Search Results (147)

Root-knot nematode (Meloidogyne incognita) is a globally destructive plant-parasitic nematode that severely impedes the sustainable production of horticultural crops. Metabolic reprogramming in plant roots represents the host response to M. incognita infection that can also be exploited by the nematode to facilitate its parasitism. In this study, untargeted metabolomics was employed to analyze metabolic changes in cucumber roots following nematode inoculation, with the goal of identifying differentially accumulated metabolites that may influence M. incognita behavior. Metabolomic analysis revealed that M. incognita significantly altered the cucumber root metabolome, triggering an accumulation of lipids and organic acids and enriching biotic stress-related pathways such as alkaloid biosynthesis and linoleic acid metabolism. Among differentially accumulated metabolites, myristic acid and hexadecanal were selected for further study due to their potential roles in nematode inhibition. In vitro assays demonstrated that both metabolites suppressed egg hatching and reduced infectivity of M. incognita, while pot experiments indicated a correlation between their application and reduced root gall formation. Chemotaxis assays further revealed that both metabolites exerted repellent effects on the chemotactic migration of M. incognita J2 and suppressed the transcriptional expression of two motility-and feeding-related neuropeptides, Mi-flp-1 and Mi-flp-18. In conclusion, this study demonstrates the significant potential of differentially accumulated metabolites induced by M. incognita infection for nematode disease control, achieved by interfering with nematode chemotaxis and subsequent infection. This work also provides deeper insights into the metabolomic mechanisms underlying the cucumber-M. incognita interaction. Full article

Meloidogyne incognita (M. incognita) is a devastating root-knot nematode that parasitizes a broad range of crop species by inducing the formation of giant cells (GCs) in host roots, thereby facilitating nutrient acquisition. This process profoundly alters host sugar metabolism, yet the molecular regulators underlying sugar dynamics during infection remain poorly understood in cucumber. In this study, we investigated the role of the cucumber alkaline α-galactosidase gene (CsAGA1) in M. incognita-infected roots. Histochemical analysis of proCsAGA1::GUS transgenic lines demonstrated that CsAGA1 is spatially localized to nematode-induced feeding sites, with its expression markedly induced in GCs and phloem-adjacent tissues during infection. Functional analyses revealed that silencing CsAGA1 impaired root and gall development. CsAGA1-silenced plants exhibited increased gall numbers (per gram root) but significantly reduced root growth and smaller galls compared to controls. These results indicate that CsAGA1 is required for proper gall expansion and root growth during M. incognita infection. This study provides novel insight into the sugar-mediated regulation of host–nematode interactions, and CsAGA1 emerges as a potential target for the biological control of M. incognita. Full article

Root-knot nematodes, Meloidogyne spp., are widespread phytoparasites that cause a significant reduction in the yield of tomato Solanum lycopersicum. In the Russian Federation, where the use of chemical nematicides is limited due to environmental and toxicological risks, the cultivation of resistant varieties and hybrids remains the most effective and environmentally safe method to control Meloidogyne. In the course of this study, the resistance screening of 20 tomato varieties/hybrids and 21 mutant lines from the collection of the FSBSI FRCBPP to M. hapla was carried out using a comprehensive approach that included morphological and biochemical analysis methods. Resistance was assessed by calculating the gall formation index, the degree of root system damage, and biochemical parameters of fruits—vitamin C content and titratable acidity. In addition, molecular screening was carried out using the SCAR marker Mi23 to identify the Mi-1.2 gene, known as a key factor in resistance to a number of Meloidogyne spp. Although Mi-1.2 is not typically associated with resistance to M. hapla, all genotypes carrying this gene showed phenotypic resistance. This unexpected correlation suggests the possible involvement of Mi-associated or parallel mechanisms and highlights the need for further investigation into noncanonical resistance pathways. It was found that when susceptible genotypes were infected with M. hapla, there was a tendency for the vitamin C content to decrease, while resistant lines retained values close to the control. The presence of the Mi-1.2 gene was confirmed in 9.5% of samples. However, the phenotypic resistance of some lines, such as Volgogradets, which do not contain a marker for the Mi-1.2 gene, indicates a polygenic nature of resistance, alternative genetic mechanisms, or the possible influence of epigenetic mechanisms. The obtained data highlight the potential of using the identified resistant genotypes in breeding programs and the need for further studies of the molecular mechanisms of resistance, including the search for new markers specific to M. hapla, to develop effective strategies for tomato protection in sustainable agriculture. Full article

The root-knot nematode Meloidogyne enterolobii has emerged as a devastating pathogen in global agricultural systems. Its geographic distribution is progressively expanding from tropical to temperate zones, leading to difficulties in discerning the symptoms it causes from those of congeners such as M. incognita. Currently, some molecular diagnostic technologies (e.g., qPCR) have been established for detecting M. enterolobii, but these methods fail to meet field-based detection demands due to their reliance on laboratory-grade thermocyclers. We thus developed a method for detecting M. enterolobii based on enzyme-mediated duplex exponential amplification (EmDEA) technologies to address this issue. The EmDEA detection method demonstrated strict specificity for the target species, showing no amplification in 13 non-target nematodes or host tissue samples. Sensitivity analyses revealed detection limits of 3.6 × 10⁻⁴ ng/μL (purified DNA), 1/1000 of an individual nematode (single-organism detection), 8.97 nematodes/g sweet potato, and 4.08 nematodes/100 g soil, achieving equivalent performance to qPCR. Field validation confirmed successful on-site detection, with significantly higher nematode loads in root tissues (50.41–97.62 nematodes/g) than in rhizospheric soil (1.07–1.28 nematodes/g). The established detection method employs a 42 °C isothermal amplification technology paired with a palm-sized thermal module, enabling field-deployable detection. Its unique duplex exponential amplification mechanism achieves threshold determination 10 cycles (~10 min) faster than conventional qPCR. When integrated with rapid DNA extraction protocols, the entire workflow is completed within 40 min, improving detection efficiency. This study provides a molecular tool for the precise monitoring of M. enterolobii, offering critical support for formulating targeted control strategies. Full article

Root-knot nematodes (RKNs; Meloidogyne incognita) pose a significant threat to tomato crops, necessitating sustainable control methods. This study investigated the inoculation efficacy of co-cultured Burkholderia vietnamiensis B418 and Trichoderma harzianum T11W compared with single-strain treatments for RKNs suppression and their influence on the structure and function of the rhizosphere microbiome. Co-inoculation with B418 + T11W achieved a 71.42% reduction in the disease index, significantly outperforming single inoculations of B418 (54.46%) and T11W (58.93%). Co-inoculation also increased plant height by 38.51% and fresh weight by 76.02% compared to the RKNs infested plants control, promoting robust tomato growth. Metagenomic analysis reveals that co-inoculation enhanced bacterial diversity, with 378 unique bacterial species and a high Shannon index, while fungal diversity decreased with Trichoderma dominance (83.31% abundance). Actinomycetota (46.42%) and Ascomycota (97.92%) were enriched in the co-inoculated rhizosphere, showing negative correlations with RKNs severity. Functional analysis indicates enriched metabolic pathways, including streptomycin and unsaturated fatty acid biosynthesis, enhancing microbial antagonism. Single inoculations altered pathways like steroid degradation (B418) and terpenoid biosynthesis (T11W), but co-inoculation uniquely optimized the rhizosphere microenvironment. These findings highlight co-inoculation with B418 + T11W effectively suppressing RKNs and fostering plant health by reshaping microbial communities and functions, offering a promising approach for sustainable agriculture. Full article

Arbuscular mycorrhizal fungi (AMF) and Trichoderma spp. (T) are known as plant-beneficial fungi effective against root-knot nematodes, but their interactions in the rhizosphere are not well understood. This study examined how Meloidogyne javanica influences AMF colonization and community diversity at the root-soil interface of tomato plants. A 60-day growth chamber experiment was conducted with tomato plants grown in non-sterile agricultural soil, either infected or not with M. javanica, that received a single inoculation with AMF or Trichoderma (strains T363 or TJ15), combined AMF + T inoculations, or no inoculation (Control). Both single and combined inoculations significantly reduced root galls, eggs, and soil nematode larvae. An AMF community analysis via single-strand conformation polymorphism of the D1 region of 28S rDNA gene (Glomeraceae family) revealed that M. javanica decreased AMF diversity and altered community structure, in plants single-inoculated with AMF. However, a combined inoculation with Trichoderma appears to prevent this reduction and maintain AMF diversity. While M. javanica reduced root mycorrhizal colonization, it did not affect Trichoderma abundance. These results suggest that Trichoderma may be more resilient to nematode infection, helping stabilize AMF communities and enhance biocontrol. Thus, combining AMF and Trichoderma inoculations could better preserve root health and improve biological control effectiveness against M. javanica. Full article

Many microbial agents, such as Bacillus amyloliquefaciens, have been reported to promote the growth of plant roots, which may enhance the uptake of systemic pesticides by plant roots. Through experimental methods, such as microscopic observation and HPLC (High Performance Liquid Chromatography) detection, the colonization behavior of B. amyloliquefaciens HN11 in sweet potato rhizosphere and its effects on sweet potato growth and fosthiazate uptake were studied. The results show that B. amyloliquefaciens HN11 could effectively colonize the rhizosphere of sweet potatoes and significantly promote the growth of sweet potato roots, leading to increase the yield of sweet potatoes. Moreover, the colonization of B. amyloliquefaciens HN11 promoted the absorption of fosthiazate by sweet potato roots under drip irrigation. The control efficiency against root knot nematodes of sweet potato also improved under this management approach. In summary, drip application of fosthiazate to sweet potato roots inoculated with B. amyloliquefaciens HN11 revealed a new approach to insecticide application. This method could improve the effective utilization rate of fosthiazate and the control efficiency of root knot nematodes, help farmers increase production and income, be environmentally friendly and meet the requirements of sustainable development. This study provides new references for the application direction of microbial agents. Full article

Root-knot nematodes (RKNs; Meloidogyne spp.) are significant plant–parasitic nematodes that cause major yield losses worldwide. With growing awareness of the harmful effects of chemical pesticides on human health and the environment, there is an urgent need to develop alternative strategies for controlling RKN in agricultural fields. In recent years, implementing multiple approaches based on transcriptomics, genomics, and genome engineering, including modern platforms like CRISPR/Cas9, along with traditional genetic mapping, has led to great advances in understanding the plant–RKN interactions and the underlying molecular mechanisms of plant RKN resistance. In this literature review, we synthesize the contributions of relevant studies in this field and discuss key findings. This includes, for instance, transcriptomics studies that helped expand our understanding of plant RKN-resistance mechanisms, the overexpression of plant hormone-related genes, and the silencing of susceptibility genes that lead to plant RKN resistance. This review was conducted by searching scientific sources, including PubMed and Google Scholar, for relevant publications and filtering them using keywords such as RKN–plant defense mechanisms, host–plant resistance against RKN, and genetic mapping for RKN. This knowledge can be leveraged to accelerate the development of RKN-resistant plants and substantially improve RKN management in economically important crops. Full article

Root-knot nematode (RKN) causes severe yield loss in cucumber. Understanding the interactions of biocontrol agent–soil microbiomes and RKNs is essential for enhancing the efficacy of biocontrol agents and nematicides to curb RKN damage to cucumber. The field experiment in this work was conducted to determine the ability of Bacillus velezensis GHt-q6 to colonize cucumber plants, investigate its effect on the control of RKNs, and assess its influence on soil microbiology in the inter-root zone of cucumber plants. After 10 days post-treatment (DPT), GHt-q6-Rif could stably colonize the roots (4.55 × 10⁴ cfu·g⁻¹), stems (3.60 × 10³ cfu·g⁻¹), and leaves (3.60 × 10² cfu·g⁻¹) of cucumber. The high-throughput sequencing results suggested that the bacterial community diversity increased at the late development phase (p > 0.05). The strain GHt-q6 increased the relative abundance of beneficial bacteria (Gemmatimonadaceae, Sphingomonadaceae, Pseudomonadaceae). Throughout the complete cucumber growth period, strain GHt-q6 significantly increased soil urease, sucrase, accessible potassium, and phosphorus (p < 0.05). However, strain GHt-q6 had a minimal effect on catalase activity. At the pulling stage, strain GHt-q6 exhibited 43.35% control effect on cucumber RKNs, which was 7.54% higher than that of Bacillus subtilis. The results highlighted the significant potential of the strain GHt-q6 to manage cucumber RKNs and improve soil microecology. Hence, the applications of B. velezensis GHt-q6 can enhance the nematicidal action to curb RKN infecting cucumber. Full article

Ralstonia solanacearum is an important pathogen causing bacterial wilt in pepper (Capsicum annuum L.). The concurrent infection of R. solanacearum and root-knot nematodes (Meloidogyne spp.) exacerbates the severity of bacterial wilt in pepper. Utilizing plant endophytic bacteria to control these mixed diseases is a viable strategy. Waltheria indica L. (Sterculiaceae) is a traditional medicine plant. A total of 209 endophytic bacteria were isolated from W. indica, and Pseudomonas aeruginosa W-126 showed an efficient antagonistic effect against R. solanacearum. Based on active compound tracking principles, a compound was isolated through silica gel column chromatography and preparative HPLC combined with TLC analysis. It was identified as phenazine-1-carboxamide (PCN) by spectral techniques (ESI-MS, ¹H-NMR, ¹³C-NMR). PCN displayed excellent inhibitory activity against R. solanacearum, with an EC₅₀ of 64.16 μg/mL in vitro. In addition, it showed certain nematocide activity, with an LC₅₀ value of 118.63 μg/mL at 72 h. PCN also showed certain inhibitory activity against five other phytopathogenic bacteria. The structure−activity relationship indicated that the phenazine skeleton and acylamide groups were the key pharmacophores for the activity of phenazine-related compounds against R. solanacearum. PCN controlled the complex diseases of R. solanacearum and M. incognita in a pot experiment, with respective 51.41 and 39.80% inhibitory rates. The exploration of secondary metabolites of biocontrol bacteria can provide reference for the development of novel and efficient pesticides. Full article

Root-knot nematodes (RKNs, Meloidogyne spp.) have become the major yield-limiting biological factor in common bean production in many warmer-climate regions such as the south of Europe. Broadening the genetic base of resistance in elite common bean cultivars is the most effective and environmentally friendly method for managing this disease. Toward this goal, F₁, F₂, and F₃ populations from crosses between susceptible snap beans (Helda and Perona) and the resistant Ouro Negro cultivar were phenotyped for M. incognita and M. javanica-induced root-galling (GI) and egg mass production (EM) in controlled growth chamber infection assays. F₁ progenies showed a susceptible response to both RKN isolates, with high GI and EM values, indicating a recessive inheritance of nematode resistance. The estimates for broad-sense heritability for GI and EM in the F₂ Helda × Ouro Negro population infected with M. incognita were 0.62 and 0.54, respectively. RKN resistance in Ouro Negro is largely controlled by partial to overdominant genetic effects and that susceptibility factor leads recessive resistance. The minimum number of genes involved in nematode resistance was estimated to be about two or three. In agreement, genetic analysis of F₂ segregating populations supported duplicate recessive epistasis as the inheritance pattern involved in the resistance provided by the Ouro Negro cultivar. Ouro Negro is an important resource for broadening RKN resistance in elite common bean cultivars. Full article

Plants adapt to biotic and abiotic stresses through physiological, morphological, and genetic changes. In recent years, the fundamental roles of epigenetic mechanisms as regulators of various immune–biological processes in nematode–plant interactions have been increasingly recognized. Epigenetic control mechanisms include non-coding RNAs (ncRNAs), DNA methylation, and histone modifications. Gene expression and gene silencing play crucial roles in activated induced resistance during pathogen attacks. DNA methylation and histone modifications are linked to defense priming or immune memory, such as systemic acquired resistance (SAR). In addition, epigenetic processes play important roles in long-term defense priming, contributing to the development of immunological memory under future stress conditions. Therefore, advances in understanding epigenetic mechanisms hold considerable potential for future research on plant–nematode interactions. However, further development in the basic understanding of interactions among various stresses, the expansion of markers for epigenetic changes, and the permanence of priming are necessary to optimize its utilization in crop protection programs. In this paper, we focus on the function of epigenetic mechanisms in plant defense responses to nematode infection, specifically root-knot nematodes (RKNs). Understanding the adaptive ability of RKNs is important for developing suitable control methods. Additionally, we explore the role of epigenetic mechanisms in plant interactions with biological control agents. Full article

Root-knot nematodes Meloidogyne spp. are sedentary endoparasites that infest a wide range of plant species; they are also widely distributed, making them one of the most economically significant pests. Similarly, damage caused by Aphelenchoides fragariae can lead to substantial reductions in both crop yield and quality. This research focused on the rhizosphere of Helianthus tuberosus L. (variety Albik), grown in a Polish plantation. The experiment was conducted at the National Institute of Horticultural Research in Skierniewice, using concrete rings filled with medium sandy soil amended with 10% peat. The treatments included the following: control (no amendments), silver solution (Ag+) (120 mg/L soil), and vermicompost (Ve) (20 L of Eisenia fetida vermicompost). Each treatment was replicated four times. Compared with control, (Ve) significantly decreased the numbers of Aphelenchoides fragariae and Meloidogyne hapla, by about 48% and 31%. The application of (Ag+) led to the most significant reduction in population density in both nematode species, with A. fragariae decreasing by over 67% and M. hapla by approximately 75%. Full article

The primary strategy for managing Nacobbus aberrans has traditionally relied on synthetic chemicals. However, increasing regulatory pressure on unsafe products has led to a growing research focus on nematicides. Despite this, chemical nematicides remain more effective than other control methods. Consequently, there is a pressing need to develop novel nematicides that are both effective and environmentally safer. This study aimed to evaluate the nematocidal efficacy of various synthetic molecules against the second-stage juveniles of N. aberrans, the false root-knot nematode. A total of fifty-eight synthetic derivatives were obtained and tested in vitro at a concentration of 500 µg/mL. The results identified the AGAz family as the most promising, with AGAz-3 (LC₅₀: 52.7 µg/mL) and AGAz-4 (LC₅₀: 103.22 µg/mL) surpassing the efficacy of chitosan. Our findings emphasize the strong potential of AGAz-3 and AGAz-4 as nematocidal agents, particularly for in situ applications in agricultural settings. Additionally, AGAz-3 demonstrates potential not only as a nematocidal agent but also as an incentive for related research exploring its analogs as effective ovicidal compounds and investigating its efficacy against other phytonematodes. Furthermore, compounds from the N-Sulfonyl-hydrazone and N-acyl-hydrazone series showed efficacy (>50%), warranting additional experiments to assess their effectiveness across the most important pest phytonematodes. Full article

Plant-parasitic nematodes remain a significant challenge to agriculture and horticulture. Unfortunately, there is a lack of rapid, efficient and eco-friendly control methods. Nanomaterials, therefore, appear to be a promising source of new plant protection strategies. In the current study, two nanosystems—based on one-component (Ag) or two-component (AgZn) colloidal systems—and an aqueous solution of AgNO₃, were explored for their potential in nematode control, using Meloidogyne incognita—the most economically important root-knot nematode—as a model nematode. In vitro laboratory tests demonstrated high efficacy of all the tested compounds towards M. incognita. Incubation with an extremely low concentration of silver compounds (0.05 ppm) resulted in a 100% reduction of the M. incognita invasive larvae viability, as well as a 100% inhibition of the egg hatch process. Preliminary tests also showed no negative impact of tested compounds on seed germination. Thus, the nanosystems tested within this study offer a promising alternative to the current methods used for nematode control. Full article