have various biotechnological applications such as controlling the populations of organisms that negatively impact humans. This study aimed to extract EOs from Myrtaceae species, chemically characterize them, and evaluate their larvicidal and fungicidal effects. EOs were extracted from the leaves of Eugenia brasiliensis, Eugenia uniflora, Psidium cattleyanum, Psidium guajava, and Syzygium cumini by hydrodistillation for 3 h and characterized by chromatographic analysis. Larvaes of Aedes aegypti and colonies of Fusarium oxysporum were subjected to increasing EO concentrations to determine the larvicidal and fungicidal potential. The EOs of Eugenia and Psidium species are primarily composed of sesquiterpenes (>80 %), whereas S. cumini EO is rich in monoterpenes (more than 60 %). The Eugenia species had similar amounts of oxygenated monoterpenes, which may explain their higher larvicidal potential compared to other species, with CL50 of 86.68 and 147.46 PPM, respectively. In addition to these two study species, S. cumini showed a high inhibition of fungal growth, with more than 65 % inhibition. We demonstrated that the actions of five EOs from Myrtaceae with different biological activities are associated with chemical diversity.

Synergistic benefits of Funneliformis mosseae and Bacillus paramycoides: Enhancing soil health and soybean tolerance to root rot disease

To explore the response of soil metabolite composition to soybean disease, the effect of the combined inoculation of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria on soybean root rot caused by Fusarium oxysporum was studied. A factorial completely randomized design with three factors (AMF, Bacillus. paramycoides, and rot disease stress) was conducted, and eight treatments, including normal groups and stress groups, were performed using pot experiments. GC‒MS and enzymatic assays were used to evaluate the soil factors and soybean growth indicators. The results showed that there were significant differences in the composition of metabolites among the different treatment groups, and 23 metabolites were significantly related to soybean biomass. The combined inoculation of Funneliformis mosseae and Bacillus paramycoides resulted in a significant reduction in harmful soil metabolites associated with root rot disease, such as ethylbenzene and styrene. This reduction in metabolites contributed to improving soil health, as evidenced by enhanced soybean defence enzyme activities and microbial activity, and β-1,3-glucanase, chitinase and phenylalanine ammonia-lyase activities were improved to alleviate plant rhizosphere stress. Furthermore, soybean plants inoculated with the synergistic treatments exhibited reduced root rot disease severity and improved growth indicators compared to control plants. Plant height, root dry weight (RDW), and shoot and root fresh weight (SRFW) were improved by 4.18-53.79%, and the AM fungal colonization rate was also improved under stress. The synergistic application of Funneliformis mosseae and Bacillus paramycoides can effectively enhance soil health by inhibiting the production of harmful soil metabolites and improving soybean tolerance to root rot disease. This approach holds promise for the sustainable management of soil-borne diseases in soybean cultivation.

Biological Control of Fusarium oxysporum, the Causal Agent of Fusarium Basal Rot in Onion by Bacillus spp

Fusarium oxysporum is the main pathogen causing Fusarium basal rot in onion (Allium cepa L.), which incurs significant yield losses before and after harvest. Among management strategies, biological control is an environmentally safe and sustainable alternative to chemical control. In this study, we isolated and screened bacteria for antifungal activity against the basal rot pathogen F. oxysporum. Isolates 23-045, 23-046, 23-052, 23-055, and 23-056 significantly inhibited F. oxysporum mycelial growth and conidial germination. Isolates 23-045, 23-046, 23-052, and 23-056 suppressed the development of Fusarium basal rot in both onion seedlings and bulbs in pot and spray inoculation assays. Isolate 23-055 was effective in onion seedlings but exhibited weak inhibitory effect on onion bulbs. Based on analyses of the 16S rRNA and rpoB gene sequences together with morphological analysis, isolates 23-045, 23-046, 23-052, and 23-055 were identified as Bacillus thuringiensis, and isolate 23-056 as Bacillus toyonensis. All five bacterial isolates exhibited cellulolytic, proteolytic, and phosphate-solubilizing activity, which may contribute to their antagonistic activity against onion basal rot disease. Taken together B. thuringiensis 23-045, 23-046, 23-052, and 23-055 and B. toyonensis 23-056 have potential for the biological control of Fusarium basal rot in onion.

Unraveling the Role of Cytochrome P450 as a Key Regulator Lantipeptide Production in Streptomyces globisporus

The aim of this study was to investigate the regulation of lantipeptide production in Streptomyces globisporus SP6C4, which produces the novel antifungal lantipeptides conprimycin and grisin, and to identify the role of cytochrome P450 (P450) in tis regulation. To investigate the regulation of lantipeptide production, we created gene deletion mutants, including ΔP450, ΔtsrD, ΔlanM, ΔP450ΔtsrD, and ΔP450ΔlanM. These mutants were characterized in terms of their morphology, sporulation, attachment, and antifungal activity against Fusarium oxysporum. The gene deletion mutants showed distinct characteristics compared to the wild-type strain. Among them, the ΔP450ΔlanM double mutant exhibited a recovery of antifungal activity against F. oxysporum, indicating that P450 plays a significant role in regulating lantipeptide production in S. globisporus SP6C4. Our findings highlight the significant role of P450 in the regulation of lantipeptide production and morphological processes in S. globisporus. The results suggest a potential link between P450-mediated metabolic pathways and the regulation of growth and secondary metabolism in SP6C4, thereby highlighting P450 as a putative target for the development of new antifungal agents.

Genomic Insights into the Microbial Agent Streptomyces albidoflavus MGMM6 for Various Biotechnology Applications

Microbial biotechnology plays a crucial role in improving industrial processes, particularly in the production of compounds with diverse applications. In this study, we used bioinformatic approaches to analyze the genomic architecture of Streptomyces albidoflavus MGMM6 and identify genes involved in various metabolic pathways that have significant biotechnological potential. Genome mining revealed that MGMM6 consists of a linear chromosome of 6,932,303 bp, with a high G+C content of 73.5%, lacking any plasmid contigs. Among the annotated genes, several are predicted to encode enzymes such as dye peroxidase, aromatic ring-opening dioxygenase, multicopper oxidase, cytochrome P450 monooxygenase, and aromatic ring hydroxylating dioxygenases which are responsible for the biodegradation of numerous endogenous and xenobiotic pollutants. In addition, we identified genes associated with heavy metal resistance, such as arsenic, cadmium, mercury, chromium, tellurium, antimony, and bismuth, suggesting the potential of MGMM6 for environmental remediation purposes. The analysis of secondary metabolites revealed the presence of multiple biosynthesis gene clusters responsible for producing compounds with potent antimicrobial and metal-chelating activities. Furthermore, laboratory tests conducted under controlled conditions demonstrated the effectiveness of MGMM6 in inhibiting phytopathogenic microbes, decolorizing and degrading aromatic triphenylmethane dyes, particularly Blue Brilliant G250, from wastewater by up to 98 ± 0.15%. Overall, the results of our study highlight the promising biotechnological potential of S. albidoflavus MGMM6.

Soil-borne fungi alter the apoplastic purinergic signaling in plants by deregulating the homeostasis of extracellular ATP and its metabolite adenosine

Purinergic signaling activated by extracellular nucleotides and their derivative nucleosides trigger sophisticated signaling networks. The outcome of these pathways determine the capacity of the organism to survive under challenging conditions. Both extracellular ATP (eATP) and Adenosine (eAdo) act as primary messengers in mammals, essential for immunosuppressive responses. Despite the clear role of eATP as a plant damage-associated molecular pattern, the function of its nucleoside, eAdo, and of the eAdo/eATP balance in plant stress response remain to be fully elucidated. This is particularly relevant in the context of plant-microbe interaction, where the intruder manipulates the extracellular matrix. Here, we identify Ado as a main molecule secreted by the vascular fungus Fusarium oxysporum. We show that eAdo modulates the plant's susceptibility to fungal colonization by altering the eATP-mediated apoplastic pH homeostasis, an essential physiological player during the infection of this pathogen. Our work indicates that plant pathogens actively imbalance the apoplastic eAdo/eATP levels as a virulence mechanism.

Dual Functions of a Hybrid Magnetic Magnesium Oxide Nanocomposite as a Fungicide and Plant Growth Promoter in Agriculture Applications

The use of nanometal oxides in nanoagronomy has garnered considerable attention due to their excellent antifungal and plant growth promotion properties. Hybrid nanometal oxides, which combine the strengths of individual nanomaterials, have emerged as a promising class of materials. In this study, nanomagnesium oxide (n-MgO) and hybrid magnetic nanomagnesium oxide (m/n-MgO) were successfully synthesized via the ultrasound-mediated sol-gel method. Characterization results, including TGA, XRD, VSM, and FTIR, confirmed the successful synthesis of m/n-MgO. Both n-MgO and m/n-MgO underwent antifungal assays and plant growth promotion ability studies, benchmarked against the conventional fungicide-copper oxychloride. This study bridges a significant gap by simultaneously reporting the antifungal properties of both n-MgO and m/n-MgO and their impact on plant growth. The disc diffusion assay suggested that the antifungal activity of n-MgO and m/n-MgO against F. oxysporum was inversely related to the particle size. Notably, n-MgO exhibited superior antifungal performance (lower minimum inhibitory concentration (MIC)) and sustained efficacy compared with m/n-MgO, owing to distinct antifungal mechanisms. Nanorod-shaped MgO, with a smaller size (8.24 ± 5.61 nm) and higher aspect ratio, allowed them to penetrate the fungal cell wall and cause intercellular damage. In contrast, cubical m/n-MgO, with a larger size (20.95 ± 9.99 nm) and lower aspect ratio, accumulate on the fungal cell wall surface, disrupting the wall integrity, albeit less effectively against F. oxysporum. Moreover, in plant growth promotion studies, m/n-MgO-treated samples exhibited a 15.7% stronger promotion effect compared to n-MgO at their respective MICs. In addition, both n-MgO and m/n-MgO outperformed copper oxychloride in terms of antifungal and plant growth promoting activities. Thus, m/n-MgO presents a promising alternative to conventional copper-based fungicides, offering dual functionality as a fungicide and plant growth promoter, while the study also delves into the antifungal mechanisms at the intracellular level, enhancing its novelty.

Development of a multiplex PCR assay for the detection of tomato wilt caused by co-infection of Fusarium brachygibbosum, Fusarium oxysporum, and Ralstonia solanacearum based on comparative genomics

Tomato is widely consumed worldwide as fresh or processed food products. However, soil-borne diseases of tomato plants caused by co-infection of various pathogens result in great economic losses to the tomato industry. It is difficult to accurately identify and diagnose soil-borne diseases of tomato plants caused by pathogen complexes. In this study, we investigated field diseases of tomato plants by pathogen isolation and molecular identification and found that tomato wilt was caused by co-infection of Fusarium brachygibbosum, Fusarium oxysporum, and Ralstonia solanacearum. Therefore, the development of a method for simultaneous detection of DNA from Fusarium brachygibbosum, Fusarium oxysporum, and Ralstonia solanacearum can efficiently and accurately monitor disease development at different growth stages of tomato plants. In this study, we performed a comparative genomic analysis of Fusarium brachygibbosum, Fusarium oxysporum, and Ralstonia solanacearum, and determined the primer sets for simultaneous detection of DNA from these target pathogens. Then, we tested the reagent and condition parameters of multiplex PCR, including primers, dNTP and Mg2+ concentrations, and the annealing temperatures, to determine the optimal parameters of a multiplex PCR system. We evaluated the specificity, sensitivity and stability of the multiplex PCR system based on the optimized reaction conditions. The multiplex PCR system can specifically identify 13 target pathogens from 57 different fungal and bacterial pathogens, at the lower detection limit of the three target pathogens at concentrations of 100pg/ul. In addition, we can accurately identify the three pathogens in tomato plants using the optimized multiplex PCR method. These results demonstrated that the multiplex PCR method developed in this study can simultaneously detect DNA from Fusarium brachygibbosum, Fusarium oxysporum, and Ralstonia solanacearum in a single PCR to accurately identify and diagnose the pathogen causing tomato wilt.

Natural product osthole can significantly disrupt cell wall integrity and dynamic balance of Fusarium oxysporum

Dendrobium officinale Kimura et Migo is a traditional Chinese herbal medicinal plant. However, the frequent occurrence of soft rot disease (SRD) is one of the most harmful diseases in D. officinale production in recent years, which can seriously affect its yield and quality. In this study, the major pathogenic fungus (SR-1) was isolated from D. officinale with typical symptoms of SRD, and was identified as Fusarium oxysporum through morphological and molecular identification. The biological activities of five natural products were determined against F. oxysporum using a mycelial growth inhibition assay. The results showed that osthole had the highest antifungal activity against F. oxysporum, with an EC50 value of 6.40 mg/L. Scanning electron microscopy (SEM) showed that osthole caused F. oxysporum mycelia to shrink and deform. Transmission electron microscopy (TEM) showed that the organelles were blurred and the cell wall was thickened in the presence of osthole. The sensitivity of F. oxysporum to calcofluor white (CFW) staining was significantly enhanced by osthole. Relative conductivity measurements and propidium iodide (PI) observation revealed that osthole had no significant effect on the cell membrane. Further experiments showed that the activity of chitinase and β-1,3-glucanase were decreased, and expression levels of chitinase and β-1,3-glucanase related genes were significantly down-regulated after treatment with osthole. In conclusion, osthole disrupted the cell wall integrity and dynamic balance of F. oxysporum, thereby inhibiting normal mycelial growth.

fabae and cinnamic acid stress in faba bean-wheat intercropping system and underlying proteomic mechanisms

Continuous cropping severely affects faba bean growth, mainly due to pathogen and autotoxic substance accumulation. Here, we used faba bean monocropping (M) and intercropping with wheat (I), with stress treatments of Fusarium oxysporum f. sp. fabae (FOF) alone (F) and combined with cinnamic acid (F + C), to analyze seedling growth, defense-related enzymes, levels of resistance-associated substances, and protein expression profiles in roots. The results showed that intercropping mitigated the inhibitory effects of FOF and cinnamic acid. FOF resulted in increased activities of defense-related enzymes as well as levels of resistance-associated substances. Proteomic analysis showed that 22 proteins were upregulated following FOF inoculation (M + F), and 6 proteins were downregulated after the addition of cinnamic acid (M + F + C) in monocropping plants; these proteins were mainly involved in pathways associated with carbohydrate metabolism, energy, and the cytoplasm. Comparison of monocropping and intercropping indicated that the upregulated proteins were mostly associated with stress and defense, carbohydrate transport and metabolism, maintenance of cellular homeostasis, and protein synthesis. KEGG analysis revealed that intercropping increased enrichment in pathways associated with metabolism, ribosomes, biosynthesis of secondary metabolites, proteasomes, pyruvate metabolism, and pentose and glucuronate interconversions. The results indicated that intercropping mitigated growth inhibition by FOF and cinnamic acid by increasing energy production, maintaining normal cellular functions, and promoting the synthesis of defense-associated secondary metabolites. These findings provide a basis for further investigation into the molecular mechanisms underlying the effects of intercropping in controlling resistance to Fusarium wilt in the faba bean.

lycopersici

Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies.

First report of Root rot in Cerasus subhirtella Caused by Fusarium solani and Fusarium oxysporum in China

Cerasus subhirtella (Miq.) Sok. is a widely used ornamental tree in urban areas around China and has a high ornamental value. From 2018 to 2020, a root rot disease was observed in C. subhirtella in Meitan County, Weng'an County, and Guiyang city of Guizhou, China (106.71 E, 26.57 N). Diseased C. subhirtella trees exhibited wilting with leaf chlorosis accompanied by brown to black root discoloration. In an area of 100 ha in total, with disease incidence ranging from 60 to 80%. Six symptomatic plants with root rot were randomly collected from three locations where disease symptoms were observed for pathogen isolation. Fifty fragments of diseased roots (5×5mm) were disinfected in 3% sodium hypochlorite for 30 s and 75% alcohol for 60 s, rinsed three times in sterile distilled water, plated on potato dextrose agar (PDA; BoWei, Shanghai), and incubated at 28 °C in the dark for 7 days. Eighteen isolates were purified by single spore culturing. Typical Fusarium spp. colonies were obtained from all root samples. On PDA, the colonies showed white and the hyphae were dense, while the colony of isolate YH15 showed pale yellow on the back, radial growth and produced chlamydospores. The macrospores (YH15) were straight to subarcuate, measured 15.3 to 25.1 × 2.5 to 6.2 μm (n=50). The microconidia (YH26) were ellipsoid to ovoid, measured 8.6 to 12.7 × 1.6 to 5.1 μm (n=50). These morphological characteristics were consistent with Fusarium spp., as described recently in Vitullo et al. (2014). To confirm the morphological diagnosis, genomic DNA from the isolates was extracted. The internal transcribed spacer (ITS) (White et al, 1990) region of rDNA and a β-tubulin (Varga et al, 2011) gene fragment were amplified with the primers ITS1/ITS4 and Bt2a/Bt2b, respectively, and were subsequently sequenced. Maximum likelihood analysis was carried out using MEGA 11.0. BLAST analysis revealed that the ITS and β-tubulin sequences of isolate YH15 were 100% homologous with F. oxysporum, and the isolate YH26 had a 99.69~100% homology with F. solani. Sequences of isolate YH15 and YH26 were deposited in GenBank (ITS: OQ363005 and OQ363049; β-tubulin: OQ398187 and OQ398180). The isolate YH15 was thus identified as F. oxysporum by the morphological characteristics and sequences analysis, and the isolate YH26 was identified as F. solani. A reconstructed phylogenetic tree also confirmed their phylogenetic position. The healthy 2-year-old C. subhirtella plants grown in autoclaved acid yellow soil were used for the pathogenicity tests. Then, 50 mL of conidial suspension (2.0×105 conidia/mL, in medium) of 7-day-old isolates YH15 and YH26 were gently applied to the soil in each of the 10 pots as the treatment. A sterilized fungal culture matrix (PDB; BoWei, Shanghai) was applied to each of 10 pots as a control. All pots (30 cm high, 25 cm upper diameter, 15 cm base diameter) were placed in a greenhouse (25 °C, 12 h photoperiod). After 30 days of inoculation, all plants inoculated with the isolates showed wilting symptoms, and the roots showed light-brown to dark-brown lesions. No symptoms were observed in the controls. The pathogen was reisolated from all symptomatic roots and identified as F. oxysporum and F. solani as described above. The pathogenicity test was repeated twice with similar results. Although this fungus was previously reported to cause root disease in many hosts (Li et al., 2020; Gibert et al., 2022), this is the first report of F. oxysporum and F. solani causing root rot in C. subhirtella in China.

Identification and Chemical and Biological Management of Fusarium Root and Crown Rot Disease of Oakleaf Hydrangea

Oakleaf hydrangea (Hydrangea quercifolia) is an important ornamental plant grown in Tennessee. In May 2018, after late spring frost, cultivars Pee Wee and Queen of Hearts showed root and crown rot symptoms and identification and management of the disease was a major concern. The objective of this research was to identify the causal organism of this disease and develop management recommendations for nursery growers. Isolates from the infected root and crown parts were subjected to microscopy, and the morphology of fungi resembled Fusarium. Molecular analysis was conducted by amplifying the internal transcribed spacer of ribosomal DNA, β-tubulin, and translation elongation factor 1-α regions. Fusarium oxysporum was identified as a causal organism based on molecular analysis. A pathogenicity test was done to complete the Koch's postulates by drenching containerized oakleaf hydrangea with a conidial suspension. Experiments were conducted to evaluate different chemical fungicides and biological products with different rates for Fusarium root and crown rot management in container-grown Queen of Hearts. Plants were inoculated by drenching containerized oakleaf hydrangea with 150-ml conidial suspensions of F. oxysporum, maintaining the concentration of 1 × 106 conidia/ml. Root and crown rot were assessed using a scale of 0 to 100%. Recovery of F. oxysporum was recorded by plating root and crown sections. Chemical fungicides such as mefentrifluconazole (BAS75002F), the low rate (1.09 ml/liter) of difenoconazole + pydiflumetofen (Postiva), and the high rate (1.32 ml/liter) of isofetamid (Astun) and biopesticide were applied; the high rate (1.64 g/liter) of ningnanmycin (SP2700 WP) effectively reduced Fusarium root rot severity and pyraclostrobin effectively reduced Fusarium crown rot severity in both trials.

Detection of Fungal Diseases in Lettuce by VIR-NIR Spectroscopy in Aquaponics

One of the main challenges facing the development of aquaponics is disease control, due on one hand to the fact that plants cannot be treated with chemicals because they can lead to mortality in cultured fish. The aim of this study was to apply the visible-near-infrared spectroscopy and vegetation index approach to test aquaponically cultivated lettuce (Lactuca sativa L.) infected with different fungal pathogens (Aspergillus niger, Fusarium oxysporum, and Alternaria alternata). The lettuces on the third leaf formation were placed in tanks (with dimensions 1 m/0.50 m/0.35 m) filled up with water from the aquaponics system every second day. In this study, we included reference fungal strains Aspergillus niger NBIMCC 3252, Fusarium oxysporum NBIMCC 125, and Alternaria alternata NBIMCC 109. Diffuse reflectance spectra of the leaves of lettuce were measured directly on the plants using a USB4000 spectrometer in the 450-1100 nm wavelength range. In near-infrared spectral range, the reflectance values of infected leaves are lower than those of the control, which indicates that some changes in cell structures occurred as a result of the fungal infection. All three investigated pathogens had a statistically significant effect on leaf water content and water band index. Vegetative indices such as Chlorophyll Absorption in Reflectance Index (CARI), Modified chlorophyll absorption in reflectance index (MCARI), Plant Senescence Reflectance Index (PSRI), Red Edge Index (REI2), Red Edge Index (REI3), and Water band index (WBI) were found to be effective in distinguishing infected plants from healthy ones, with WBI demonstrating the greatest reliability.

spinaciae

Fusarium wilt of spinach, caused by Fusarium oxysporum f. sp. spinaciae, is a significant limitation for producers of vegetative spinach and spinach seed crops during warm temperatures and/or on acid soils. Identification of isolates of F. oxysporum f. sp. spinaciae, and distinction of isolates of the two known races, entails time-intensive pathogenicity tests. In this study, two real-time PCR assays were developed: one for a candidate effector gene common to both races of F. oxysporum f. sp. spinaciae, and another for a candidate effector gene unique to isolates of race 2. The assays were specific to isolates of F. oxysporum f. sp. spinaciae (n = 44) and isolates of race 2 (n = 23), respectively. Neither assay amplified DNA from 10 avirulent isolates of F. oxysporum associated with spinach, 57 isolates of other formae speciales and Fusarium spp., or 7 isolates of other spinach pathogens. When the assays were used to detect DNA extracted from spinach plants infected with an isolate of race 1, race 2, or a 1:1 mixture of both races, the amount of target DNA detected increased with increasing severity of wilt. Plants infected with one or both isolates could be distinguished based on the ratio in copy number for each target locus. The real-time PCR assays enable rapid diagnosis of Fusarium wilt of spinach and will facilitate research on the epidemiology and management of this disease, as well as surveys on the prevalence of this understudied pathogen in regions of spinach and/or spinach seed production.

Effect of green Fe2O3 nanoparticles in controlling Fusarium fruit rot disease of loquat in Pakistan

The subtropical fruit known as the loquat is prized for both its flavour and its health benefits. The perishable nature of loquat makes it vulnerable to several biotic and abiotic stressors. During the previous growing season (March-April 2021), loquat in Islamabad showed signs of fruit rot. Loquat fruits bearing fruit rot symptoms were collected, and the pathogen that was causing the disease isolated and identified using its morphology, microscopic visualisation, and rRNA sequence. The pathogen that was isolated was identified as Fusarium oxysporum. Green synthesized metallic iron oxide nanoparticles (Fe2O3 NPs) were employed to treat fruit rot disease. Iron oxide nanoparticles were synthesized using a leaf extract of the Calotropis procera. Characterization of NPs was performed by different modern techniques. Fourier transform infrared spectroscopy (FTIR) determined the existence of stabilizing and reducing compounds like phenol, carbonyl compounds, and nitro compounds, on the surface of Fe2O3 NPs. X-ray diffraction (XRD) explained the crystalline nature and average size (~49 nm) of Fe2O3 NPs. Energy dispersive X-ray (EDX) exhibited Fe and O peaks, and scanning electron microscopy (SEM) confirmed the smaller size and spherical shape of Fe2O3 NPs. Following both in vitro and in vivo approaches, the antifungal potential of Fe2O3 NPs was determined, at different concentrations. The results of both in vitro and in vivo analyses depicted that the maximum fungal growth inhibition was observed at concentration of 1.0 mg/mL of Fe2O3 NPs. Successful mycelial growth inhibition and significantly reduced disease incidence suggest the future application of Fe2O3 NPs as bio fungicides to control fruit rot disease of loquat.

Establishment of the Recombinase Polymerase Amplification-Lateral Flow Dipstick Detection Technique for Fusarium oxysporum

Fusarium oxysporum causes crown rot, wilt, root rot, and many other major plant diseases worldwide. During the progression of strawberry crown rot disease, the pathogen is transmitted from the mother plant to the seedling through the stolon, with obvious characteristics of latent infection. Therefore, rapid and timely detection of F. oxysporum is important for efficient disease management. In this study, a recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) detection technique was developed for the rapid detection of F. oxysporum on strawberry plants by targeting the CYP51C gene, which is unique to Fusarium spp. Because this RPA-LFD detection technique was highly specific to F. oxysporum, other Fusarium and non-Fusarium fungi were not detected. The optimal reaction temperature and time for this technique were 39°C and 8 min, respectively. The detection limit was 1 pg of F. oxysporum genomic DNA in a 50-μl reaction system. A total of 46 strawberry plants with or without crown rot symptoms collected from Jiande, Changxing, and Haining in Zhejiang Province were further assessed for F. oxysporum infection using both RPA-LFD and traditional tissue isolation techniques. The RPA-LFD test showed that 32 of the 46 strawberry plants tested were positive for F. oxysporum, while in the traditional isolation technique, F. oxysporum was isolated from 30 of the 46 strawberry plants. These results suggest that our established RPA-LFD method is rapid, sensitive, and highly specific in detecting F. oxysporum infection in strawberry plants.

The Impact of the Soil Survival of the Pathogen of Fusarium Wilt on Soil Nutrient Cycling Mediated by Microorganisms

Fusarium wilt of Momordica charantia in the greenhouse is one of the most severe crop diseases in Shandong Province, P.R. China. This study aimed to investigate the mechanisms of accumulation and long-term survival of the pathogen in naturally pathogenic soils. Soil physicochemical properties were tested after applying a highly virulent strain of Fusarium wilt to M. charantia in an artificial disease nursery. The functional structure of soil microorganisms was analyzed through amplicon sequencing. The highly virulent strain SG-15 of F. oxysporum f. sp. momordicae was found to cause Fusarium wilt in M. charantia in Shandong Province. The strain SG-15 could not infect 14 non-host crops, including Solanum melongena and Lycopersicon esculentum, but it had varying degrees of pathogenicity towards 11 M. charantia varieties. In the artificial disease nursery for Fusarium wilt of M. charantia, the F. oxysporum was distributed in the soil to a depth of 0-40 cm and was mainly distributed in crop residues at 0-10 cm depth. During crop growth, F. oxysporum primarily grows and reproduces in susceptible host plants, rather than disease-resistant hosts and non-host crops. The colonization of the pathogen of Fusarium wilt significantly changed the soil physicochemical properties, the functional structure of soil microorganisms and the circulation of soil elements such as carbon, nitrogen, phosphorus and sulfur. Soil pH value, organic matter content, available iron content, available manganese content, FDA hydrolase activity and polyphenol oxidase activity were significantly correlated with the relative abundance of Fusarium wilt pathogens in the soil. In general, this study suggests that susceptible host plants facilitate the accumulation of Fusarium wilt pathogens in the soil. These pathogens can mediate the decomposition process of plant residues, particularly those of diseased plants, and indirectly or directly affect soil's chemical properties.

Quorum Sensing-Dependent Invasion of Ralstonia solanacearum into Fusarium oxysporum Chlamydospores

Strains of the Ralstonia solanacearum species complex (RSSC), although known as the causative agent of bacterial wilt disease in plants, induce the chlamydospores of many fungal species and invade them through the spores. The lipopeptide ralstonins are the chlamydospore inducers produced by RSSC and are essential for this invasion. However, no mechanistic investigation of this interaction has been conducted. In this study, we report that quorum sensing (QS), which is a bacterial cell-cell communication, is important for RSSC to invade the fungus Fusarium oxysporum (Fo). ΔphcB, a deletion mutant of QS signal synthase, lost the ability to both produce ralstonins and invade Fo chlamydospores. The QS signal methyl 3-hydroxymyristate rescued these disabilities. In contrast, exogenous ralstonin A, while inducing Fo chlamydospores, failed to rescue the invasive ability. Gene-deletion and -complementation experiments revealed that the QS-dependent production of extracellular polysaccharide I (EPS I) is essential for this invasion. The RSSC cells adhered to Fo hyphae and formed biofilms there before inducing chlamydospores. This biofilm formation was not observed in the EPS I- or ralstonin-deficient mutant. Microscopic analysis showed that RSSC infection resulted in the death of Fo chlamydospores. Altogether, we report that the RSSC QS system is important for this lethal endoparasitism. Among the factors regulated by the QS system, ralstonins, EPS I, and biofilm are important parasitic factors. IMPORTANCE Ralstonia solanacearum species complex (RSSC) strains infect both plants and fungi. The phc quorum-sensing (QS) system of RSSC is important for parasitism on plants, because it allows them to invade and proliferate within the hosts by causing appropriate activation of the system at each infection step. In this study, we confirm that ralstonin A is important not only for Fusarium oxysporum (Fo) chlamydospore induction but also for RSSC biofilm formation on Fo hyphae. Extracellular polysaccharide I (EPS I) is also essential for biofilm formation, while the phc QS system controls these factors in terms of production. The present results advocate a new QS-dependent mechanism for the process by which a bacterium invades a fungus.