Search Results (71)

Trichostrongylid nematodes are globally distributed gastrointestinal parasites of major veterinary and, in some cases, zoonotic importance. Accurate identification often requires an integrative approach because morphology alone may be compromised by specimen damage, cryptic diversity, and dimorphic species complexes. In the Philippines previous work has been largely limited to coproscopy, with no published DNA-based studies on adult trichostrongylids or scanning electron microscopy (SEM) documentation. Here, we provide an integrative characterization of Haemonchus contortus and Trichostrongylus axei recovered from a single goat in Mindanao, Philippines, in 2023. Identification was based on light microscopy, SEM, morphometry, and sequence data from the cox1 and ITS regions. Phylogenetic analyses and a haplotype network for H. contortus placed the Philippine material within a widely distributed lineage complex with weak geographic structuring. Because the study is based on parasites from a single host, the findings should be interpreted as a taxonomic and faunistic record rather than evidence for broader epidemiological or population-level patterns. This study provides the first molecular record of trichostrongylid nematodes from the Philippines and the first SEM-based documentation of H. contortus in the country. Broader sampling is needed to assess parasite diversity, distribution, genetic variation, and potential veterinary and public health relevance nationwide. Full article

Root-knot nematodes (RKNs; Meloidogyne spp.) are among the most destructive plant parasites, causing severe yield losses in diverse crops. Reactive oxygen species (ROS), particularly superoxide radicals (O₂•⁻) and hydrogen peroxide (H₂O₂), are central regulators of plant–RKN interactions. This review synthesizes current molecular, biochemical, genetic, transcriptomic, and translational evidence showing that the outcome of infection is determined by the spatiotemporal regulation of H₂O₂ rather than by ROS abundance alone. In resistant interactions, nematode perception activates PTI-associated signaling through selected cell-surface receptor complexes, including some BAK1/SERK3-associated pathways, together with BIK1, Ca²⁺ signaling, and RBOHD/F, generating a sustained oxidative activity associated with salicylic acid-dependent immune signaling and reduced H₂O₂-scavenging capacity and coupled to hypersensitive response, lignin and callose deposition, and feeding site restriction. In susceptible interactions, RKNs deploy ROS-targeting effectors such as Mi-CRT, MjTTL5, CATLe, Mj-NEROSs, and CMII to suppress ROS production, enhance antioxidant scavenging, or weaken SA-dependent defense. Evidence from a cyst-nematode system suggests that RBOH-derived ROS can restrict excessive cell death around syncytia; whether an analogous lower-redox requirement exists in RKN-induced giant cells remains unresolved. Finally, redox-based strategies, including CRISPR/Cas editing, host-induced gene silencing, chemical priming, and biocontrol, are discussed as promising approaches for durable and sustainable nematode resistance. Full article

The pinewood nematode (PWN, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle)), first introduced into China in 1982, has since spread rapidly, posing a serious threat to forest resource security and ecological balance. This study aimed to analyze the genetic diversity and genetic structure of PWN in eight geographic populations (60 individuals) of Guizhou Province using single nucleotide polymorphisms (SNPs). Results revealed low genetic diversity (Ho values varied from 0.123 to 0.229; He values ranged between 0.117 and 0.212) across the eight sampled populations, along with low levels of genetic differentiation (pairwise Fst values varied from 0.005 to 0.183) among them. Gene flow was generally high between populations, and no clear geographical clustering was observed based on ADMIXTURE, PCA and phylogenetic analysis. These findings provided a scientific basis for tracking the dispersal and identifying the origins of PWN infestations in China. Full article

Helminth infections remain a major constraint to livestock productivity, particularly in regions where domestic animals and wildlife share grazing habitats. This study investigated the molecular diversity and transmission dynamics of helminth communities in sheep (Ovis aries) and saiga antelope (Saiga tatarica) in West Kazakhstan. A total of 35 animals (20 sheep and 15 saiga) were examined, and helminths were identified using polymerase chain reaction targeting the ITS1 region of ribosomal DNA for nematodes and the mitochondrial cox1 gene for cestodes. Of the 20 analyzed samples, 80% were successfully identified at the molecular level. Detected species included Haemonchus contortus, Trichuris ovis, Chabertia ovina, Moniezia expansa, and Avitellina centripunctata. Phylogenetic analysis revealed that Chabertia ovina isolates from both hosts clustered within a single monophyletic clade, indicating high genetic similarity and supporting potential cross-species transmission. Mitochondrial markers provided higher resolution for cestode differentiation, whereas ITS1 was effective for nematode identification. The predominance of Chabertia ovina in saiga suggests ecological adaptation and efficient transmission within wild populations. These findings highlight the epidemiological significance of shared grazing ecosystems and underscore the need for integrated parasite control strategies that consider both livestock and wildlife reservoirs. Full article

Background: Pine wilt disease (PWD), caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus), is a devastating forest disease. It has been reported in five provincial-level regions in Southwest China (Chongqing, Guizhou, Sichuan, Yunnan, and Tibet), threatening local pine forest ecosystems. Methods: To unravel the population genetic variation and population differentiation of PWN isolates in this region, we purified eighty-one isolates for whole-genome resequencing and bioinformatics analysis, identifying candidate genes associated with runs of homozygosity (ROH). Results: Population structure analysis clustered the 81 isolates into three distinct genetic groups (Groups 1, 2, and 3). Notably, Group 1 exhibited fewer and shorter ROH segments compared to Groups 2 and 3, indicating higher genetic diversity and a different inbreeding history. Functional annotation of genes overlapping ROH regions revealed that Group 1 contained a subset of the genes identified in Groups 2 and 3, primarily enriched in specific molecular function categories. Conclusions: The PWN populations in Southwest China exhibit genetic differentiation, forming three distinct groups. Group 1 shows a reduced ROH burden and lower inbreeding levels, whereas Groups 2 and 3 display more extensive ROH patterns that may reflect historical demographic processes or potential adaptive selection. The differential distribution of ROH-associated genes across groups suggests possible variation in historical demographic processes and could suggest possible directional selection. These findings contribute to understanding the population history and genomic characteristics of PWN in Southwest China, providing insights that could support disease management strategies. Full article

Pine wilt disease (PWD), caused by Bursaphelenchus xylophilus, is a destructive forest disease leading to rapid mortality. Although Chongqing is a major epidemic region in China, the population genetic structure of B. xylophilus and the ecological interactions among nematode occurrence, blue stain formation, and microbial community dynamics remain insufficiently clear. This study systematically surveyed nematode incidence and performed morphological and molecular identification, revealing strong correlations between nematode presence, blue stain, and insect infestation (p < 0.0001). Within Monochamus alternatus, nematodes were mainly distributed in the abdomen and thorax (p < 0.0001). High-throughput sequencing showed significantly higher fungal (e.g., Leptographium) and bacterial (e.g., Burkholderia-Caballeronia-Paraburkholderia) diversity in diseased than healthy pinewood, indicating pronounced microbial shifts during disease progression. mtCOI-based genetic analyses of 162 nematodes from 11 populations revealed five haplotypes, with Hap1 shared across all populations. AMOVA indicated that over 80% of genetic variation occurred within populations, and neutrality and mismatch analyses suggested recent expansion in some populations (Beibei, Jiangbei, Rongchang). These findings clarify nematode epidemiology, microbial shifts, and genetic characteristics in Chongqing, providing a scientific basis for precise sampling, rapid detection, and integrated management of PWD, and suggest that microbial community changes may contribute to rapid pine decline. Full article

Intestinal bacteria play crucial roles in maintaining host health and regulating disease. While much of the current research has focused on how changes in the gut microbiota affect various physiological functions of the host, little is known about how the host’s genetic factors shape gut microbiota diversity or how gut-dominant bacteria influence host innate immunity and lifespan. In this study, we demonstrated that a mutation in the Caenorhabditis elegans ERK-encoding gene, mpk-1, promotes the enrichment of Raoultella planticola in the gut of worms, and the bacterium confers resistance to infection by the pathogenic bacterium Pseudomonas aeruginosa PA14 (PA14) in worms. Mechanistically, a compromised immune response, which is dependent on the let-60–mpk-1 pathway, promotes the colonization of R. planticola in mpk-1 mutants. Importantly, R. planticola induces autophagy, thereby enhancing nematode resistance to PA14 infection and extending its lifespan. Our findings shed light on how immune-compromised mpk-1 mutants increase colonization permissiveness and utilize R. planticola to bolster their antibacterial immunity against pathogenic P. aeruginosa, offering new insights into the regulatory mechanisms of host–microbiota interactions. These results emphasize the complex interplay between host genetics, the microbiota, and immune responses, providing potential therapeutic strategies to modulate the microbiota for improved health outcomes. Full article

Enterobiasis, caused by the nematode Enterobius vermicularis, remains a widespread public health issue, yet data regarding its genetic structure in Southeast Europe are scarce. This study presents the first molecular and phylogenetic characterization of E. vermicularis isolates from Bulgaria. Between 2022 and 2025, perianal tape test samples were collected from 128 individuals (92.2% of whom were children) with enterobiasis from 17 regions of the country. Molecular identification was performed via nested PCR targeting a 324 bp fragment of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, followed by Sanger sequencing. Phylogenetic relationships were analyzed using Maximum Likelihood (IQ-TREE), and population genetic indices were calculated using DnaSP v6. Phylogenetic analysis revealed that all 128 Bulgarian isolates belong to genotype B, clustering closely with sequences from other European and Asian countries. Genetic diversity analysis showed remarkably low variation, with a haplotype diversity (Hd) of 0.1507 ± 0.0416 and a nucleotide diversity (π) of 0.00082 ± 0.00015. Among the 11 identified haplotypes, a single dominant haplotype (Hap_1) accounted for 92.2% of all samples and was distributed across all sampled geographic regions. Tajima’s D was significantly negative (−2.314, < 0.05), suggesting a recent population expansion or purifying selection. The dominance of genotype B and the extremely low genetic diversity suggest a recent introduction or clonal expansion of E. vermicularis in Bulgaria. These findings provide essential baseline data for monitoring transmission dynamics and implementing effective control strategies in the Balkan region. Full article

Bursaphelenchus xylophilus (PWN), a highly destructive invasive forest pest, has expanded northward in China, even colonizing cold regions, implying evolved low-temperature tolerance. To explore its cold adaptation mechanisms, we selected PWN isolates from diverse origins, screened cold-tolerant strains via low-temperature stress assays, and conducted integrative transcriptomic and metabolomic analyses. We also compared invasive and native populations to clarify adaptive pattern differentiation. The results showed that northern Chinese isolates had significantly higher survival rates, with cold tolerance closely linked to lysophosphatidylethanolamine (LysoPE). Silencing the LysoPE-related gene BX02G0260 markedly elevated nematode mortality under low temperatures. Unlike native populations, invasive PWN may have developed a cold adaptation strategy centered on genetic material protection, with xanthosine as a key metabolite. These findings provide critical molecular insights into invasive species’ rapid cold adaptation in novel environments. Full article

Cyst nematodes of the genus Heterodera are important plant-parasitic nematodes that cause significant crop losses worldwide but are often overlooked due to their non-specific symptoms and complex biology. This study assessed Heterodera diversity in Portugal using an integrative molecular approach based on four genetic markers (mtCOI, 18S rDNA, ITS, and 28S rDNA). Five valid species were identified: Heterodera cruciferae, H. mani, H. schachtii, H. trifolii, and H. zeae, with H. mani reported for the first time in the country. A distinct taxon from Coimbra (central Portugal) may represent a new or unsequenced species, highlighting gaps in reference datasets. Among the markers, mtCOI was the most effective, though some taxa remained unresolved. These results reinforce the value of multi-marker approaches, contribute with new sequences, and improve diagnostic capability for nematode management. Full article

The increasing reliance on imported fish products in Kazakhstan raises concerns about the presence of fish-borne parasitic infections, particularly zoonotic helminths that pose risks to public health. This study aimed to assess the diversity and prevalence of helminths in commercially imported marine fish using both traditional and molecular diagnostic methods. A total of 670 specimens representing 17 fish species were collected from retail markets in Astana, Almaty, and Karaganda. Macroscopic inspection and muscle compression techniques were used to detect larval parasites, followed by DNA extraction and PCR amplification targeting the ITS-2, 5.8S, 18S rRNA, and mitochondrial COX gene regions. Sequencing and phylogenetic analysis confirmed the presence of cestodes (Eubothrium crassum, Hepatoxylon trichiuri, Nybelinia surmenicola), acanthocephalans (Echinorhynchus gadi), and nematodes, with a predominance of zoonotic species from the Anisakidae family, including Anisakis simplex, A. pegreffii, Pseudoterranova decipiens, and Contracaecum osculatum. The highest levels of infection were detected in Atka mackerel (97.1%), herring (96.0%), mackerel (92.0%), and blue whiting (88.1%), while the lowest rates were recorded in smelt (6.8%), flounder (10.2%), and haddock (16.0%). This is the first molecular-based survey of fish helminths in Kazakhstan and highlights the need to integrate genetic screening into food safety control systems to better protect consumers and improve parasite monitoring of imported seafood. 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

This study provides the first long-term, cross-border evaluation of Lithuanian potato (Solanum tuberosum L.) cultivars, integrating agronomic performance, tuber quality, and resistance to major pathogens across diverse environments. Field and controlled trials conducted in Lithuania and Ukraine from 2014 to 2024 revealed substantial genetic variability among 14 national cultivars, enabling their classification into five distinct maturity groups. Maincrop cultivars outperformed others in yield and starch accumulation, with ‘VB Meda’, ‘Goda’, and ‘VB Aista’ exhibiting a superior balance of productivity (up to 49 t ha⁻¹), starch content (>19%), and moderate-to-high resistance to Phytophthora infestans. A broader genetic screening of 287 accessions—including varieties, breeding lines, and hybrids—demonstrated wide diversity in phenological development, disease resistance, and reproductive traits. Notably, Ro₁ pathotype resistance was identified in 85 genotypes, predominantly with yellow-skinned tubers, while genotypic sterility in flowering and berry set was associated with both parental lineage and elevated temperatures. Although no complete immunity to P. infestans was detected, several genotypes displayed stable polygenic field resistance, suggesting the presence of horizontally inherited defense mechanisms effective under variable agroclimatic conditions. These results underscore the strategic breeding potential of Lithuanian potato germplasm for developing high-performing cultivars with enhanced resilience to late blight and nematodes and offer valuable insights for climate-adapted potato breeding in Northern and Eastern Europe. Full article

This study investigates the potential of entomopathogenic nematodes (EPNs) as biological control agents by exploring their occurrence and diversity in Amazcala, Querétaro. The aim was to characterise their distribution and evaluate their pathogenicity against insect pests. Soil samples were collected from various agricultural lands, followed by laboratory isolation and the molecular identification of EPN species. Morphological and genetic analyses confirmed the presence of several species with distinct pathogenic profiles. Pathogenicity assays using the larval stages of Galleria mellonella and Tenebrio molitor revealed that Heterorhabditis bacteriophora and Heterorhabditis atacamensis exhibited significant virulence, with Galleria mellonella being more susceptible. Among the 12 recovered EPN isolates, three strains—AMZX05 (Heterorhabditis atacamensis), AMZX10 (Heterorhabditis bacteriophora), and AMZX13 (Heterorhabditis atacamensis)—demonstrated particularly high pathogenic potential. These strains represent promising candidates for biological control and could contribute to sustainable integrated pest management (IPM) strategies. Further research is recommended to optimise their application across diverse agroecosystems. Full article

Efficient new methods are needed to support initiatives to reduce, refine, and/or replace toxicity testing in vertebrates. 5-fluorouracil (5FU), hydroxyurea (HU), and ribavirin (RV) are mammalian teratogens. Skeletal, endocrine organ, and cardiac effects are often associated with teratogenesis, and a simple nematode like C. elegans lacks these systems. However, many genetic pathways required for mammalian morphogenesis have at least some conserved elements in this small, invertebrate model. The C. elegans lifecycle is 3 days. The effects of 5FU, HU, and RV on the C. elegans morphology were evaluated on day 4 post-initiation of the feeding after hatching for continuous and 24 h (early-only) developmental exposures. Continuous exposures to 5FU and HU induced increases in the incidences of abnormal gonadal structures that were significantly reduced in early-only exposure groups. The incidence of prolapse increased with continuous 5FU and HU exposures and was further increased in early-only exposure groups. Intestinal prolapse through the vulval muscle in C. elegans may be related to reported 5FU and HU effects on skeletal muscle and the gastrointestinal tract in mammals. Continuous RV exposures induced a phenotype lacking a uterus and gonad arms, as well as vulval anomalies that were largely, but not completely, reversed with early-only exposures, which is consistent with reported reversible reproductive tract anomalies after an RV exposure in mammals. These findings suggest that C. elegans can be used to detect the hazard risk from chemicals that adversely affect conserved pathways involved in organismal morphogenesis, but to determine the fit-for-purpose use of this model in chemical safety evaluations, further studies using larger and more diverse chemical test panels are needed. Full article