Search Results (379)

MicroRNAs (miRNAs) are key post-transcriptional regulators of plant development and stress responses, with many being conserved across diverse plant lineages. In this study, we investigated the expression profiles of miRNAs and their corresponding target genes in Arachis stenosperma, a wild peanut relative that exhibits robust resistance to root-knot nematodes (RKN). Small RNA sequencing of nematode-infected roots identified 107 miRNA loci, of which 93 corresponded to conserved miRNA families and 14 represented novel candidates, designated as miRNOVO. Among these, 18 miRNAs belonging to 11 conserved families were identified as differentially expressed (DEMs). Notably, miR399 and miR319 showed the highest upregulation (logFC = 4.25 and 4.20), while miR393 and miR477 were the most downregulated (logFC = −0.83 and −0.79). Integrated analysis of miRNA and transcriptome data revealed several regulatory interactions involving key defense-related genes. These included NLR genes targeted by miR393 and miR477, hormone signaling components such as the auxin response factor ARF8 targeted by miR167, and the growth regulator GRF2 targeted by miR396. Additionally, miR408 was predicted to target laccase3, a gene involved in the oxidation of phenolic compounds, lignin biosynthesis, copper homeostasis and defense responses. Remarkably, four immune receptor genes belonging to the nucleotide-binding site leucine-rich repeat (NLR) family displayed inverse expression patterns relative to their regulatory miRNAs, suggesting miRNA-mediated post-transcriptional control during the early stages of nematode infection. These findings reveal both conserved and species-specific miRNA–mRNA modules associated with nematode resistance in A. stenosperma, highlighting promising targets for developing RKN-tolerant peanut cultivars through miRNA-based strategies. Full article

The role of the rhizosphere microbiome in naturally suppressing soilborne diseases remains a critical unknown in sustainable agriculture. We investigated this by challenging three genotypes of tomato plants grown in pre-sterilized and natural soils with three major soil-borne pathogens: Ralstonia solanacearum, Fusarium oxysporum f. sp. lycopersici, and Meloidogyne incognita. The results showed that all tomato genotypes grown in pre-sterilized soils exhibited significantly higher disease severity with all pathogens. This protective effect was linked to higher microbial diversity and the abundance of beneficial taxa like Sphingomonas and Mortierella in natural soil as a significant reduction was recorded in microbial diversity and these microbial taxa in pre-sterilized soil. Pre-sterilization shifted community assembly from deterministic processes to stochastic processes, reducing functional stability. Functional predictions further demonstrated an enrichment of growth-promoting and disease-suppressive traits in natural soils, while sterilized soils favored pathogen-associated functions. Co-occurrence network analysis confirmed that the natural microbiome formed a more complex and robust microbial network, likely increasing its resistance to pathogen invasion. Notably, the reintroduction of soil microbiota from healthy plants partially restored tomato resistance to the three pathogens. These findings highlight the key role of stable rhizosphere microbial communities in suppressing soil-borne diseases and emphasize the importance of conserving microbial diversity and functional stability for plant health and sustainable agriculture. Full article

A low-scale Food Waste Compost (FWC1), characterized by optimal physic-chemical parameters and high organic matter percentages, was used as a fertilizer and a bio-stimulant for vegetable plants. Groups of treated plants were inoculated with active juveniles of root-knot nematodes to detect the effect on plant defense. Optimal amounts of compost mixed with soil increased plant biomass 30% compared to untreated plants. Moreover, when plants were inoculated, treated roots contained about 50% less sedentary forms (SFs) of nematodes and a lower reproduction rate of the parasites than untreated plants. Although the performance of FWC1 as defense activator was similar to other microbiome-generating commercial formulations, the compost was found to be the best fertilizer in both un- and inoculated plants. Diffuse root colonization by arbuscular mycorrhizal fungi (AMF) was observed after treatments with FWC1. FWC1 water extracts did not show any toxic effect on living nematode juveniles. Expression of the marker gene of immune response PR4b was found to be 3–5-fold higher in the roots of inoculated plants treated with FWC1 with respect to untreated plants, thus indicating that FWC1 primes plants against RKNs (root-knot nematodes, Meloidogyne incognita (Kofoid White) Chitw). Data are reported to associate immunization of plants with mycorrhization occurring in FWC1-treated plants. The proposed compost is indicated as having optimal performance both as a bio-fertilizer and a bio-stimulant. Full article

Eutrema japonicum is a perennial herb belonging to the Eutrema genus in the crucifer family. In recent years, numerous substances with notable pharmacological activities have been successfully isolated from E. japonicum. Despite significant advancements in related research, the efficacy of the rhizome extract of E. japonicum against root-knot nematodes remains unknown. In this study, the rhizome extract of E. japonicum was used as raw material to demonstrate the inhibitory and nematicidal effects of the extract on Meloidogyne enterolobii. The results showed that the LC₅₀ of the E. japonicum rhizome extract on second-stage juveniles (J2s) was 69.590 mg/mL and 22.336 mg/mL at 24 h and 48 h after treatment, respectively. The mortality rate of J2s reached 88.93% at 48 h post-treatment when the concentration was 200 mg/mL, and the inhibition rate of single-egg hatching reached 88.14%. This study analyzed the chemical composition of the ethanol extract of E. japonicum, and 10 organosulfur compounds and lipid compounds with insecticidal and antibacterial effects were preliminarily screened out. Among them, sec-butyl isothiocyanate and geraniol were further investigated for their nematicidal activity, demonstrating high efficacy against M. enterolobii. Moreover, we conducted network pharmacology analysis and RT-qPCR analysis to predict the potential inhibitory mechanisms of sec-butyl isothiocyanate and geraniol on M. enterolobii. These findings offer a scientific foundation and theoretical framework for utilizing E.japonicum as a potential raw material for developing novel natural plant nematicides. Full article

Root-knot nematodes (RKNs) of the genus Meloidogyne spp., are among the most economically important groups of plant-parasitic nematodes worldwide, causing significant economic losses through yield reduction across a wide range of crops. In Croatia, although the presence of Meloidogyne spp. has been documented for decades, data at the species level was limited. As accurate identification is crucial for implementation of effective management strategies, we attempted to fill this gap. This study presents the results of a national survey of RKNs affecting potato crops as well as an early warning programme targeting vegetable crops, conducted across Croatia between 2022 and 2024. Nematodes were identified using morphological analyses (female perineal patterns and second-stage juveniles) and molecular methods (PCR with group-specific and species-specific primers, as well as DNA sequencing). Meloidogyne spp. were detected in 61 out of 210 samples, corresponding to an infestation rate of 29%. Four species were identified: M. incognita, M. hapla, M. arenaria, and M. javanica. Notably, M. incognita and M. javanica are reported here for the first time in Croatia. These results provide updated insights into the distribution and identity of RKNs in Croatia, thereby establishing a foundation for the implementation of sustainable management strategies. Full article

Meloidogyne enterolobii, is a devastating pathogen capable of overcoming conventional resistance genes. This study presents the first investigation into targeting the chitin synthase gene Me-chs-1 in M. enterolobii using host-induced gene silencing (HIGS). Our results demonstrate that HIGS effectively suppresses Me-chs-1 expression, leading to a drastic reduction in nematode reproductive capacity, with the most effective transgenic line showing over 82% decrease in total egg production. Additionally, notable developmental deformities were observed in the nematodes. This study confirms Me-chs-1 as a promising target for controlling M. enterolobii and lays a solid foundation for developing novel resistance breeding strategies and eco-friendly nematicides. Full article

Plant-parasitic nematodes (PPNs) pose a significant threat to agricultural production and global food security. To mitigate this challenge, quantitative trait locus (QTL) mapping and genome-wide association studies (GWAS) have been extensively employed in crop resistance breeding research. These methods have identified resistance-related genes and genetic markers, offering a solid scientific basis and practical tools for resistance breeding. This review summarizes recent advances in QTL and GWAS applications for enhancing resistance to cyst nematodes (Heterodera glycines, H. filipjevi, and H. avenae), root-knot nematodes (Meloidogyne graminicola and M. incognita), and root-lesion nematodes (Pratylenchus spp.). It also evaluates the commercial deployment of resistance genes, discusses integrated breeding strategies, and highlights future research directions toward developing durable nematode-resistant crops. Full article

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

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

Proteases (EC 3.4) are hydrolytic enzymes widely used in biotechnological processes, representing about 60 to 70% of the global industrial enzyme market. Edible mushrooms of the genus Pleurotus stand out as excellent producers of these enzymes, in addition to exhibiting high nutritional value and medicinal properties. The proteases produced by these species exhibit broad adaptability to different experimental conditions, including variations in optimal pH and temperature, as well as distinct sensitivities to inhibitors. The production of these enzymes can be intensified by solid-state fermentation (SSF) using low-cost agro-industrial substrates, such as wheat bran, which favors sustainable applications aligned with the circular economy. Parameters such as carbon/nitrogen (C/N) ratio, medium pH, cultivation time, and inoculum age directly influence enzyme productivity. Proteases from Pleurotus spp. show high potential in the biochemical control of parasites such as Meloidogyne incognita, Haemonchus spp., Taenia solium, and Moniezia sp., catalyzing the degradation of the cuticle or eggshell. Other biotechnological applications include milk coagulation, thrombolytic therapies, keratin bioconversion, increased protein digestibility, and use as additives in the food, detergent, and pharmaceutical industries. Full article

Root-knot (Meloidogyne spp.) and false root-knot (Nacobbus aberrans) nematodes limit greenhouse tomato productivity. The effectiveness of integrating pre-plant biofumigation with post-plant chemical, biological, and botanical inputs was assessed under commercial conditions. A split-plot trial (2019) contrasted biofumigated and non-biofumigated whole plots (50 t ha⁻¹ of sorghum residues plus poultry and sheep manures) and 13 subplot treatments (fluopyram, Purpureocillium lilacinum, Pochonia chlamydosporia, Trichoderma viride, Tagetes erecta, and plant oil formulations). Nematodes were sampled 0, 60, and 120 days after transplanting, and the area under the nematode population curve (AUNPC), area under the root-damage curve (AURDC), and yield were analyzed. Biofumigation reduced pre-transplant N. aberrans populations by 86% and lowered the AUNPC by 39% relative to the non-biofumigated treatment; the whole-plot yields did not differ. Meloidogyne incognita remained at a very low density throughout. Among the subplot treatments, fluopyram decreased the AURDC by ≈22% and more than doubled the yield (63 vs. 26 t ha⁻¹; +142%), while the AUNPC of N. aberrans was unchanged. Biological and botanical packages reduced damage indices in some cases but did not increase the yield. No whole-plot × subplot interaction was detected for the yield. The results indicate that sorghum-based biofumigation, complemented by a low-risk nematicide at transplanting, can be embedded in integrated nematode-management programs for greenhouse tomato. Full article

Proteins containing the SQS-PSY domain, which include squalene synthetase (SQS), phytoene synthetase (PSY), and NDUFAF6, are functionally important and widely distributed in plants and animals. However, they have not been previously reported in nematodes. In this study, we identified a gene (Minc31999) encoding an SQS-PSY domain-containing protein in the root-knot nematode Meloidogyne incognita. In silico comparison and enzymatic assays of the recombinant protein indicated that this nematode protein is a putative NDUFAF6 homolog. Phylogenetic analysis revealed that this protein is evolutionarily conserved within the Nematoda phylum. RT-qPCR analysis showed that Minc31999 is highly expressed during the early infection stage of M. incognita. Targeting the nematode gene Minc31999 via host-induced gene silencing (HIGS) significantly hindered nematode development and virulence. In contrast, heterologous expression of Minc31999 in Arabidopsis thaliana disrupted normal plant development and increased host susceptibility to nematode infection. Transcriptomic profiling (RNA-seq) of these transgenic plants prior to infections showed a widespread differential expression of genes across multiple metabolic pathways. We propose that this nematode SQS-PSY domain-containing protein may function as an effector that rewires host secondary metabolism to establish a parasitic relationship. Our study elucidates a novel strategy in nematode–plant interactions and advances our understanding of the functional evolution of SQS-PSY domain-containing proteins. 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

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

Plant Parasitic Nematodes (PPNs), such as Meloidogyne incognita, cause significant agricultural losses worldwide. Conventional nematicides like methyl bromide are being phased out due to environmental and health concerns, prompting the search for safer alternatives. In previous studies, chalcones 17, 25, and 30, flavonoid compounds, were shown to effectively kill the model nematode Caenorhabditis elegans at concentrations of 10⁻⁴ M. However, the potential of these chalcones to act synergistically at lower concentrations has not been explored. In this study, the nematicidal efficacy of chalcones 17, 25, and 30 was evaluated individually and in combination at concentrations as low as 10⁻⁶ M. The results demonstrate a strong synergistic effect, with combinations achieving 90–100% mortality in C. elegans within 3 days. Additionally, the combination index method revealed significant toxic effects against M. incognita with chalcones 17 and 30 in binary and ternary combinations. To assess the effects of these chalcones on nontarget organisms, chalcones were also tested for antimicrobial activity against soil bacteria; analysis of soil microbiota using 16S rRNA sequencing indicated that chalcones did not significantly disrupt microbial populations. Furthermore, tests on human pluripotent stem cells (hPSCs) reveal no major effects on the viability of these cells at concentrations as high as the concentrations needed to kill nematodes. These findings highlight the potential of chalcones 17, 25, and 30 for effective nematode control without harming soil bacteria or human cells. Full article