Search Results (109)

Pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, is a devastating pine disease that is characterized by rapid transmission, high lethality, and limited control options. In our previous study, the fucosyltransferase gene (fut) which encoded fucosyltransferase (FUT) was found to be a putative virulence determinant in PWN, which regulates pathogenicity of nematodes. To investigate the functional role of the fut gene in PWN, a comprehensive analysis was conducted to understand its molecular structure and biological activity. The full-length open reading frame (ORF) of fut was amplified using reverse transcription PCR (RT-PCR) and successfully ligated into the pET-28a expression vector. Heterologous expression of the recombinant FUT was achieved in Escherichia coli Rosetta (DE3) through induction with 1.0 mM isopropyl-β-D-thiogalactoside (IPTG), followed by purification via nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. Biochemical characterization revealed that the recombinant FUT exhibited optimal enzymatic activity at 30 °C and pH 8.0, respectively. Furthermore, RNA interference (RNAi) validated by RT-qPCR was used to explore the biological functions of fut in PWN, and results indicated that downregulation of the fut gene could significantly reduce the vitality, reproduction, pathogenicity, development, and lifespan of PWN. Furthermore, gallic acid as an inhibitor of FUT displayed a strong inhibitory effect on recombinant FUT activity and nematicidal activity against PWNs in vitro and could alleviate the wilt symptom of pine seedlings inoculated with PWNs at a concentration of 100 μg/mL, indicating that it has the potential to be a novel nematicide. Collectively, these results establish fut as a critical virulence determinant in PWN and highlight its potential as a molecular target for controlling pine wilt disease. Full article

Pine wilt disease, transmitted primarily by Monochamus alternatus (Hope, 1842) adults, causes severe ecological and economic losses globally. Conventional chemical controls face challenges of resistance and non-target toxicity. This study identified Beauveria bassiana (Bals.-Criv.) Vuill. strain B4 as a high-virulence biocontrol agent against adult M. alternatus. Laboratory bioassays compared four strains (B1–B4), with B4 exhibiting rapid lethality (LT₅₀ = 6.61 days at 1 × 10⁸ spores/mL) and low median lethal concentration (LC₅₀ = 9.63 × 10⁵ spores/mL). Critically, B4 infection induced significant behavioral suppression, including reduced appetite and mobility prior to death. In forest trials, pheromone-enhanced nonwoven fabric bags impregnated with B4 spores reduced trap catches by 66.4% within one month, with effects persisting for over a year without reapplication. The slow-release carrier system enabled continuous spore dissemination and sustained population suppression. These results demonstrate that B4’s dual action—rapid lethality and behavioral disruption—provides an effective, eco-friendly strategy for sustainable pine wilt disease management. 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

Pine wilt disease (PWD), transmitted by Monochamus alternatus (JPS), poses a severe threat to global pine forests. Although the entomopathogenic fungi Beauveria bassiana (Bb) and Metarhizium anisopliae (Ma) represent environmentally friendly biocontrol alternatives, their practical application is limited by inconsistent field performance and an incomplete understanding of host–pathogen interactions. We employed dual RNA-seq at the critical 48 h infection time point to systematically compare the transcriptional responses between JPS and Bb/Ma during infection. Key findings revealed distinct infection strategies: Bb preferentially induced autophagy pathways and modulated host carbohydrate metabolism to facilitate nutrient acquisition, triggering corresponding tissue degradation responses in JPS. In contrast, Ma primarily co-opted host amino acid and sugar metabolic pathways for biosynthetic processes, eliciting a stronger immune defense activation in JPS. Notably, the mTOR signaling pathway was identified as a key regulator of the differential host responses to various entomopathogenic fungi. Further functional validation-specifically, the application of a chemical inhibitor and RNAi targeting mTOR in JPS-confirmed that mTOR inhibition selectively enhanced Bb-induced mortality in JPS without affecting Ma virulence. Our findings reveal the molecular determinants of host–pathogen specificity in PWD biological control and indicate that mTOR regulation could serve as an effective strategy to improve fungal pesticide performance. 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

Pine wilt disease (PWD) is an economically important disease. With the increasing temperature caused by climate change, there is a concern that it may expand to regions currently at low risk, cause more serious ecological harm and economic losses in China. The pinewood nematode has an optimal temperature range for development, and historical meteorological conditions, particularly temperature, can influence its current occurrence through time-lagged effects. Lag effect is a temporally delayed effect. In order to investigate the threshold effect and lag effect of temperature on PWD, we collected province-level occurrence data in China and explored the threshold effect, lag effect, and spatial heterogeneity mechanism using a distributed lag non-linear model. The results show that temperature has a significant threshold effect and lag effect on PWD. The threshold temperatures and lag periods vary from 19.5 °C to 25.1 °C and from 1 to 3 months in different provinces in the study area. The threshold temperature shows significant spatial heterogeneity and is positively correlated with the average temperature. This study provides a theoretical basis for the prevention and control of PWD, as well as protection of forest ecological security. Full article

Pine wilt disease, a devastating disease severely impacting pine ecosystems, is caused by the pinewood nematode Bursaphelenchus xylophilus (Steiner & Bührer, 1934) Nickle, 1970 (Nematoda: Parasitaphelenchidae). Controlling B. xylophilus is crucial for preventing and managing pine wilt disease. Recently discovered novel nematocidal lectins could provide more advantageous materials for utilizing genetically engineered bacteria to control this pathogen. Therefore, this study focuses on identifying novel nematocidal toxins within B. xylophilus lectins. Overall, we obtained twenty-one galectin, one L-type lectin (LTL), and three chitin-binding domain (CBD) genes by screening the B. xylophilus genome database; these genes were successfully expressed proteins. The bioassay results indicated that Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, and BxLTL1 induced mortality rates exceeding 50% in B. xylophilus. Notably, Bxgalectin4 showed the strongest nematocidal activity, causing 88% mortality in the treated nematode population. The enzyme-linked immunosorbent assays further demonstrated that Bxgalectin3 (K_d = 8.992 nM) and Bxgalectin4 (K_d = 9.634 nM) had a higher binding affinity to GPI-anchored proteins from B. xylophilus. Additionally, Bxgalectin2 (K_d = 16.50 nM), Bxgalectin9 (K_d = 16.48 nM), and BxLTL1 (K_d = 24.34 nM) can bind to the GPI-anchored protein. This study reports, for the first time, that lectins endogenous to B. xylophilus exhibit nematocidal activity against their own species. These findings open up the possibility of using nematode lectins as potent control agents in the biological control of B. xylophilus. Full article

A possible tactic to survey and control Pine Wilt Disease is the use of semiochemical-baited traps to capture the insect-vector, the pine sawyer Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae). The most common chemical lure used is the Galloprotect Pack, which includes the aggregation pheromone ([2-undecyloxy] ethanol), a host monoterpene (α-pinene), and bark-beetle pheromones (ipsenol and 2-methyl-3-buten-1-ol). This lure also attracts non-target species, including bark beetles (Coleoptera: Curculionidae: Scolytinae) that use ipsenol (Ips sexdentatus (Boerner)) and 2-methyl-3-buten-1-ol (Orthotomicus erosus (Wollaston)) as pheromones, but also large numbers of their natural enemies, Temnoscheila caerulea (Olivier) (Coleoptera: Trogossitidae), Aulonium ruficorne (Olivier) (Coleoptera: Colydiidae), and Thanasimus formicarius (L.) (Coleoptera: Cleridae), and other saproxylic insects (Coleoptera: Cerambycidae). These catches cause a decrease in biodiversity of the forest insect communities, and the removal of predatory insects may favour bark beetle outbreaks. Thus, our project objective was to test trap modifications to try to reduce catches of non-target insects. Modifying the multifunnel trap’s collection cup by placing a 0.5 cm mesh in the drainage hole allowed the escape of all predator beetles (Cleridae, Trogossitidae, Colydiidae, and Histeridae) in 2020, and retained only two Trogossitidae in 2021, against 249 specimens caught in the non-modified collection cup. This simple modification thus allowed the escape of almost all predators, while maintaining the traps’ efficiency at catching the target species, M. galloprovincialis. Full article

Pine wilt disease (PWD) is a severe forest disease caused by the infestation of pine wood nematodes. Due to its short disease cycle and strong transmission ability, it has caused significant damage to China’s forestry resources. To achieve large-scale monitoring of PWD, this study utilized machine learning/deep learning algorithms with Sentinel-1/2 images in the Google Earth Engine cloud platform to implement province-wide PWD monitoring in Anhui Province, China. The study also analyzed the spatial distribution of PWD in Anhui Province from two perspectives—spatiotemporal patterns and influencing factors—aiming to investigate the spatiotemporal evolution patterns and the impact of influencing factors on the occurrence of PWD. The results show that (1) the random forest model exhibited the strongest performance, followed by the CNN model, while the DNN model performed the worst. Using the RF model to monitor PWD and calculate the affected area in Anhui Province from 2019 to 2024 yielded errors within 30% compared to official statistics. (2) PWD in Anhui Province showed a clear clustering trend, with global Moran’s indices all exceeding 0.79 from 2019 to 2024. The LISA map revealed a spread pattern from south to north and from west to east. (3) Topographic and temperature factors had the greatest influence on PWD distribution. SHAP analysis indicated that topographic and climatic factors were the primary drivers of PWD-affected areas, with slope and temperature being the two most significant contributing factors. This study helps to rapidly and accurately identify outbreak areas during epidemics and enables precise quarantine measures and targeted control efforts. Full article

Pine wilt disease poses a significant threat to pine forests worldwide, necessitating efficient and accurate detection of dead pine wood for effective disease control and forest management. Traditional deep learning methods based on supervised closed-set paradigms often struggle to address unknown interfering objects, causing false positives, missed detection, and increased annotation burdens. To overcome these challenges, we propose SS-OPDet, a semi-supervised open-set detection framework that leverages a small amount of labeled data along with abundant unlabeled data. SS-OPDet integrates a Weighted Multi-scale Feature Fusion module to dynamically integrate global- and local-scale features, thereby significantly improving representational accuracy for dead pine wood. Additionally, a Dynamic Confidence Pseudo-Label Generation strategy categorizes predictions by confidence level, effectively reducing training noise and maximizing the use of reliable unlabeled data. Experimental results from 7733 UAV images demonstrate that SS-OPDet achieves an average precision (${AP}_K$) of 84.73%, a recall ($R_K$) of 94.48%, an Absolute Open-Set Error (AOSE) of 271 and a Wilderness Impact (WI) of 0.0917%. Cross-region validation further confirms the robustness and generalization capability of the proposed framework. The proposed method offers a cost-effective and accurate solution for timely detection of pine wilt disease, providing substantial benefits to forest monitoring and management. Full article

Pine wilt disease (PWD), caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus), poses a significant threat to global pine forests and calls for the development of innovative management strategies. Microbial control emerges as an effective, cost-efficient, and environmentally sustainable approach to eliminate the damage from PWD. This review consolidates molecular mechanisms in the microbiological control of PWD, which focus on three core strategies: microbial control activity against PWN, biological control of vector insects, and the enhancement of host tree resistance to nematode infections. The review thoroughly evaluates integrated control strategies in which microbial control is used in traditional management practices. Recent studies have pinpointed promising microbial agents for PWN control, such as nematophagous microorganisms, nematicidal metabolites, parasitic fungi that target vector insects, and microbes that boost plant resistance. In particular, the control potential of volatile organic compounds (VOCs) produced by microorganisms against PWN and the enhancement of pine resistance to PWN by microorganisms were emphasized. Moreover, we assessed the challenges and opportunities associated with the field application of microbiological control agents. We emphasized the feasibility of multi-strategy microbial integrated control, which provides a framework for future studies on microbial-based PWD control strategies. Full article

Pine wilt disease (PWD) is characterized by rapid transmission, high mortality rates, and difficulty in control, resulting in severe and destructive impacts on both the ecological environment and socioeconomic development in China. Due to the lack of significant symptoms in infected trees during the early stages of the disease, improving the accuracy of early detection has become a major challenge in PWD monitoring. In recent years, the rapid advancement of UAV-based hyperspectral remote sensing technology has provided a promising approach for the early detection of PWD. In this study, we selected classic canopy pigment and moisture content indices to construct a set of recognition indicators. The optimal canopy pigment index (CI) and canopy moisture content index (WASCOSBNDI) were then chosen through significance testing and derivative analysis. Based on the asynchronous variations in canopy moisture and pigment content during the development of PWD, the CI, WASCOSBNDI, and CI-WASCOSBNDI models were developed using a multi-threshold segmentation method to identify trees at different stages of infection. The results demonstrate that the CI-WASCOSBNDI model achieved the highest accuracy in detecting infection stages, with an overall classification accuracy of 92.78%. In comparison, the CI and WASCOSBNDI models achieved classification accuracies of 81.34% and 89.84%, respectively. For the early stage infected trees, which are the primary focus of this study, the CI-WASCOSBNDI model exhibited the best performance with an accuracy rate exceeding 70%, significantly outperforming the other models. Furthermore, the timing of infection in early stage trees significantly influenced the model’s detection accuracy, with trees closer to the disease outbreak period being more easily identified. These findings provide a reference for the accurate early monitoring of PWD using UAV hyperspectral imagery. Full article

Glutamate-gated chloride channels (GluCls), a class of ion channels found in the nerve and muscle cells of invertebrates, are involved in vital life processes. Bursaphelenchus xylophilus, the pathogen of pine wilt disease, has induced major economic and ecological losses in invaded areas of Asia and Europe. We identified 33 GluCls family members by sequence alignment analysis. A subsequent bioinformatic analysis revealed the physicochemical properties, protein structure, and gene expression patterns in different developmental stages. The results showed that GluCls genes are distributed across all six chromosomes of B. xylophilus. These proteins indicated a relatively conserved structure by NCBI-conserved domains and InterPro analysis. A gene structure analysis revealed that GluCls genes consist of 5 to 14 exons. Expression pattern analysis revealed BxGluCls were extensively involved in the development of second instar larvae of B. xylophilus. Furthermore, BxGluCls15, BxGluCls25, and BxGluCls28 were mainly associated with the development of eggs of B. xylophilus. BxGluCls12, BxGluCls18, and BxGluCls32 were predominantly linked to nematode resistance and adaptation. Investigation the structure and expression patterns of BxGluCls is crucial to understand the developmental trends of B. xylophilus. It also helps identify molecular targets for the development of biopesticides or drugs designed to control this nematode. Full article

Pine wilt disease, caused by Bursaphelenchus xylophilus, poses severe ecological and economic threats to coniferous forests. This study isolated two fungal (Arthropsis hispanica, Penicillium sclerotiorum) and two bacterial (Bacillus amyloliquefaciens, Enterobacter hormaechei) strains from Pinus massoniana rhizospheres, evaluating their biocontrol potential against pine wood nematodes. Molecular characterization confirmed strain identities. In vitro assays demonstrated that combined fermentation filtrates of CSX134+CSZ71 and CSX60+CSZ71 significantly enhanced plant growth parameters (height, biomass) and root-associated soil enzyme activities (urease, acid phosphatase) in P. massoniana. Treated plants exhibited elevated defense enzyme activities and upregulated defense-related gene expression. The treatments achieved 75.07% and 69.65% nematode control efficacy, respectively, compared to controls. These findings highlight the potential of microbial consortia in activating systemic resistance and suppressing pine wilt disease through the dual mechanisms of growth promotion and defense induction. Full article

Plants, as producers in ecosystems, are an integral part of biodiversity in terms of their species diversity. Plant diversity not only enhances the quality of ecosystem services, but also provides habitat for a wide range of plants and animals. The invasion of pine wilt disease (PWD) has posed a significant threat to plant diversity in China, but it is not clear whether this threat would be significantly different in natural and planted forests. In this study, we collected a long time series of refined forest subcompartment data on PWD occurrence and plant diversity sample survey data to analyze the loss and recovery time of plant diversity in China caused by PWD invasion, especially the degree of impact on plant diversity in natural and planted forests. The results showed that after PWD invasion, the plant diversity levels of China’s national, natural, and planted forests reached a minimum in the third year of invasion, with a loss of 9.1%, 6.46%, and 9.82%, respectively, relative to the pre-invasion levels. Starting from the third year of invasion, the plant diversity levels of the three recovered gradually at different rates, among which there was a significant difference in the speed of recovery between natural forests and planted forests, which took two and three years to recover to the original level of plant diversity, respectively. This study revealed the differences in the response of plant diversity to PWD invasion between natural and planted forests and provided a theoretical basis for local governments and managers in preventing and controlling PWD and protecting plant diversity. Full article