Search Results (962)

The management of Meloidogyne incognita often depends on chemical nematicides, which pose environmental and health risks. This study investigated the potential of bacterial strains isolated from uncultivated native soil as biocontrol agents and plant growth-promoting rhizobacteria (PGPR) in tomato plants artificially infected with this nematode. Fifteen strains were screened in vitro for nematicidal and ovicidal activity, and four promising strains (307, GB16, GB24, and GB29) were selected for greenhouse trials. All strains reduced the nematode reproduction factor and the number of nematodes/g of root. Strains 307 and GB24 showed the highest reductions, 61.39 and 57.24%, respectively. Despite some positive physiological trends, Bacillus spp. did not promote a significant increase in plant growth. Metabolomic analysis revealed that the strains produced a wide range of primary metabolites with potential nematicidal activity. All strains also secreted proteases and chitinases, enzymes linked to nematode cuticle degradation. Preliminary identification based on the 16S rRNA gene and phylogenetic analysis grouped the four strains into the Bacillus subtilis group (strains GB16, GB29 and 307) or Bacillus cereus group (strain GB24); however, genome sequencing will be required in future studies. Overall, strains 307 and GB24 demonstrated strong biocontrol potential, supporting their use as sustainable and complementary alternatives to chemical nematicides. Full article

The cereal cyst nematode, Heterodera avena, is responsible for substantial economic losses in the global production of wheat, barley, and other cereal crops. Extracellular enzymes, particularly those from the glycoside hydrolase 18 (GH18) family, such as chitinases secreted by Trichoderma spp., play a crucial role in nematode control. However, the genome-wide analysis of Trichoderma longibrachiatum T6 (T6) GH18 family genes in controlling of H. avenae remains unexplored. Through phylogenetic analysis and bioinformatics tools, we identified and conducted a detailed analysis of 18 GH18 genes distributed across 13 chromosomes. The analysis encompassed gene structure, evolutionary development, protein characteristics, and gene expression profiles following T6 parasitism on H. avenae, as determined by RT-qPCR. Our results indicate that 18 GH18 members in T6 were clustered into three major groups (A, B, and C), which comprise seven subgroups. Each subgroup exhibits highly conserved catalytic domains, motifs, and gene structures, while the cis-acting elements demonstrate extensive responsiveness to hormones, stress-related signals, and light. These members are significantly enriched in the chitin catabolic process, extracellular region, and chitinase activity (GO functional enrichment), and they are involved in amino sugar and nucleotide sugar metabolism (KEGG pathway enrichment). Additionally, 13 members formed an interaction network, enhancing chitin degradation efficiency through synergistic effects. Interestingly, 18 members of the GH18 family genes were expressed after T6 parasitism on H. avenae cysts. Notably, GH18-3 (Group B) and GH18-16 (Group A) were significantly upregulated, with average increases of 3.21-fold and 3.10-fold, respectively, from 12 to 96 h after parasitism while compared to the control group. Meanwhile, we found that the GH18-3 and GH18-16 proteins exhibit the highest homology with key enzymes responsible for antifungal activity in T. harzianum, demonstrating dual biocontrol potential in both antifungal activity and nematode control. Overall, these results indicate that the GH18 family has undergone functional diversification during evolution, with each member assuming specific biological roles in T6 effect on nematodes. This study provides a theoretical foundation for identifying novel nematicidal genes from T6 and cultivating highly efficient biocontrol strains through transgenic engineering, which holds significant practical implications for advancing the biocontrol of plant-parasitic nematodes (PPNs). Full article

Ilicic acid, nerolidol, and 9-hydroxynerolidol are major components of the aerial parts of Dittrichia viscosa. These components were selectively isolated in multigram quantities and used as lead compounds to generate diversity in the search for new natural-product-derived pesticides. A total of 29 derivatives of these three molecules—some of which are known natural products—were generated by subjecting these natural products to different transformations. In order to explore potential applications in sustainable biocontrol, some of the compounds generated were evaluated for plant protection potential against insect pests (Spodoptera littoralis, Myzus persicae, Rhopalosiphum padi), against the nematode Meloidogyne javanica, and for their phytotoxic effects on ryegrass (Lolium perenne) and lettuce (Lactuca sativa). Additionally, their effects against the tick Hyalomma lusitanicum have been tested. Compound 11 was found to be antifeedant against S. littoralis and nematicidal. Compounds 3a and 8 were potent antifeedants against R. padi. None of the tested compounds significantly inhibited lettuce growth, and compounds 17, 3, and 3a even promoted root development. Conversely, compounds 3, 4, 11, 17, and 21a exhibited strong herbicidal activity on ryegrass. In larvicidal assays against H. lusitanicum, compounds 3, 3a, 11, 17, 29, and 33 were active, with compound 29 being six times more active than the positive control nootkatone. Full article

This study investigated the distribution of pine wood nematodes (PWNs, Bursaphelenchus xylophilus) and their co-occurrence with B. mucronatus in recently dead pine trees across coastal and inland regions while monitoring the seasonal emergence patterns of Monochamus alternatus from 2021 to 2023. Nematodes were extracted from felled trees and beetle bodies using the Baermann funnel method. Aggregation pheromone traps were used to monitor vector activity and to assess temperature-dependent emergence. The results showed a negative correlation between PWN and B. mucronatus density (r = −0.73, p < 0.01), which prompted tests on interspecific interactions. M. alternatus emergence was positively associated with average temperature (r = 0.74–0.78), supporting the temperature-informed surveillance timing in this dataset. These findings highlight the role of climate-driven dynamics in shaping vector behavior and nematode population structures. This study supports the development of sustainable temperature-responsive management strategies for controlling pine wilt disease. These strategies provide a foundation for climate-resilient forest health and long-term ecosystem sustainability. Full article

The present study examined the presence of concomitant intestinal parasites and bacteria in individuals infected with Enterobius vermicularis in Bulgaria, and analyzed its effects on the intestinal microbiome and the risk of co-infection. Fecal samples from people with and without (control group) enterobiasis were tested for the presence of concomitant bacterial infection. The results were compared to find out about the intestinal microbiome in these groups. The microbiological examination of the control group showed that 8.3% had only conditionally pathogenic flora. However, in individuals with enterobiasis, 56% had normal intestinal bacterial flora, but 46% had disturbed microbiota: 7% were carriers of pathogenic intestinal bacteria and 24% had opportunistic pathogens. The most prevalent were Klebsiella pneumoniae (49%), followed by Enterobacter spp. (22%), and Proteus mirabilis (12.2%). Our study is the first in the country to investigate the impact of E. vermicularis infection on the composition and quality of the gut microbiome, as well as the potential for co-infections with pathogenic gut bacteria. Although our findings are preliminary, they suggest that this nematode may significantly contribute to a predisposition for dysbiosis or the onset of secondary bacterial infections. Full article

Gastro-intestinal nematodes (GINs) are still of great concern in grazing ruminants, such as camelids, ovines and caprines, affecting animal health and productivity. This is mainly due to the development of anthelmintic resistance (AR) to the compounds used long term, without much evaluation on their efficacy, including ivermectin (IVM), the most used anthelmintic drug in livestock. The aims of this study were to determine the efficacy of IVM and identify which GIN species are affecting different ruminant farms in Quebec (QC), Canada. Firstly, we collected fecal samples from six farms with different ruminant species (camelids, goats and sheep) before and after IVM treatment when applicable, analyzing them by Fecal Egg Count (FEC) and further assessments on IVM efficacy through the Fecal Egg Count Reduction Test (FECRT). In addition, molecular analyses were conducted using PCR, targeting the ITS-2 and COX-1 genes to identify GIN species. FECRT was applied only for three farms, showing that variable results with optimal efficacy (ranging from 95.5–100%) were obtained in only one farm, whereas on the other two farms, FECRT exhibited reduced efficacy, suggesting the development of IVM resistance. Among the GIN species found, Haemonchus contortus and Trichostrongylus vitrinus were identified in most of the farms, being present in sheep, goat, llama and alpaca farms, whereas Teladorsagia circumcincta was identified only in sheep and llama samples from four farms but not in alpaca samples. Trichostrongylus axei and Chabertia ovina were present in two farms (sheep and sheep and llamas). Oesophagostomum venulosum was detected in one sheep and one alpaca farm. Only one sheep farm was positive for Trichostrongylus colubriformis and Cooperia curticei. Also, Nematodirus spp. and Trichuris spp. were found in four farms, including sheep and camelids. In addition, three other species were found in camelids, including Camelostrongylus mentulatus (only in the llama samples), whereas Lamanema chavezi and Marshallagia marshalli were identified in one alpaca farm. Therefore, our work reports evidence of an uneven efficacy of IVM against GINs from ruminant farms, including the most likely emergence of IVM resistance. The diversity of GIN species found in ruminant farms in QC along with the inconsistent IVM efficacy are helpful information for veterinarians and animal producers in setting an optimal parasite management programs, including the proper use of IVM and alternative anthelmintic drugs to control these pathogens in grazing livestock. Full article

Background/Objectives: Gastrointestinal nematode infections represent a major constraint to sheep production globally, with widespread drug resistance requiring alternative control strategies. Methods: This systematic review combined genome-wide association study findings to understand the genetic basis underlying parasite resistance traits in sheep. Following PRISMA guidelines, we identified 22 studies including 28,033 samples from 32 breeds across 11 countries, extracting 1580 candidate genes associated with resistance traits, including fecal egg count, packed cell volume, and immunoglobulin levels. Gene prioritization analysis using ToppGene identified 75 high-confidence candidate genes. Results: Functional enrichment analysis revealed significant involvement of the JAK-STAT signaling pathway, inflammatory response processes, and immune-related biological functions. Protein–protein interaction network analysis identified nine key hub genes: TNF, STAT3, STAT5A, PDGFB, ADRB2, MAPT, ITGB3, SMO, and GH1. The JAK-STAT pathway emerged as particularly important, with multiple core genes involved in cytokine signaling and immune cell development. These findings demonstrate that parasite resistance involves complex interactions between inflammatory responses, immune signaling networks, and metabolic processes. Conclusions: This comprehensive genetic framework provides essential insights for developing genomic selection strategies and marker-assisted breeding programs to enhance natural parasite resistance in sheep, offering a sustainable approach to reducing drug dependence and improving animal welfare in global sheep production systems. Full article

Photorhabdus and Xenorhabdus bacteria, members of the Morganellaceae family, are sources of novel natural products for the biocontrol of fungal pathogens in soybean production. This study demonstrated the inhibitory effects of metabolites from four Photorhabdus and Xenorhabdus strains (including a local isolate, X. szentirmaii PAM 25), against four key phytopathogenic fungi. Bacterial metabolite efficacy and fungal susceptibility varied. Xenorhabdus szentirmaii DSM 16338, X. szentirmaii PAM 25, and X. doucetiae demonstrated significant inhibition (>90%) against Sclerotinia sclerotiorum, Botrytis cinerea, and Macrophomina phaseolina, exhibiting superior efficacy compared to X. nematophila and Photorhabdus kayaii. Fusarium oxysporum demonstrated greater resistance to the bacterial supernatants. We identified fabclavine, pyrollizixenamide, and szentirazine from X. szentirmaii, and xenocoumacins from X. doucetiae as the antifungal bioactive compounds in the respective easyPACid mutants. Furthermore, we assessed the efficacy of X. szentirmaii PAM 25 and its metabolites in protecting soybean seeds from S. sclerotiorum and investigated the shelf stability of the bacterial metabolites as the fungus suppressors. Cell-free supernatant maintained >80% inhibition of S. sclerotiorum after one year at 5–35 °C. Importantly, the cell-free supernatant, as well as the bacterial culture, effectively inhibited S. sclerotiorum in seed treatments, ensuring ≥80% seed germination, comparable to thiophanate-methyl + fluazinam fungicide. This study demonstrates that the direct seed application of Xenorhabdus and Photorhabdus bacteria offers a practical and innovative biological control method against soil-borne fungal pathogens. Full article

Entomopathogenic nematodes (EPNs) are valuable biological control agents and research models in agriculture and ecology. Traditional extraction and rearing methods for EPNs, such as the Baermann funnel and White trap, work well but have limitations in efficiency and practicality. The NEMA Device, constructed from PVC components, was designed to address these limitations by combining extraction and rearing into a single tool with improved portability, scalability, and ease of use. The efficiency of the NEMA Device was evaluated by comparing it to the conventional Baermann funnel extraction method and the White trap method for nematode multiplication. Validation of the instrument was performed using two nematode species, Steinernema khuongi and Heterorhabditis bacteriophora, which vary in size and can be used for pest control. Our results demonstrated that the NEMA Device achieved higher recovery rates of both S. khuongi and H. bacteriophora compared to the Baermann method. Additionally, the production rate of nematodes using the NEMA Device was comparable to that of the White trap method, with no significant difference observed between the two methods. The NEMA Device offers a standardized, cost-effective methodology for the extraction and multiplication of EPNs, enhancing the accessibility and efficiency of studying these agriculturally important nematodes and potentially improving biological control outcomes. Full article

Pine wilt disease, which is induced by pine wood nematode (PWN, Bursaphelenchus xylophilus), has caused huge economic and ecological losses. To overcome the drawbacks of chemical control against PWN, twenty compounds were screened, and a synergistic botanical–chemical combination was identified. A proportion of abamectin to rotenone of 7:3 (5.73 and 1.78 mg/L, respectively) achieved the highest co-toxicity coefficient of 231.09 with a median lethal concentration of 3.18 mg/L. It revealed 0% mortality in Pinus massoniana seedlings at 60 days post-treatment when applied at 400 times the synergistic concentration (2.29 g/L abamectin + 0.71 g/L rotenone) at 7 days after PWN inoculation. Furthermore, the synergistic combination significantly affected the physiological activity and population dynamics of PWN. Female oviposition was reduced by 71.92%, the egg hatching rates declined to 13.09 ± 0.02%, and head thrashing frequency was inhibited by 99.23 ± 0.01%. The enzymatic activities of peroxidase, acetylcholinesterase, succinate dehydrogenase, and glutathione S-transferase were significantly increased, while the population size declined by 96.17%. Transcriptomic and gene expression analyses suggested a potential “Na⁺/Ca²⁺/Cl⁻ ionic storm,” since the synergistic combination significantly activated genes associated with voltage-gated calcium channels, glutamate-gated chloride channels, and amiloride-sensitive sodium channels. These findings provide an eco-friendly strategy for PWN management via chemical control. Full article

Plant parasitic nematodes are a significant agricultural threat, causing substantial economic losses. Methyl bromide, a commonly used nematicide, has been banned due to its harmful environmental and human health effects. As an alternative, the expression of the programmed cell death (PCD) gene CED4 from Caenorhabditis elegans in transgenic plants has been proposed to control nematode populations. In this study, the interaction between CED4 and other proteins was analyzed, and peptide sequences representing interaction domains were identified. Efficacy assays demonstrated that specific peptides—particularly Peptides 2 and 3 (N-terminal α/β domain) and Peptide 12 (C-terminal HD-2 domain)—induced significant mortality in C. elegans, while other peptides were ineffective. The study further investigated whether these peptides, along with modified CED4-like peptides (2a, 3a, and 12a), induce PCD in C. elegans via the activation of the nematode’s endogenous PCD pathway. Testing was conducted on wild-type and mutant strains of C. elegans (ced-4 and ced-3 mutants). Nematode survival was monitored over 34 days, revealing that c3 mutants survived exposure to CED4-like peptides, suggesting that the peptides trigger PCD through the activation of the endogenous cell death pathway. These findings support the potential use of CED4-based peptides as a novel strategy for nematode control. Full article

Grapevine viruses reduce harvests and degrade fruit quality, but their genetic diversity in Kazakhstan has remained unexplored. We collected symptomatic leaves from local vineyards and recovered eleven fragments of the coat-protein gene: one from grapevine fanleaf virus, five from grapevine virus A, and five from grapevine leafroll-associated virus 3. After Sanger sequencing, we compared these fragments with more than one thousand international counterparts to place the Kazakh strains on the global family tree. The results reveal a clear spectrum of genetic diversity that mirrors each virus’s route of spread. Grapevine virus A, which is moved both mechanically and by insects, proved the most variable; grapevine fanleaf virus, carried by dagger nematodes and pruning sap, had intermediate variability; and grapevine leafroll-associated virus 3, moved only by mealybugs and scales, was highly conserved. All Kazakh sequences fell inside established foreign lineages, showing that the viruses were imported multiple times rather than evolving locally. Grapevine virus A will require broad-coverage or multiplex PCR primers to avoid false negatives, whereas the stable leafroll virus can be monitored with a single high-sensitivity assay. Combined with vector management—mealybug control for leafroll, and nematode testing for fanleaf—these data lay the groundwork for a national clean-plant program and more resilient vineyards across Central Asia. Full article

Slug-parasitic nematodes are promising biological control agents against gastropod pests, yet their responses to cereal root volatiles remain poorly understood. We evaluated the chemotactic behavior of Phasmarhabditis papillosa, Oscheius myriophilus, and Oscheius onirici toward synthetic standards of four barley root-derived VOCs—dimethyl sulfide (DMS), hexanal (H), 2-pentylfuran (2PF), and (E)-non-2-enal (N2E)—and their synthetic blends at two temperatures (18 °C and 22 °C). Significant species-specific and temperature-dependent differences were observed. 2PF and DMS consistently elicited the strongest attraction, particularly for O. myriophilus and P. papillosa, while aldehydes produced weaker or reduced-attraction responses. VOC blends often showed masking or antagonistic effects, suggesting complex signal integration. Temperature enhanced overall chemotactic activity, indicating its importance in modulating sensory behavior. These findings provide new insights into the chemical ecology of slug-parasitic nematodes and support the development of semiochemical-based biocontrol strategies tailored to species and environmental conditions. Full article

Heterodera schachtii, a nematode primarily feeding on sugar beet and cruciferous plants, e.g., rapeseed, cabbage, broccoli, mustard, and radish, had a significant impact on Camelina sativa (L.) Crantz. The isolation of H. schachtii cysts from C. sativa roots and a known data gap regarding their development on this plant prompted an investigation into their interaction. A pot experiment conducted under controlled conditions in a growth chamber showed that H. schachtii completes its full development cycle in the roots of spring (UP, Smielowska, Borowska, Omega) and winter (Lemka, Maczuga, Luna, Przybrodzka) camelina cultivars at temperatures of 15, 20, and 25 °C. Female nematodes and cysts were most abundant in the Omega cultivar at 20 °C, averaging 9.25 per plant. Nematode feeding did not affect the height or fresh weight of the plants. Plants of the Przybrodzka cultivar had fewer leaves than the control plants. More siliques were observed on the control plants of the UP cultivar kept at 15 °C and those of the UP and Borowska cultivars at 20 °C. Under natural conditions, the number of eggs and larvae in the soil decreased by approximately 50% during the camelina growth cycle for both spring and winter biotypes. Full article

Insect-derived frass is gaining attention as a circular bioeconomy product with fertilizing and pest-suppressive potential. This study investigates Tenebrio molitor frass as a soil amendment for promoting beneficial nematodes and suppressing Meloidogyne incognita. A 40-day pot experiment on clay loam soil tested with six inputs: raw and heat-treated frass (0.5%, 1% w/w), Melia azedarach fruit powder (1.6%), and an untreated control. Soil nematode communities were assessed at 5 and 40 days after application (DAA), and nematicidal activity was evaluated in vitro. Raw frass at 1% induced a rapid response from free-living nematodes at 5 DAA, with increased abundance of bacterivorous taxa such as Rhabditis and Acrobeloides, alongside a higher Enrichment Index (EI), indicating short-term nutrient availability. At 40 DAA, only 1% raw frass consistently supported more cp-1 bacterivores and slightly increased Shannon diversity. Network analysis revealed more connected, modular structures in raw frass treatments, suggesting enhanced food web complexity. However, omnivore and predator effects were limited. Raw frass extracts caused over 80% paralysis of Meloidogyne incognita juveniles within 24 h, significantly outperforming heat-treated frass and Melia extracts. T. molitor frass moderately stimulates opportunistic nematodes and provides strong nematicidal effects, supporting its potential as a multifunctional input for sustainable soil management. Full article