Assessing the In Vitro Individual and Combined Effect of Arthrobotrys oligospora and A. musiformis (Orbiliales) Liquid Culture Filtrates against Infective Larvae of the Sheep Blood-Feeding Nematode Haemonchus contortus (Trichostrongylidae).

BACKGROUND: Arthrobotrys species are nematophagous fungi that secrete extracellular nematocidal products (ECP). The individual and combined effects of ECP from Arthrobotrys oligospora (Ao) and A. musiformis (Am) growth in liquid media against Haemonchus contortus L3 (HcL3) were assessed. METHODS: The isolation, morphological (MI) and molecular identification (Mol-I), assessment of nematocidal activity (NA) of fungal liquid culture filtrates (LCF) in two liquid media alone and in combination and the myco-compound profile identification (MCP) were performed. RESULTS: The MI suggested that the fungi corresponded to the species Ao and Am. This result was confirmed by PCR analysis followed by sequencing, alignment and a phylogenetic analysis. Likewise, the highest Hc mortalities were 91.4% with individual LCF of Am and 86.2% with those of Ao at the highest concentration (100 mg/mL) in Czapek-Dox Broth. The combination of both LCF resulted in a similarly high larval mortality with no statistical differences in relation to individual activity (p > 0.05). The MCP showed the presence of alkaloids in both fungi. Coumarins, sterols and saponins were found only in Ao. MAIN CONCLUSIONS: Both fungi produced ECP with a high NA that could be identified and assessed in future studies as potential natural anthelmintic compounds.

Control of the plant-parasitic nematode Meloidogyne incognita in soil and on tomato roots by Clonostachys rosea.

AIMS: Clonostachys rosea is a well-known mycoparasite that has recently been investigated as a bio-based alternative to chemical nematicides for the control of plant-parasitic nematodes. In the search for a promising biocontrol agent, the ability of the C. rosea strain PHP1701 to control the southern root-knot nematode Meloidogyne incognita was tested. METHODS AND RESULTS: Control of M. incognita in vitro and in soil by C. rosea strain PHP1701 was significant and concentration dependent. Small pot greenhouse trials confirmed a significant reduction in tomato root galling compared to the untreated control. In a large greenhouse trial, the control effect was confirmed in early and mid-season. Tomato yield was higher when the strain PHP1701 was applied compared to the untreated M. incognita-infected control. However, the yield of non-M. incognita-infected tomato plants was not reached. A similar reduction in root galling was also observed in a field trial. CONCLUSIONS: The results highlight the potential of this fungal strain as a promising biocontrol agent for root-knot nematode control in greenhouses, especially as part of an integrated pest management approach. We recommend the use of C. rosea strain PHP1701 for short-season crops and/or to reduce M. incognita populations on fallow land before planting the next crop.

Linking the protease activity to the nematicidal action of edible mushroom.

Biological control using edible mushrooms as natural enemies is a sustainable alternative for pest management. Despite the well-established literature on toxins and secondary metabolites produced by these fungi in the biochemical control of nematodes, the nematicidal activity of proteases from different Pleurotus species is yet to be investigated. Therefore, this study aimed to correlate protease to the nematicidal activity of different mushrooms, Pleurotus sp., P. ostreatus (SB), P. ostreatus (Pearl), and P. djamor. For such a purpose, we performed motility assays of Panagrellus sp. at different time intervals, 6, 12, and 24 h for each of the mushrooms. In addition, the protease activity was measured using different pH (5, 7, and 9) and fermentation time intervals (45 and 75 days). Furthermore, we also evaluated the effect of this cell-free extract on Panagrellus sp. In response to these experiments, all edible mushrooms showed a reduction over 82% for the nematode-feeding activity (p < 0.01). The cell-free crude extract of each of the fungi studied showed nematocidal activity (p < 0.01). For the 45-day fermentation, P. djamor exhibited statistical significance (p < 0.01) compared with the others, reaching a reduction percentage of 73%. For the 75-day fermentation, Pleurotus sp. and P. ostreatus (Pearl) showed significant differences compared with the other fungi (p < 0.01), with reduction percentages of 64 and 62%, respectively. Herein, protease activity was associated with the nematicidal action of different Pleurotus species in controlling Panagrellus sp.

Assessing the applications and efficacy of using helminthophagous fungi to control canine gastrointestinal parasites.

Helminths are a major challenge in dog breeding, particularly affecting young animals and posing a significant zoonotic risk. The widespread use of anthelmintics to treat gastrointestinal helminth infections in companion animals is common. However, these chemical products generate residues that can have adverse effects on animal, human and environmental health. In addition to the challenge of parasite resistance to treatment, there is an urgent need to explore and discuss complementary and sustainable methods of controlling helminthiases in these animals. In this context, nematophagous or helminthophagous fungi have emerged as a potential tool for the control of environmental forms of helminths. The purpose of this review is to emphasize the importance of these fungi in the control of free-living forms of helminth parasites in companion animals by highlighting the research that has been conducted for this purpose. In vitro experiments demonstrated the efficacy of fungi like Pochonia chlamydosporia, Arthrobotrys robusta, and Monacrosporium thaumasium in trapping and reducing helminth infective forms. These findings, along with soil contamination studies, suggest the feasibility of using helminthophagous fungi as a sustainable and effective strategy for environmental control. The current literature supports the potential of these fungi as an environmentally friendly solution for managing helminthiasis in dogs, benefiting both animal health and public welfare.

Determination of cyclic adenosine phosphate and protein content in dormant chlamydospore and nondormant chlamydospore of Arthrobotrys flagrans.

Arthrobotrys flagrans, a nematode-eating fungus, is an effective component of animal parasitic nematode biocontrol agents. In the dried formulation, the majority of spores are in an endogenous dormant state. This study focuses on dormant chlamydospore and nondormant chlamydospore of A. flagrans to investigate the differences in cyclic adenosine monophosphate (cAMP) and protein content between the two types of spores. cAMP and soluble proteins were extracted from the nondormant chlamydospore and dormant chlamydospore of two isolates of A. flagrans. The cAMP Direct Immunoassay Kit and Bradford protein concentration assay kit (Coomassie brilliant blue method) were used to detect the cAMP and protein content in two types of spores. Results showed that the content of cAMP in dormant spores of both isolates was significantly higher than that in nondormant spores (p < 0.05). The protein content of dormant spores in DH055 bacteria was significantly higher than that of nondormant spores (p < 0.05). In addition, the protein content of dormant spores of the SDH035 strain was slightly higher than that of nondormant spores, but the difference was not significant (p > 0.05). The results obtained in this study provide evidence for the biochemical mechanism of chlamydospore dormancy or the germination of the nematophagous fungus A. flagrans.

Preparation and application of biocontrol formulation of nematode-trapping fungus-Duddingtonia flagrans.

The use of nematophagous fungi as a biological control strategy for parasitic gastrointestinal nematodes (GINs) in livestock holds promise as an innovative alternative approach. This study aimed to evaluate the clinical efficacy of a lyophilized Duddingtonia flagrans preparation, utilized in association with the anthelmintics ivermectin or albendazole, to control GINs in Tibetan sheep on a farm based in Qinghai Province. The experimental design included five groups: D. flagrans lyophilized preparation group; D. flagrans+ ivermectin combination tablets treatment group (0.6 tablets for each 10 kg b.w. containing 106 chlamydospores of D. flagrans); D. flagrans+ albendazole combination capsules treatment group (5 capsules for each 10 kg b.w. containing 106 chlamydospores of D. flagrans); ivermectin group (0.2 mg/kg); albendazole group (15 mg/kg), and a control group; The effect of these strategies was evaluated through the analysis of feces collected directly from the animals in each group at 24 h, 48 h, 72 h,96 h and 120 h after administration, by estimating the counts of fecal egg count reduction percentage (FECR) and larval development reduction percentage (LDR). The combination of D. flagrans lyophilized preparation with either ivermectin or albendazole yielded fecal egg and larval reduction rates of up to 100% within 72 h after oral administration, outperforming the groups treated with a single anthelmintic. Moreover, the application of the lyophilized preparation of D. flagrans chlamydospores in isolation demonstrated an 89.8% larval reduction rate. The formulation containing D. flagrans showed high predatory capacity after passage through the gastrointestinal tract of sheep and was effective for controlling gastrointestinal nematodes, which greatly reduced the pollution of the grassland, and avoid reinfection.

Microstructure characterization of different types of chlamydospores in Arthrobotrys flagrans.

The morphological and structural differences of different types of chlamydospore of Arthrobotrys flagrans, a nematophagous fungus, were studied under light microscope and electron microscope to provide a reference for the biological control of parasitic nematodiasis. In this study, A. flagrans isolate F088 dormant chlamydospore and nondormant chlamydospore were selected as the research objects. The structural differences of these spores were observed by optical microscopy through lactol cotton blue, Trypan blue, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) staining. FunXite -1, 4',6-diamidino-2-phenylindole, and calcofluor white staining were used to observe the metabolic activity, cell wall, and nucleus differences of the two types of spores under fluorescence microscope. Ultrastructure of the two kinds of spores was observed using scanning electron microscope (SEM) and transmission electron microscope (TEM). Since lacto phenol cotton blue, trypan blue staining cannot distinguish dormant spores from dead spores, MTT assay was performed. Fluorescence microscopy observation showed that the cytoplasmic metabolic activity of nondormant spores was stronger than that of dormant spores. The nucleus of dormant spores was bright blue, and their fluorescence was stronger than that of nondormant spores. The cell wall of nondormant spores produced stronger yellow-green fluorescence than that of dormant spores. Ultrastructural observation showed that there were globular protuberances on the surface of the two types of spores but with no significant difference between them. The inner wall of dormant spore possesses a thick zona pellucida with high electron density which was significantly thicker than that of nondormant spores, and their cytoplasm is also changed. In this study, the microstructure characteristics of dormant and nondormant chlamydospores of A. flagrans fungi were preliminarily clarified, suggesting that the state of cell wall and intracellular materials were changed after spores entered to dormancy.

Chitosan from Marine Amphipods Inhibits the Wilt Banana Pathogen Fusarium oxysporum f. sp. Cubense Tropical Race 4.

In this work, we extracted chitosan from marine amphipods associated with aquaculture facilities and tested its use in crop protection. The obtained chitosan was 2.5 ± 0.3% of initial ground amphipod dry weight. The chemical nature of chitosan from amphipod extracts was confirmed via Raman scattering spectroscopy and Fourier transform infrared spectroscopy (FTIR). This chitosan showed an 85.7-84.3% deacetylation degree. Chitosan from biofouling amphipods at 1 mg·mL-1 virtually arrested conidia germination (ca. sixfold reduction from controls) of the banana wilt pathogenic fungus Fusarium oxysporum f. sp cubense Tropical Race 4 (FocTR4). This concentration reduced (ca. twofold) the conidia germination of the biocontrol fungus Pochonia chlamydosporia (Pc123). Chitosan from amphipods at low concentrations (0.01 mg·mL-1) still reduced FocTR4 germination but did not affect Pc123. This is the first time that chitosan is obtained from biofouling amphipods. This new chitosan valorizes aquaculture residues and has potential for biomanaging the diseases of food security crops such as bananas.

Study of a Mexican isolate of Arthrobotrys musiformis (Orbiliales): Predatory behavior and nematocidal activity of liquid culture filtrates against Haemonchus contortus (Trichostrongylidae), protein profile and myco-constituent groups.

A Mexican isolate of the nematophagous fungus Arthrobotrys musiformis was obtained from a soil sample from the Chapultepec ecological reserve zone, in Cuernavaca, Morelos, Mexico. This isolate demonstrated an important predatory activity (74.9%) against the parasitic nematode Haemonchus contortus (L3) and its fungal liquid culture filtrates (LCF) grown in two media showed the following highest nematocidal activities (NA): In Czapek-DoxBroth (CzDoxB) 80.66% and potato-dextrose broth (PDB) 49.84%. Additionally, two major compounds derived from carboxylic acids and two derivates from alkane group were identified by GC-MS. These compounds have been associated to many biological activities. On the other hand, the protein profile analysis by SDS-electrophoresis followed by a zymogram revealed a 10 kDa protein with protease activity. This study provides important information for future experiments focused to explore the potential use of this protein as well as the identified bioactive compounds presents in the LCF as potential candidates against sheep haemonchosis.

Counter-attack of biocontrol agents: Environmentally benign Approaches against Root-knot nematodes (Meloidogyne spp.) on Agricultural crops.

Root-knot nematodes (Meloidogyne spp.) are obligate sedentary endoparasites, considered severe crop-damaging taxa among all plant-parasitic nematodes globally. Their attacks through parasitic proteins alter the physiology and machinery of the host cells to favour parasitism and reduction in crop yield. Currently, the use of excessive pesticides as a fast remedy to manage this pest is hazardous for both the environment and humans. Keeping this view in mind, there is an urgent need for developing efficient eco-friendly strategies. Bio-control as an eco-friendly is considered the best approach to manage nematodes without disturbing non-target microbes. In bio-control, living agents such as fungi and bacteria are the natural enemies of nematodes and the best substitute for pesticides. Fungi, including nematode-trapping fungi, can sense host signals and produce special trapping devices viz., constricting rings and adhesive knobs/loops, to capture nematodes and kill them. Whereas, endo-parasitic fungi kill nematodes by enzymatic secretions and spore adhesion through their hyphae. Bacteria can also control nematodes by producing antibiotic compounds, competing for nutrients and rhizosphere, production of hydrolytic enzymes viz., chitinases, proteases, lipases, and induction of systemic resistance (ISR) in host plants. Scientists throughout the world are trying to evolve environmentally benign methods that sustain agricultural production and keep nematodes below a threshold level. Whatever methods evolve, in the future the focus should be on important aspects like green approaches for managing nematodes without disturbing human health and the environment.

Compatibility study of Duddingtonia flagrans conidia and its crude proteolytic extract.

This study aimed to evaluate the concomitant use of the nematophagous fungus Duddingtonia flagrans (AC001) and its protease-rich crude extract for the in vitro control of Panagrellus sp., Haemonchus spp., and Trichostrongylus spp. The nematicidal tests were carried out on larvae of the free-living nematode Panagrellus sp. and infective larvae of the gastrointestinal parasitic nematodes of domestic ruminants (Haemonchus spp. and Trichostrongylus spp). Five experimental groups were set: (1) one control group (G1) and (4) four treated groups -G2 - active crude extract; G3 - denatured crude extract; G4 - fungus, and G5 - fungus + active extract. Plates were incubated at 28 ºC for 24 h followed by the recovery of the larvae using the Baermann technique. The results showed a lower recovery of Panagrellus sp. larvae in the experimental groups compared to the control group, as follows: 52 % (G2), 16 % (G3), 46 % (G4), and 77 % (G5). An even greater reduction (77 ± 5 %) occurred in the group (G5). In addition, the authors observed lower averages of L3 of Haemonchus spp. and Trichostrongylus spp. in the experimental groups compared to the control group, as follows: 59 % (G2), 0 % (G3), 86 % (G4), and 76 % (G5). In turn, there was a difference (p < 0.01) between (G5) and (G2). The results this study indicate a positive effect from the compatible use of the D. flagrans fungus and its enzymatic crude extract (protease), which has been demonstrated here for the first time and with potential field applications for further designs.

Ethanol mediates the interaction between Caenorhabditis elegans and the nematophagous fungus Purpureocillium lavendulum.

Accurately recognizing pathogens by the host is vital for initiating appropriate immune response against infecting microorganisms. Caenorhabditis elegans has no known receptor to recognize pathogen-associated molecular pattern. However, recent studies showed that nematodes have a strong specificity for transcriptomes infected by different pathogens, indicating that they can identify different pathogenic microorganisms. However, the mechanism(s) for such specificity remains largely unknown. In this study, we showed that the nematophagous fungus Purpureocillium lavendulum can infect the intestinal tract of the nematode C. elegans and the infection led to the accumulation of reactive oxygen species (ROS) in the infected intestinal tract, which suppressed fungal growth. Co-transcriptional analysis revealed that fungal genes related to anaerobic respiration and ethanol production were up-regulated during infection. Meanwhile, the ethanol dehydrogenase Sodh-1 in C. elegans was also up-regulated. Together, these results suggested that the infecting fungi encounter hypoxia stress in the nematode gut and that ethanol may play a role in the host-pathogen interaction. Ethanol production in vitro during fungal cultivation in hypoxia conditions was confirmed by gas chromatography-mass spectrometry. Direct treatment of C. elegans with ethanol elevated the sodh-1 expression and ROS accumulation while repressing a series of immunity genes that were also repressed during fungal infection. Mutation of sodh-1 in C. elegans blocked ROS accumulation and increased the nematode's susceptibility to fungal infection. Our study revealed a new recognition and antifungal mechanism in C. elegans. The novel mechanism of ethanol-mediated interaction between the fungus and nematode provides new insights into fungal pathogenesis and for developing alternative biocontrol of pathogenic nematodes by nematophagous fungi. IMPORTANCE Nematodes are among the most abundant animals on our planet. Many of them are parasites in animals and plants and cause human and animal health problems as well as agricultural losses. Studying the interaction of nematodes and their microbial pathogens is of great importance for the biocontrol of animal and plant parasitic nematodes. In this study, we found that the model nematode Caenorhabditis elegans can recognize its fungal pathogen, the nematophagous fungus Purpureocillium lavendulum, through fungal-produced ethanol. Then the nematode elevated the reactive oxygen species production in the gut to inhibit fungal growth in an ethanol dehydrogenase-dependent manner. With this mechanism, novel biocontrol strategies may be developed targeting the ethanol receptor or metabolic pathway of nematodes. Meanwhile, as a volatile organic compound, ethanol should be taken seriously as a vector molecule in the microbial-host interaction in nature.

Efficacy of Duddingtonia flagrans (Bioverm®) on the biological control of buffalo gastrointestinal nematodes.

We evaluated the efficacy of Bioverm®, a commercial product containing Duddingtonia flagrans, on the control of buffalo (Bubalus bubalis) gastrointestinal nematodes. We randomly divided 12 buffaloes into two groups of six animals. In the treated group, each animal received a Bioverm®`s single dose of 1g (105 chlamydospores of D. flagrans) to 10 kg of live weight; in the control group, each animal received 1g of corn bran for each 10 kg of live weight as a placebo. Fecal samples were individually collected from 12, 24, 36, 48, 60 and 72 h after treatments. To examine 1) viability of chlamydospores passed through the gastrointestinal tract, 2 g of faeces and 1000 infective larvae (L3) were added to Petri dishes with 2% water-agar, and 2) to examine larval predation by D. flagrans during fecal cultures, 2000 L3 were added. In the Petri dishes, were observed significant reductions (p < 0.01) in the treated group after 48 (56.7%) and 60 h (91.5%). In the fecal cultures, significant reductions (p < 0.01) occurred in the treated group from 36 h (75%), with larval reduction up to 72 h. High larval predation rate occurred 60 h after Bioverm® administration. Bioverm® maintained viability and predation capacity after passage through the buffalo's gastrointestinal tract, showing efficacy on gastrointestinal nematodes.

On the interactions involving serine proteases obtained from Monacrosporium thaumasium (Ascomycota: Orbiliomycetes) and deoxyribonucleic acid (DNA): biological macromolecules in action.

The use of force spectroscopy approaches performed with optical tweezers can be very useful in determining the binding modes and the physical chemistry of DNA interactions with ligands, from small drugs to proteins. Helminthophagous fungi, on the other hand, have important enzyme secretion mechanisms for various purposes, and the interactions between such enzymes and nucleic acids are very poorly studied. Therefore, the main goal of the present work was to investigate, at the molecular level, the mechanisms of interaction between fungal serine proteases and the double-stranded (ds) DNA molecule. Experimental assays performed with this single molecule technique consist in exposing different concentrations of the protease of this fungus to dsDNA until saturation while monitoring the changes on the mechanical properties of the macromolecular complexes formed, from where the physical chemistry of the interaction can be deduced. It was found that the protease binds strongly to the double-helix, forming aggregates and changing the persistence length of the DNA molecule. The present work thus allowed us to infer information at the molecular level on the pathogenicity of these proteins, an important class of biological macromolecules, when applied to a target specimen.

Trapping Behaviour of Duddingtonia flagrans against Gastrointestinal Nematodes of Cattle under Year-Round Grazing Conditions.

The purpose of using nematophagous fungi as biological control agents of gastrointestinal nematodes of livestock is to reduce the build-up of infective larvae on pasture and thus avoid clinical and subclinical disease. As the interaction of fungus-larval stages takes place in the environment, it is crucial to know how useful the fungal agents are throughout the seasons in areas where livestock graze all year-round. This study was designed to determine the predatory ability of the nematophagous fungus Duddingtonia flagrans against gastrointestinal nematodes of cattle during four experiments set up in different seasons. In each experiment, faeces containing eggs of gastrointestinal nematodes were mixed with 11,000 chlamydospores/g and deposited on pasture plots. A comparison between fungal-added faeces and control faeces without fungus were made with regard to pasture infectivity, larval presence in faecal pats, faecal cultures, faecal pat weight, and temperature inside the faecal mass. In three of the four experiments, Duddingtonia flagrans significantly reduced the population of infective larvae in cultures (68 to 97%), on herbage (80 to 100%), and inside the faecal pats (70 to 95%). The study demonstrated the possibility of counting on a biological control tool throughout most of the year in cattle regions with extensive grazing seasons.

The Growth and Conidiation of Purpureocillium lavendulum Are Co-Regulated by Nitrogen Sources and Histone H3K14 Acetylation.

Plant-parasitic nematodes cause severe economic losses to agriculture. As important biocontrol agents, nematophagous fungi evolved the ability to obtain nitrogen sources from nematodes. However, the impact of nitrogen sources on the growth and development of these fungi is largely unknown. In this study, we aimed to better understand how nitrogen sources could influence vegetative growth and conidiation through epigenetic regulation in the nematophagous fungus, Purpureocillium lavendulum. Through nutrition screening, we found a phenomenon of the fungus, limited colony extension with a large amount of conidia production when cultured on PDA media, can be altered by adding ammonia nitrate. Characterized by site-directed mutagenesis, the histone H3K14 acetylation was found to be involved in the alternation. Furthermore, the acetyltransferase PlGCN5 was responsible for H3K14 acetylation. Knockout of Plgcn5 severely diminished conidiation in P. lavendulum. Chip-seq showed that H3K14ac distributed in conidiation regulating genes, and genes in the MAPK pathway which may be the downstream targets in the regulation. These findings suggest that histone modification and nitrogen sources coordinated lifestyle regulation in P. lavendulum, providing new insight into the mechanism of growth regulation by nutritional signals for the carnivorous fungus.

Polydomus karssenii gen. nov. sp. nov. is a dark septate endophyte with a bifunctional lifestyle parasitising eggs of plant parasitic cyst nematodes (Heterodera spp.).

In this study fungal strains were investigated, which had been isolated from eggs of the cereal cyst nematode Heterodera filipjevi, and roots of Microthlaspi perfoliatum (Brassicaceae). The morphology, the interaction with nematodes and plants and the phylogenetic relationships of these strains originating from a broad geographic range covering Western Europe to Asia Minor were studied. Phylogenetic analyses using five genomic loci including ITSrDNA, LSUrDNA, SSUrDNA, rpb2 and tef1-α were carried out. The strains were found to represent a distinct phylogenetic lineage most closely related to Equiseticola and Ophiosphaerella, and Polydomus karssenii (Phaeosphaeriaceae, Pleosporales) is introduced here as a new species representing a monotypic genus. The pathogenicity tests against nematode eggs fulfilled Koch's postulates using in vitro nematode bioassays and showed that the fungus could parasitise its original nematode host H. filipjevi as well as the sugar beet cyst nematode H. schachtii, and colonise cysts and eggs of its hosts by forming highly melanised moniliform hyphae. Light microscopic observations on fungus-root interactions in an axenic system revealed the capacity of the same fungal strain to colonise the roots of wheat and produce melanised hyphae and microsclerotia-like structure typical for dark septate endophytes. Confocal laser scanning microscopy further demonstrated that the fungus colonised the root cells by predominant intercellular growth of hyphae, and frequent formation of appressorium-like as well as penetration peg-like structures through internal cell walls surrounded by callosic papilla-like structures. Different strains of the new fungus produced a nearly identical set of secondary metabolites with various biological activities including nematicidal effects irrespective of their origin from plants or nematodes.

Molecular Defense Response of Bursaphelenchus xylophilus to the Nematophagous Fungus Arthrobotrys robusta.

Bursaphelenchus xylophilus causes pine wilt disease, which poses a serious threat to forestry ecology around the world. Microorganisms are environmentally friendly alternatives to the use of chemical nematicides to control B. xylophilus in a sustainable way. In this study, we isolated a nematophagous fungus-Arthrobotrys robusta-from the xylem of diseased Pinus massoniana. The nematophagous activity of A. robusta against the PWNs was observed after just 6 h. We found that B. xylophilus entered the trap of A. robusta at 24 h, and the nervous system and immunological response of B. xylophilus were stimulated by metabolites that A. robusta produced. At 30 h of exposure to A. robusta, B. xylophilus exhibited significant constriction, and we were able to identify xenobiotics. Bursaphelenchus xylophilus activated xenobiotic metabolism, which expelled the xenobiotics from their bodies, by providing energy through lipid metabolism. When PWNs were exposed to A. robusta for 36 h, lysosomal and autophagy-related genes were activated, and the bodies of the nematodes underwent disintegration. Moreover, a gene co-expression pattern network was constructed by WGCNA and Cytoscape. The gene co-expression pattern network suggested that metabolic processes, developmental processes, detoxification, biological regulation, and signaling were influential when the B. xylophilus specimens were exposed to A. robusta. Additionally, bZIP transcription factors, ankyrin, ATPases, innexin, major facilitator, and cytochrome P450 played critical roles in the network. This study proposes a model in which mobility improved whenever B. xylophilus entered the traps of A. robusta. The model will provide a solid foundation with which to understand the molecular and evolutionary mechanisms underlying interactions between nematodes and nematophagous fungi. Taken together, these findings contribute in several ways to our understanding of B. xylophilus exposed to microorganisms and provide a basis for establishing an environmentally friendly prevention and control strategy.

Nematophagous Fungi: A Review of Their Phosphorus Solubilization Potential.

Nematophagous fungi (NF) are a group of diverse fungal genera that benefit plants. The aim of this review is to increase comprehension about the importance of nematophagous fungi and their role in phosphorus solubilization to favor its uptake in agricultural ecosystems. They use different mechanisms, such as acidification in the medium, organic acids production, and the secretion of enzymes and metabolites that promote the bioavailability of phosphorus for plants. This study summarizes the processes of solubilization, in addition to the mechanisms of action and use of NF on crops, evidencing the need to include innovative alternatives for the implementation of microbial resources in management plans. In addition, it provides information to help understand the effect of NF to make phosphorus available for plants, showing how these biological means promote phosphorus uptake, thus improving productivity and yield.

Two strains Neocosmosporastercicola (Sordariomycetes, Nectriaceae) with high nematicidal activity, isolated from the cysts of Globodera sp. (Heteroderidae) in China.

Plant-parasitic nematodes (PPNs) are significant pests that result in considerable economic losses in global crop production. Due to the high toxicity of chemical nematicides, there is a need to develop new strategies for nematode control. In this context, nematophagous fungi may offer a viable option for biological control. Two fungal strains (GUCC2212 and GUCC2232) were isolated from cysts of Globodera sp., identified as Neocosmosporastercicola. The fungal filtrates of the strains were evaluated for their nematicidal activity against three species of PPNs: Aphelenchoidesbesseyi, Bursaphelenchusxylophilus and Ditylenchusdestructor. The fermentation filtrates of two strains exhibited substantial toxicity towards the evaluated nematodes, with mortality rates reaching up to 100% within 72 h. Concurrently, N.stercicola also demonstrated predatory and parasitic behavior. The eggs of Globodera sp. were parasitized by the two strains. N.stercicola represents a newly recorded species in China and a novel nematophagous species. In conclusion, the two strains of N.stercicola show promise as biocontrol agents for PPNs management.