Next Article in Journal
Integrated Analysis of Phenotypic, Physiological, and Biochemical Traits in Betula platyphylla Sukaczev Under Cold Stress Conditions
Previous Article in Journal
The Role of Tree Size in Root Reinforcement: A Comparative Study of Trema orientalis and Mallotus paniculatus
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Forests
Volume 16
Issue 7
10.3390/f16071177
forests-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Nematocidal Activity and Intestinal Receptor-Binding Affinity of Endogenous Lectins in Bursaphelenchus xylophilus (Pinewood Nematode)

by
Songqing Wu
1,2,*,†,
Yunzhu Sun
1,2,3,†,
Zibo Li
3,4,
Xinquan Li
1,2,
Wei Yu
5 and
Yajie Guo
1,3,*
1
State Key Laboratory of Agricultural and Forestry Biosecurity, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
2
Conservation and Utilization of Natural Biological Resources, Fujian Provincial University Engineering Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
3
Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Agriculture and Forestry University, Fuzhou 350002, China
4
College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
5
Guizhou Institute of Biology, Guizhou Academy of Sciences, Guiyang 550009, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Forests 2025, 16(7), 1177; https://doi.org/10.3390/f16071177
Submission received: 7 June 2025 / Revised: 12 July 2025 / Accepted: 15 July 2025 / Published: 16 July 2025
(This article belongs to the Section Forest Health)
Browse Figures
Versions Notes

Abstract

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 (Kd = 8.992 nM) and Bxgalectin4 (Kd = 9.634 nM) had a higher binding affinity to GPI-anchored proteins from B. xylophilus. Additionally, Bxgalectin2 (Kd = 16.50 nM), Bxgalectin9 (Kd = 16.48 nM), and BxLTL1 (Kd = 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.

1. Introduction

Pine wilt disease, caused by the pathogenic nematode Bursaphelenchus xylophilus (Steiner & Bührer, 1934) Nickle, 1970 (Nematoda: Parasitaphelenchidae), is a devastating forest disease that originated in North America and has spread globally since the 20th century, severely impacting pine ecosystems in Japan, China, Korea, and Europe [1]. According to the 2023 pine wilt disease epidemic area (No. 7 in 2023) published by the State Forestry and Grassland Administration of China, 19 provinces (autonomous regions and municipalities) in mainland China were affected by pine wilt disease during this year [1]. The economic loss caused by this disease has reached CNY 19.5 billion a year [2]. B. xylophilus exhibits a remarkable adaptive capacity, capable of causing host-tree mortality within three months post-infection and devastating hundreds of hectares of pine forests within 3–5 years [3]. Accordingly, controlling B. xylophilus is crucial for preventing and managing pine wilt disease.
Among the various control methods for B. xylophilus, using insecticidal toxins to construct genetically engineered bacteria for pest control offers many advantages, such as high safety and environmental friendliness [1,4]. However, there are currently few studies on insecticidal toxins effective against B. xylophilus. Among the toxins with insecticidal activity, such as Bacillus thuringiensis (Bt) toxins, lectins, and animal toxins, a large amount of research has shown that lectins exhibit toxicity against a wide range of insects, including Coleoptera, Diptera, Lepidoptera, Hymenoptera, and Homoptera [5,6,7,8,9]. Therefore, if novel anti-pinewood nematode proteins can be identified from lectins, they could provide more effective materials for controlling B. xylophilus using genetically engineered bacteria.
Lectins are a class of carbohydrate-binding proteins and can be classified into plant lectins, animal lectins, and microbial lectins based on their origin [10]. Lectins produced by the nematodes themselves are termed endogenous lectins, while those from other sources are referred to as exogenous lectins. Among them, endogenous lectins primarily participate in the insect’s immune responses [11]. In contrast, exogenous lectins can bind to digestive enzymes or transport proteins secreted in the insect gut, disrupting intestinal tissues and ultimately killing the insect [12,13]. It has been demonstrated that various exogenous lectins can exhibit nematocidal activity [14,15,16]. Qi et al. found that Pinellia ternata (Thunb.) Makino (Alismatales: Araceae) agglutinin (PTA) and Lycoris radiata (L’Hér.) Herb. (Asparagales: Amaryllidaceae) agglutinin (LRA) offer pronounced nematocidal activity against B. xylophilus [17]. Interestingly, B. xylophilus can express numerous lectin proteins by itself [18]. This factor raises the following question: Do these endogenous lectin proteins from B. xylophilus exhibit nematocidal activity against itself? To date, no study has investigated the nematocidal potential of endogenous lectins in B. xylophilus.
We hypothesize that the overexpression of endogenous lectins from B. xylophilus could also bind to receptor proteins in the nematode’s intestinal tract, ultimately leading to the organism’s death. To verify this hypothesis, this study identified and synthesized endogenous lectins based on a genomic database of B. xylophilus to test their binding ability to the intestinal epithelial membrane and their toxicity against B. xylophilus. This study also investigated the nematocidal mechanism of lectins, providing fundamental insights into controlling B. xylophilus.

2. Materials and Methods

2.1. Culture of Pinewood Nematode and Bacterial Strain

The pinewood nematode and Pestalotiopsis spp. were provided by the Institute of Forest Protection, Fujian Agriculture and Forestry University. First, the Pestalotiopsis spp. were cultured on potato dextrose agar (PDA) plates and incubated at 28 °C with 80% relative humidity (RH) until the fungus fully colonized the entire plate. Then, the pinewood nematode was introduced onto these fungal mats and maintained under the same conditions (28 °C, 80% RH), using the pre-grown Pestalotiopsis spp. as its food source. Fourth-stage juvenile nematodes (JIVs) were obtained 4–5 days after introducing the organisms [19]. Before the bioassay tests, fresh JIVs were collected using a Baermann funnel and then washed 3–4 times with sterile water [20]. Escherichia coli strains and plasmids are listed in Supplemental Table S1. All E. coli strains were grown in a Luria–Bertani (LB) liquid medium supplemented with ampicillin (100 μg/mL) and incubated at 37 °C.

2.2. Screening of Genomic Data and Prediction of Conserved Domains

We collected the lectin genes and protein sequences of B. xylophilus from NCBI (available online: https://www.ncbi.nlm.nih.gov/ (accessed on 18 July 2024).) and WormBase (available online: https://www.wormbase.org/ (accessed on 18 July 2024).), including galectins, L-type lectins (LTLs), and chitin-binding domains (CBDs). Homology analyses of these lectin proteins were performed using the NCBI protein–protein BLAST 1.4.0 (available online: https://blast.ncbi.nlm.nih.gov/Blast.cgi (accessed on 25 May 2025).). Conserved domain analyses of these lectin proteins were carried out with NCBI-CDD tools (available online: https://www.ncbi.nlm.nih.gov/cdd (accessed on 25 May 2025).).

2.3. Phylogenetic Analysis

A phylogenetic tree was constructed with the IQ-TREE Online Web Service (available online: https://iqtree.github.io (accessed on 26 May 2025).) website using maximum likelihood (ML) with 1000 bootstraps after multiple sequence alignment executed using ClustalW [21,22]. The iTOL was used to display the phylogenetic tree [23].

2.4. Synthesizing, Expression, and Labeling of Lectin from B. xylophilus

Lectin genes (galectins, LTLs, CBDs) were synthesized by Wuhan GeneCreate Biological Engineering Co., Ltd. (Wuhan, China) and cloned into the pGEX-KG vectors. All synthesized plasmids were sequenced to confirm the correct insertion. The galectins and LTL plasmids were transformed into BL21 E. coli strains (DE3), and the CBD plasmids were transformed into Rosetta E. coli strains (DE3). Lectin proteins were expressed and purified with the glutathione-S-transferase (GST)-tag, as previously described, with minor modifications [7,8]. Transformed bacteria were cultured in an LB medium with ampicillin (100 µg/mL) and 0.05 mM IPTG (isopropyl-β-D-galactopyranoside) at 16 °C for 24 h. Proteins were purified using the ProteinIso GST resin protocol (TRAN, Beijing, China). Adding 1% Triton-X-100 during cell disruption significantly increased CBD protein expression. The GST and Cry13Aa1 proteins (stored in the lab) were expressed using the same method. Purified proteins were then biotinylated using EZ-Link™ NHS-Biotin (Pierce20217, Thermo Fisher Scientific, Waltham, MA, USA) and analyzed in 12% SDS-PAGE. The protein concentrations were analyzed using a Bradford reagent (Beyotime, Shanghai, China).

2.5. GPI-Anchored Protein Extraction from B. xylophilus

GPI-anchored proteins were prepared using the fractionation method [24] from a mixture of different instar nematodes. Over 20,000 nematodes were homogenized in a tissue grinder in 100 µL chilled sterile water. Then, 900 µL chilled TBS buffer (10 mM Tris, 150 mM NaCl, 1% Triton X-114, PH 7.4) was added to the homogenate, kept on ice for 1 h, and spun at 10,000× g for 15 min at low temperature. The pellet was discarded, and the supernatant was placed in a 37 °C warm bath for 15 min to induce the solution’s stratification, followed by spinning at 3000× g for 10 min. The upper aqueous phase was then discarded, and the lower detergent phase (a mixture of Triton X-114 and GPI-anchored proteins) was resuspended in 1 mL PBS buffer (2.7 mM KCl, 140 mM NaCl, 1.8 mM KH2PO4, 10 mM Na2HPO4, PH 7.3) and spun at 3000× g for 10 min, repeating the process three times. Then, the detergent phase was mixed with 900 µL chilled acetone, incubated on ice for 40 min, and spun at 10,000× g for 30 min. The supernatant was discarded, and the pellet comprised of GPI-anchored protein was resuspended in 200 µL PBS buffer and stored at −80 °C until use. The protein concentrations of GPI-anchored proteins were analyzed using a Bradford reagent (Beyotime, Shanghai, China).

2.6. Enzyme-Linked Immunosorbent Assay (ELISA)

The binding affinity of lectin proteins to GPI-anchored proteins was determined by ELISA, as described previously, with minor modifications [25]. ELISA plates (96-well, JET BIOFIL, Guangzhou, China) were incubated overnight at 4 °C with 20 µg GPI-anchored proteins per well in a 100 µL coating buffer (50 mM NaHCO3, PH 9.6), followed by three washes with a PBST buffer (8 mM Na2HPO4, 0.136 mM NaCl, 2 mM KH2PO4, 2.6 mM KCl, 0.05% Tween-20). The plates were then incubated with PBS/0.1% Tween-20/0.5% gelatin for 2 h at 37 °C and washed three times with a PBST buffer. Biotinylated lectins or GST proteins (0, 40, 80, 160, and 320 nM) in PBST were transferred to the coated plates, placed for 2 h at 37 °C, and washed again with PBST. The lectins or GST proteins bound to the GPI-anchored proteins were detected with an anti-streptavidin-HRP antibody (Bioss, Beijing, China) (1:3000 dilutions) for 2 h at 37 °C. HRP enzymatic activity was revealed with the TMB solution (Beyotime, Shanghai, China) under dark conditions for 15 min at room temperature. The enzymatic reaction was then stopped with 2 M H2S04 and the absorbance read at 450 nm with a microplate reader (Multiskan™ FC, Thermo Fisher Scientific, Waltham, MA, USA). Each treatment was repeated three times, and the data were analyzed using GraphPad Prism v.9 software.

2.7. Toxicity Analysis

Nematode bioassays were conducted in a 96-well plate (Corning, New York, NY, USA) with sterile water at 28 °C. Synchronized JIVs were added to 96-well plates with lectin proteins at different concentrations (150, 100, 50, 25, and 10 µg/mL) according to the reported method [8]. Each well was filled with 90 µL of sterile water containing a nematode suspension (approximately 40 nematodes), after which 10 µL of lectin protein was added and mixed well. The negative control group was treated with 10 µL of sterile water, and the positive control group was treated with 10 µL of Cry13Aa1 protein. Each test was repeated three times. The mortality rates of the nematodes were analyzed after ingesting each lectin protein at 48 h.

2.8. Statistical Analysis

Bar graphs were generated using GraphPad Prism software version 9. Beta regression analysis was performed on the percentage mortality data of nematodes caused by different toxins at 150 µg/mL concentration using the betareg package in R. The LC50 of toxins was calculated using probit analysis in GraphPad Prism software version 9. Following Tukey’s post hoc test, significant differences at p < 0.05 were indicated by letters a-m.

3. Results

3.1. Characterization of B. xylophilus Lectin Genes

Through screening and analysis of the B. xylophilus genome data, we identified 25 nematode lectin genes (i.e., 21 Bxgalectins, 1 BxLTL, and 3 BxCBDs) (Figure 1). To determine the phylogenetic relationship of Bxgalectins with homologous galectins, galectins from the 14 nematodes species were obtained from NCBI, and a phylogenetic tree was generated. The results revealed that Bxgalectin10 and Bxgalectin3 from B. xylophilus were closely clustered with the B. okinawaensis Kanzaki, Tanaka, Giblin-Davis and Davies, 2008 (Tylenchida: Aphelenchoididae) galectin, Bxgalectin8 from B. xylophilus was closely clustered with the Ditylenchus destructor Thorne, 1945 (Tylenchida: Anguinidae) galectin, and Bxgalectin4 from B. xylophilus was closely clustered with the Trichostrongylus colubriformis (Giles, 1892) (Strongylida: Trichostrongylidae) galectin (Figure 1A). Bxgalectin2–9, 17, and 18 contained a single GLECT domain, while Bxgalectin10, 11, 14, 15, 16, 19, and 20 consisted of a GLECT superfamily domain. Bxgalectin1 and Bxgalectin13 contained the Gal-bind lectin domain, a GLECT domain homolog. However, Bxgalectin21 consisted of the Gal Rha Lectin superfamily (Figure 1A). The B. xylophilus lectin gene BxLTL1 containing a single L-type superfamily domain showed approximately 99.9% identity with B. okinawaensis (Figure 1B). BxCBD1, BxCBD2, and BxCBD3 contained the ChtBD2 and CBM14 domains (Figure 1C). Among them, BxCBD1 and BxCBD2 were on a single branch, which was clustered with Trichinella pseudospiralis Garkavi, 1972 (Trichocephalida: Trichinellidae), B. okinawaensis, and BxCBD3, unlike the CBDs from other nematodes (Figure 1C).

3.2. Synthesis of B. xylophilus Lectin Genes

The 21 Bxgalectin, 3 BxCBD, and 1 BxLTL genes were successfully synthesized and cloned into the protein expression vector pGEX-KG (Figure 2A) (Figure 2C, lane 1–3; Figure 2D, lane 2). The recombinant plasmids of the Bxgalectin and BxCBD genes were digested using the BamHI and XhoI (or XbaI and SalI) restriction endonuclease (Figure 2B,C, lane 4–6), and the recombinant plasmid of BxLTL1 was digested via the BamHI and SacI restriction endonuclease (Figure 2D, lane1). The target fragments of recombinant plasmids from the Bxgalectin, BxCBD, and BxLTL genes are referred to in Supplemental Table S1.

3.3. Expression of Cry13Aa1, GST, and B. xylophilus Lectin Proteins

The Cry13Aa1 and GST proteins were expressed and purified, showing a 116 kDa (combined with a GST tag) and a 26 kDa individual band in SDS-PAGE (Figure 3). With the addition of a GST tag, the purified Bxgalectin proteins showed an increased molecular weight of 35–42 kDa (see Supplemental Table S1) (Figure 3)). The purified BxCBD1, BxCBD2, BxCBD3, and BxLTL1 proteins had molecular weights of 55 kDa, 60 kDa, 57 kDa, and 54 kDa, respectively (Figure 3). The band size of the BxLTL1 protein is small because this protein easily degrades during expression.

3.4. Toxicity Determination of Nematodes Treated with Lectin Proteins

Mortality in synchronized JIVs exposed to 150 µg/mL Cry13Aa1 or lectin proteins was measured at 48 h. In bioassays of nematodes treated with Cry13Aa1 protein (positive control), nematode mortality reached 65.8%. A mortality rate of over 50% was observed in nematodes exposed to Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, and BxLTL1 (Figure 4). Bxgalectin3 and Bxgalectin4 showed a higher nematode mortality rate than Cry13Aa1, with Bxgalectin4 having the highest mortality (88%) for B. xylophilus (Figure 4).
Subsequently, bioassays with gradient concentrations (10, 25, 50, 100, 150 µg/mL) were conducted on the effective nematocidal proteins Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, BxLTL1, and Cry13Aa1. The results demonstrated LC50 values of 70.71, 91.05, 61.63, 34.12, 135.5, and 166.2 µg/mL for Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, BxLTL1, and Cry13Aa1, respectively (Table 1).

3.5. Binding Affinity of Lectin Proteins with GPI-Anchored Proteins

For proteins Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, and BxLTL1 with nematode mortality rates exceeding 50%, ELISA binding assays were performed to obtain their relative binding affinity to GPI-anchored proteins of B. xylophilus. The proteins Bxgalectin11, which has a low mortality rate, and Cry13Aa1 were used as a control. The results revealed that the binding affinity of Bxgalectin3 (Kd = 8.992 nM) (Figure 5B) and Bxgalectin4 (Kd = 9.634 nM) (Figure 5C) fusion proteins to GPI-anchored proteins via one-site binding was higher than that of Cry13Aa (Kd = 15.38 nM) (Figure 5G), whereas a negligible amount of the control GST protein bound to GPI-anchored proteins. Bxgalectin2 (Kd = 16.50 nM), Bxgalectin9 (Kd = 16.48 nM), and BxLTL1 (Kd = 24.34 nM) had a lower affinity than Cry13Aa for GPI-anchored proteins of B. xylophilus (Figure 5A, D and F). However, Bxgalectin11, which offers lower nematocidal activity, is rarely bound to GPI-anchored proteins (Figure 5E).

4. Discussion

Current research suggests that lectins within the phylum Nematoda can be classified into C-type lectins, galectins, calnexin/calreticulin, legume lectins (L-type lectins in animals, LTLs), ricin-B-type lectins, Hevein-like domains, M-type lectins, LysM domains, F-type lectins, and chitinase-like lectins [18]. Our previous research found that endogenous lectins from B. xylophilus can be classified into C-type lectins, galectins, LTLs, and CBDs. However, C-type lectins are mainly involved in insects’ immune responses, while galectins, LTLs, and CBDs can directly act as insecticidal toxins to poison insects or inhibit insect development [6,26,27,28]. Therefore, this study focused on the galectins, LTLs, and CBDs from B. xylophilus to study their nematocidal activity. We identified twenty one Bxgalectins, one BxLTL, and three BxCBDs in the genome of B. xylophilus. Among these, Bxgalectins primarily consisted of GLECT domains, GLECT superfamily domains, or Gal-bind lectin domains. BxLTL1 contained a single L-type superfamily domain, while BxCBD1, BxCBD2, and BxCBD3 harbored ChtBD2 and CBM14 domains. The structural features of these lectins were similar to those reported in previous studies [18]. These distinct structures enable the lectins to bind to various glycans, thereby mediating their biological functions [29].
Galectins, which specifically recognize β-galactosides, are not only involved in diverse physiological processes in insects, including growth regulation, developmental control, and immune modulation, but also function as insecticidal proteins for agricultural pest management [30,31,32,33]. For instance, galectin-1, one of the earliest identified members of the galectin family, exists as a homodimer. Chen et al. demonstrated that exposure to galectin-1 at concentrations of 100 µg/mL and 200 µg/mL resulted in 50% mortality of Plutella xylostella Linnaeus, killing 1758 (Lepidoptera: Plutellidae) larvae within 7 and 9 days, respectively [34]. In this study, we observed that Bxgalectin2, Bxgalectin3, Bxgalectin4, and Bxgalectin9 induced over 50% mortality in B. xylophilus within 48 h at a concentration of 150 µg/mL, with Bxgalectin4 exhibiting exceptional efficacy (88% mortality). Compared to previous studies, Bxgalectins demonstrated significantly stronger nematocidal activity against B. xylophilus.
LTLs are among the most widely studied lectins that bind to sugars such as glucose, mannose, and galactose [35]. Studies have shown that lectins combined with mannose or glucose have excellent application prospects in insect inhibition [36]. Sprawka et al. determined that phytohemagglutinin (PHA) is toxic to Sitobion avenae (Fabricius) (Hemiptera: Aphididae) (LC50 > 500 µg/mL) [37]. Zhou et al. found that applying soybean lectin protein to wheat leaves caused 50% mortality of S. avenae after one week [38]. The present study found that more than 50% of B. xylophilus fed with the BxTLT1 concentration (150 µg/mL) died within 48 h. This result indicated that BxTLT1 offers more vigorous insecticidal activity than the leguminous lectin described above.
The discovery of these novel endogenous lectins with high nematocidal activity against B. xylophilus expands the repertoire of toxins targeting this pest. However, given the protracted growth cycles of trees, the implementation of transgenic tree technology expressing toxin genes faces significant challenges [39]. Paratransgenesis—a genetic engineering approach that modifies symbiotic microorganisms to express toxins within a host organism—serves as a viable alternative [40]. This strategy has been successful in pest control. For instance, Wang et al. significantly suppressed malaria transmission by introducing antimalarial toxin genes into mosquito gut symbiotic bacteria, while Hurwitz et al. effectively controlled American trypanosomiasis by engineering Trypanosoma cruzi Chagas, 1909 (Kinetoplastida: Trypanosomatidae) symbiotic bacteria to express toxins [41,42]. Notably, diverse symbiotic bacteria of B xylophilus have been characterized, such as Pseudomonas, Serratia, and Achromobacter [43,44]. Building on this foundation, future efforts could engineer these nematode-associated symbiotic bacteria to express these highly nematocidal lectins—Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, and BxLTL1. This represents a clear innovation: leveraging the nematode’s own symbionts to deliver host-derived toxins creates a targeted biological Trojan horse mechanism. Nevertheless, deployment in forest ecosystems requires careful consideration of potential challenges: (1) the environmental persistence of engineered bacteria, (2) horizontal gene transfer risks to non-target soil microbiota, and (3) possible ecological cascades from perturbing nematode–bacterial mutualisms. Despite these considerations, this paratransgenic approach offers a promising pathway toward ecologically sustainable pine wilt disease management due to its precision, rapid deployability, and circumvention of tree genetic modification hurdles.
The nematocidal mechanisms of lectins essentially involve the specific recognition of and binding to key glycoconjugates (e.g., chitin, glycolipids, and glycoproteins) in the nematode intestine, leading to structural disruption of the gut tissue and, ultimately, resulting in nematode mortality [28]. Consequently, this study employed ELISA to quantify the binding affinity between nematocidal lectins and the GPI-anchored proteins of B xylophilus. The results showed that highly nematocidal lectins—Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, and BxLTL1—displayed strong binding affinities towards the receptors, with Kd values of 6.50 nM, 8.99 nM, 9.63 nM, 16.48 nM, and 24.34 nM, respectively. These findings align with the results of prior studies. Ohizumi et al. found that Dioscorea batatas Decne. (Dioscoreales: Dioscoreaceae) lectin inhibited the development of Helicoverpa armigera (Hübner, 1808) (Lepidoptera: Noctuidae) larvae into adults by strongly binding to the larval brush border [45]. Majumder et al. found that Arum maculatum L. (Alismatales: Araceae) tuber lectin had insecticidal activity against Lipaphis erysimi (Kaltenbach, 1843) (Hemiptera: Aphididae) and Aphis craccivora Koch, 1854 (Hemiptera: Aphididae) by binding to the insects’ gut receptors [46]. Lagarda-Diaz et al. found that plant lectins bind to midgut glycoconjugates, affecting oviposition and adult development in Zabrotes subfasciatus (Boheman, 1833) (Coleoptera: Chrysomelidae) [47].

5. Conclusions

This study is the first to clarify the toxicity of endogenous lectins from B. xylophilus and provide basic data on the interaction between lectins and receptors in the nematode gut. However, the binding mechanisms of these lectins to receptors still require further investigation. Overall, the results of this study provide a direction for the future biological control of B. xylophilus using lectins.

Supplementary Materials

The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/f16071177/s1: Table S1: Bursaphelenchus xylophilus lectin genes in Escherichia coli strains and size of their target fragments and proteins.

Author Contributions

Conceptualization, S.W. and Y.G.; data curation, Y.S., X.L., and W.Y.; formal analysis, S.W. and Y.S.; investigation, Y.S., Z.L., X.L. and W.Y.; methodology, S.W., Y.S. and Y.G.; writing—original draft, S.W., Y.S. and Y.G.; writing—review and editing, S.W., Y.S., Z.L., X.L. and Y.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Natural Science Foundation of China [grant numbers 32171805 and 32401582]; the Natural Science Foundation of Fujian Province, China [grant number 2024J08036]; the Project of Fujian Provincial Forestry Department [grant number 2024FKJ11]; and the Science and Technology Plan Project of Guizhou Province, China [grant number [2024]083].

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Pan, S.J. Research progress in biological control of pine wilt disease. J. Anhui Univ. Nat. Sci. 2023, 47, 92–99. [Google Scholar]
  2. Zhang, X.; Zhao, J.J.; Yan, J.; Fang, G.F.; Huang, J. Economic loss assessment of pine wilt disease in mainland China in 2017. J. Beijing For. Univ. 2020, 42, 96–106. [Google Scholar] [CrossRef]
  3. Takasu, F. A Mathematical Modeling of the Effect of Asymptomatic Carrier Trees on the Spread of the Pine Wilt Disease. J. Jpn. For. Soc. 2019, 101, 30–34. [Google Scholar] [CrossRef]
  4. Han, X.H.; Huang, C.Y.; Qi, H.; Zhu, Y.K.; Hu, X.; Wen, Y.; Long, Y.; Xu, L.; Zhang, F. The construction and evaluation of secretory expression engineering bacteria for the trans-Cry3Aa-T-HasA fusion protein against the Monochamus alternatus vector. Front. Cell. Infect. Microbiol. 2024, 14, 1362961. [Google Scholar] [CrossRef] [PubMed]
  5. Xu, C.X.; Jin, J.F.; Shen, C.; Zhu, Q.; Zhang, X.; Liu, Y.; Liu, X. Research progress of protein-type biological materials with insecticidal function. Chin. J. Pestic. Sci. 2023, 25, 990–1003. [Google Scholar] [CrossRef]
  6. Lagarda-Diaz, I.; Guzman-Partida, A.M.; Vazquez-Moreno, L. Legume Lectins: Proteins with Diverse Applications. Int. J. Mol. Sci. 2017, 18, 1242. [Google Scholar] [CrossRef]
  7. Guo, Y.J.; Huang, L.L.; Zhang, H.; Li, J.; Zhou, Y.Y.; Sun, Y.Z.; Weng, M.Q.; Wu, S.Q.; Lian, C.L. Identification of a Snf7-domain-containing protein that exhibits high affinity and synergistic activity for Cry13Aa1 toxin in Bursaphelenchus xylophilus. J. Invertebr. Pathol. 2025, 210, 108279. [Google Scholar] [CrossRef]
  8. Guo, Y.J.; Weng, M.Q.; Sun, Y.Z.; Carballar-Lejarazú, R.; Wu, S.; Lian, C. Bacillus thuringiensis toxins with nematocidal activity against the pinewood nematode Bursaphelenchus xylophilus. J. Invertebr. Pathol. 2022, 189, 107726. [Google Scholar] [CrossRef]
  9. Guo, Y.J.; Zhou, Y.Y.; Li, J.; Weng, M.Q.; Sun, Y.Z.; Wu, S.Q.; Lian, C.L. Identification of an α-galactosidase with high affinity and synergistic activity against Bacillus thuringiensis App6Aa2 toxin in Bursaphelenchus xylophilus. Pestic. Biochem. Physiol. 2025, 208, 106282. [Google Scholar] [CrossRef]
  10. Hamid, R.; Masood, A.; Wani, I.H.; Rafiq, S. Lectins: Proteins with Diverse Applications. J. Appl. Pharm. Sci. 2013, 3, S93–S103. [Google Scholar] [CrossRef]
  11. Wang, L.J.; Wang, C.; Li, H.; Yang, X.; Wang, Y.; Guo, X.; Xu, B. Isolation of AccGalectin1 from Apis Cerana Cerana and Its Functions in Development and Adverse Stress Response. J. Cell. Biochem. 2019, 120, 671–684. [Google Scholar] [CrossRef]
  12. Macedo, M.L.R.; das Graças Machado Freire, M.; da Silva, M.B.R.; Coelho, L.C.B.B. Insecticidal action of Bauhinia monandra leaf lectin (BmoLL) against Anagasta kuehniella (Lepidoptera: Pyralidae), Zabrotes subfasciatus and Callosobruchus maculatus (Coleoptera: Bruchidae). Comp. Biochem. Physiol. Part A Mol. Integr. Physiol. 2006, 146, 486–498. [Google Scholar] [CrossRef]
  13. Oliveira, C.F.R.D.; Moura, M.C.D.; Napoleão, T.H.; Paiva, P.M.G.; Coelho, L.C.B.B.; Macedo, M.L.R. A chitin-binding lectin from Moringa oleifera seeds (WSMoL) impairs the digestive physiology of the Mediterranean flour larvae, Anagasta kuehniella. Pestic. Biochem. Physiol. 2017, 142, 67–76. [Google Scholar] [CrossRef]
  14. Heim, C.; Hertzberg, H.; Butschi, A.; Bleuler-Martinez, S.; Aebi, M.; Deplazes, P.; Künzler, M.; Štefanić, S. Inhibition of Haemonchus Contortus Larval Development by Fungal Lectins. Parasites Vectors 2015, 8, 425. [Google Scholar] [CrossRef]
  15. Moradi, A.; Austerlitz, T.; Dahlin, P.; Robert, C.A.; Maurer, C.; Steinauer, K.; van Doan, C.; Himmighofen, P.A.; Wieczorek, K.; Künzler, M.; et al. Marasmius oreades agglutinin enhances resistance of Arabidopsis against plant-parasitic nematodes and a herbivorous insect. BMC Plant Biol. 2021, 21, 402. [Google Scholar] [CrossRef]
  16. Moradi, A.; El-Shetehy, M.; Gamir, J.; Austerlitz, T.; Dahlin, P.; Wieczorek, K.; Künzler, M.; Mauch, F. Expression of a Fungal Lectin in Arabidopsis Enhances Plant Growth and Resistance Toward Microbial Pathogens and a Plant-Parasitic Nematode. Front. Plant Sci. 2021, 12, 657451. [Google Scholar] [CrossRef] [PubMed]
  17. Qi, G.F.; Mao, S.Q.; Zhu, F.Y.; Yu, Z.N.; Zhao, X.Y. In vitro assessment of plant lectins with anti-pinwood nematode activity. J. Invertebr. Pathol. 2007, 98, 40–45. [Google Scholar] [CrossRef]
  18. Bauters, L.; Naalden, D.; Gheysen, G. The Distribution of Lectins across the Phylum Nematoda: A Genome-Wide Search. Int. J. Mol. Sci. 2017, 18, 91. [Google Scholar] [CrossRef] [PubMed]
  19. Aikawa, T.; Togashi, K. An Effect of Inoculum Quantity of Bursaphelenchus Xylophilus (nematoda: Aphelenchoididae) on the Nematode Load of Monochamus Alternatus (coleoptera: Cerambycidae) in Laboratory. Jpn. J. Nematol. 1997, 27, 14–21. [Google Scholar] [CrossRef]
  20. Cesarz, S.; Eva Schulz, A.; Beugnon, R.; Eisenhauer, N. Testing soil nematode extraction efficiency using different variations of the Baermann-funnel method. Soil Org. 2019, 91, 61–72. [Google Scholar] [CrossRef]
  21. Trifinopoulos, J.; Nguyen, L.-T.; von Haeseler, A.; Minh, B.Q. W-IQ-TREE: A fast online phylogenetic tool for maximum likelihood analysis. Nucleic Acids Res. 2016, 44, W232–W235. [Google Scholar] [CrossRef]
  22. Tamura, K.; Peterson, D.; Peterson, N.; Stecher, G.; Nei, M.; Kumar, S. MEGA5: Molecular Evolutionary Genetics Analysis Using Maximum Likelihood, Evolutionary Distance, and Maximum Parsimony Methods. Mol. Biol. Evol. 2011, 28, 2731–2739. [Google Scholar] [CrossRef]
  23. Letunic, I.; Bork, P. Interactive Tree of Life (iTOL) v6: Recent updates to the phylogenetic tree display and annotation tool. Nucleic Acids Res. 2024, 52, W78–W82. [Google Scholar] [CrossRef] [PubMed]
  24. Hooper, N.M. Identification of a glycosyl phosphatidylinositol anchor on membrane proteins. In Lipid Modification of Proteins: A Practical Approach; Hooper, N.M., Turner, A.J., Eds.; Oxford University Press: Oxford, UK, 1992; pp. 89–116. [Google Scholar]
  25. Batool, K.; Alam, I.; Jin, L.; Xu, J.; Wu, C.X.; Wang, J.X.; Huang, E.; Guan, X.; Yu, X.Q.; Zhang, L.L. CTLGA9 Interacts with ALP1 and APN Receptors To Modulate Cry11Aa Toxicity in Aedes aegypti. J. Agric. Food Chem. 2019, 67, 8896–8904. [Google Scholar] [CrossRef] [PubMed]
  26. Chen, C.S.; Chen, C.Y.; Ravinath, D.M.; Bungahot, A.; Cheng, C.P.; You, R.I. Functional characterization of chitin-binding lectin from Solanum integrifolium containing anti-fungal and insecticidal activities. BMC Plant Biol. 2018, 18, 3. [Google Scholar] [CrossRef] [PubMed]
  27. Xia, X.f.; You, M.s.; Rao, X.J.; Yu, X.Q. Insect C-type Lectins in Innate Immunity. Dev. Comp. Immunol. 2018, 83, 70–79. [Google Scholar] [CrossRef]
  28. Takeuchi, T.; Tamura, M.; Ishiwata, K.; Hamasaki, M.; Hamano, S.; Arata, Y.; Hatanaka, T. Galectin-2 suppresses nematode development by binding to the invertebrate-specific galactoseβ1-4fucose glyco-epitope. Glycobiology 2019, 29, 504–512. [Google Scholar] [CrossRef]
  29. Theopold, U.; Rissler, M.; Fabbri, M.; Schmidt, O.; Natori, S. Insect glycobiology: A lectin multigene family in Drosophila melanogaster. Biochem. Biophys. Res. Commun. 1999, 261, 923–927. [Google Scholar] [CrossRef]
  30. Hao, L.; Wu, K.; Chen, X.G.; Wang, Q. Cloning, prokaryotic expression and immunoreactivity evaluation of Angiostrongylus cantonensis galectin. J. S. Med. Univ. 2007, 27, 584–587. Available online: https://www.j-smu.com/CN/Y2007/V27/I05/584 (accessed on 7 June 2025).
  31. Kim, J.Y.; Cho, M.K.; Choi, S.H.; Lee, K.H.; Ahn, S.C.; Kim, D.-H.; Yu, H.S. Inhibition of dextran sulfate sodium (DSS)-induced intestinal inflammation via enhanced IL-10 and TGF-β production by galectin-9 homologues isolated from intestinal parasites. Mol. Biochem. Parasitol. 2010, 174, 53–61. [Google Scholar] [CrossRef]
  32. Wang, J.; Yan, R.F.; Xu, L.X.; Li, X. The second glutamic acid in the C-terminal CRD affects the carbohydrate-binding properties of recombinant galectins of Haemonchus contortus. Vet. Parasitol. 2007, 148, 247–255. [Google Scholar] [CrossRef]
  33. Young, A.R.; Meeusen, E.N. Galectins in parasite infection and allergic inflammation. Glycoconj. J. 2004, 19, 601–606. [Google Scholar] [CrossRef]
  34. Chen, S.J.; Chen, N.T.; Wang, S.H.; Hsu, J.C.; Ding, W.-H.; Kuo-Huang, L.-L.; Huang, R.N. Insecticidal action of mammalian galectin-1 against diamondback moth (Plutella xylostella). Pest Manag. Sci. 2009, 65, 923–930. [Google Scholar] [CrossRef]
  35. Taylor, M.E.; Drickamer, K. Convergent and divergent mechanisms of sugar recognition across kingdoms. Curr. Opin. Struct. Biol. 2014, 28, 14–22. [Google Scholar] [CrossRef]
  36. Katoch, R.; Tripathi, A. Research advances and prospects of legume lectins. J. Biosci. 2021, 46, 104. [Google Scholar] [CrossRef] [PubMed]
  37. Sprawka, I.; Goławska, S.; Czerniewicz, P.; Sytykiewicz, H. Insecticidal action of phytohemagglutinin (PHA) against the grain aphid, Sitobion avenae. Pestic. Biochem. Physiol. 2011, 100, 64–69. [Google Scholar] [CrossRef]
  38. Zhou, Y.; Xie, H.W.; Liu, C.A.; Kuang, Q.; Pan, J.T.; Chen, Q.S.; Xu, W.B.; Yu, C.; Peng, X.Y. Cloning of Lectin Le4 Gene from Leguminosae and the Aphid Resistance Effect of Its Protein Production. Genom. Appl. Biol. 2016, 35, 3474–3480. [Google Scholar] [CrossRef]
  39. Yin, Y.Y.; Wang, C.; Xiao, D.D.; Liang, Y.; Wang, Y. Advances and Perspectives of Transgenic Technology and Biotechnological Application in Forest Trees. Front. Plant Sci. 2021, 12, 786328. [Google Scholar] [CrossRef]
  40. Cui, C.L.; Chen, J.J.; Wang, S.B. Genetic control and paratransgenesis of mosquito-borne diseases. Chin. J. Appl. Entomol. 2015, 52, 1061–1071. [Google Scholar] [CrossRef]
  41. Wang, S.B.; Dos-Santos, A.L.A.; Huang, W.; Liu, K.C.; Oshaghi, M.A.; Wei, G.; Agre, P.; Jacobs-Lorena, M. Driving mosquito refractoriness to Plasmodium falciparum with engineered symbiotic bacteria. Science 2017, 357, 1399–1402. [Google Scholar] [CrossRef]
  42. Hurwitz, I.; Fieck, A.; Read, A.; Hillesland, H.; Klein, N.; Kang, A.; Durvasula, R. Paratransgenic control of vector borne diseases. Int. J. Biol. Sci. 2011, 7, 1334–1344. [Google Scholar] [CrossRef]
  43. Proença, D.N.; Grass, G.; Morais, P.V. Understanding pine wilt disease: Roles of the pine endophytic bacteria and of the bacteria carried by the disease-causing pinewood nematode. MicrobiologyOpen 2016, 6, e00415. [Google Scholar] [CrossRef]
  44. Guo, Y.J.; Lin, Q.N.; Chen, L.; Carballar-Lejarazú, R.; Zhang, A.; Shao, E.; Liang, G.; Hu, X.; Wang, R.; Xu, L.; et al. Characterization of bacterial communities associated with the pinewood nematode insect vector Monochamus alternatus Hope and the host tree Pinus massoniana. BMC Genom. 2020, 21, 337. [Google Scholar] [CrossRef]
  45. Ohizumi, Y.; Gaidamashvili, M.; Ohwada, S.; Matsuda, K.; Kominami, J.; Nakamura-Tsuruta, S.; Hirabayashi, J.; Naganuma, T.; Ogawa, T.; Muramoto, K. Mannose-binding lectin from yam (Dioscorea batatas) tubers with insecticidal properties against Helicoverpa armigera (Lepidoptera: Noctuidae). J. Agric. Food Chem. 2009, 57, 2896–2902. [Google Scholar] [CrossRef]
  46. Majumder, P.; Mondal, H.A.; Das, S. Insecticidal activity of Arum maculatum tuber lectin and its binding to the glycosylated insect gut receptors. J. Agric. Food Chem. 2005, 53, 6725–6729. [Google Scholar] [CrossRef]
  47. Lagarda-Diaz, I.; Guzman-Partida, A.M.; Urbano-Hernandez, G.; Ortega-Nieblas, M.M.; Robles-Burgueño, M.R.; Winzerling, J.; Vazquez-Moreno, L. Insecticidal action of PF2 lectin from Olneya tesota (Palo Fierro) against Zabrotes subfasciatus larvae and midgut glycoconjugate binding. J. Agric. Food Chem. 2009, 57, 689–694. [Google Scholar] [CrossRef]
Forests 16 01177 g001
Figure 1. Phylogenetic tree of Bursaphelenchus xylophilus (Steiner & Bührer, 1934) Nickle, 1970 (Nematoda: Parasitaphelenchidae) galectins (A), L-type lectin (LTL) (B), and chitin-binding domains (CBDs) (C) with predicted domains. The phylogenetic tree was constructed using an ML phylogenetic tree model with 1000 bootstraps. Conserved domains of lectin proteins were analyzed using the NCBI-CDD database. The bootstrap values are shown next to the nodes. The numbers preceding each nematode name show the GenBank numbers of the lectin proteins in the NCBI database. The asterisk indicates the lectin genes identified in the present study.
Figure 1. Phylogenetic tree of Bursaphelenchus xylophilus (Steiner & Bührer, 1934) Nickle, 1970 (Nematoda: Parasitaphelenchidae) galectins (A), L-type lectin (LTL) (B), and chitin-binding domains (CBDs) (C) with predicted domains. The phylogenetic tree was constructed using an ML phylogenetic tree model with 1000 bootstraps. Conserved domains of lectin proteins were analyzed using the NCBI-CDD database. The bootstrap values are shown next to the nodes. The numbers preceding each nematode name show the GenBank numbers of the lectin proteins in the NCBI database. The asterisk indicates the lectin genes identified in the present study.
Forests 16 01177 g001
Forests 16 01177 g002
Figure 2. Restriction enzyme digestion of lectin recombinant plasmids. (A) Recombinant plasmids and (B) double-digestion products of Bxgalectin1 to 21 (A). Lane M: 5000 bp DNA ladder; lane 1 to 21: recombinant plasmids of Bxgalectin 1 to 21. (B). Lane M: 5000 bp DNA ladder; lane 1–4, 7–18, and lane 20–21: BamHI and XhoI simultaneously digested Bxgalectins plasmid; lane 5, 6, 19: XbaI and SalI simultaneously digested Bxgalectins plasmid). (C) Recombinant plasmids and double-digestion products of BxCBD1, 2, 3 (Lane M: 1Kb DNA ladder; lane 1–3: recombinant plasmids of BxCBD1, 2, 3; lane 4–6: BamHI and XhoI simultaneously-digested BxCBD plasmid). (D) Recombinant plasmids and double-digestion products of BxLTL1 (Lane M: 5000 bp DNA ladder; lane 1: BamHI and SacI simultaneously digested BxLTL1 plasmid, lane 2: recombinant plasmids of BxLTL1).
Figure 2. Restriction enzyme digestion of lectin recombinant plasmids. (A) Recombinant plasmids and (B) double-digestion products of Bxgalectin1 to 21 (A). Lane M: 5000 bp DNA ladder; lane 1 to 21: recombinant plasmids of Bxgalectin 1 to 21. (B). Lane M: 5000 bp DNA ladder; lane 1–4, 7–18, and lane 20–21: BamHI and XhoI simultaneously digested Bxgalectins plasmid; lane 5, 6, 19: XbaI and SalI simultaneously digested Bxgalectins plasmid). (C) Recombinant plasmids and double-digestion products of BxCBD1, 2, 3 (Lane M: 1Kb DNA ladder; lane 1–3: recombinant plasmids of BxCBD1, 2, 3; lane 4–6: BamHI and XhoI simultaneously-digested BxCBD plasmid). (D) Recombinant plasmids and double-digestion products of BxLTL1 (Lane M: 5000 bp DNA ladder; lane 1: BamHI and SacI simultaneously digested BxLTL1 plasmid, lane 2: recombinant plasmids of BxLTL1).
Forests 16 01177 g002
Forests 16 01177 g003
Figure 3. SDS-PAGE gel of Cry13Aa1, GST, and B. xylophilus lectin proteins. Proteins were expressed in an LB medium with different IPTGs at 16 °C for 24 h and purified using the ProteinIso GST Resin protocol.
Figure 3. SDS-PAGE gel of Cry13Aa1, GST, and B. xylophilus lectin proteins. Proteins were expressed in an LB medium with different IPTGs at 16 °C for 24 h and purified using the ProteinIso GST Resin protocol.
Forests 16 01177 g003
Forests 16 01177 g004
Figure 4. Nematode mortality with 150 µg/mL concentrations of lectin proteins or Cry13Aa1 protein diluted with sterile water over 48 h. Among them, Cry13Aa1 was used as the positive control for this test. Each bar represents the mean ± SD of three technical replicates. Statistical significance at p < 0.05 was designated using a–m. Groups sharing the same letter (a–m) are not significantly different (p ≥ 0.05); different letters indicate statistical significance (p < 0.05). The brown bar (square) represents the bioassays of nematodes treated with Cry13Aa1 protein (positive control). The red bars (asterisk) indicate lectin proteins causing >50% nematode mortality.
Figure 4. Nematode mortality with 150 µg/mL concentrations of lectin proteins or Cry13Aa1 protein diluted with sterile water over 48 h. Among them, Cry13Aa1 was used as the positive control for this test. Each bar represents the mean ± SD of three technical replicates. Statistical significance at p < 0.05 was designated using a–m. Groups sharing the same letter (a–m) are not significantly different (p ≥ 0.05); different letters indicate statistical significance (p < 0.05). The brown bar (square) represents the bioassays of nematodes treated with Cry13Aa1 protein (positive control). The red bars (asterisk) indicate lectin proteins causing >50% nematode mortality.
Forests 16 01177 g004
Forests 16 01177 g005
Figure 5. Total binding of lectin and Cry13Aa1 proteins to the GPI-anchored proteins of B. xylophilus. ELISA 96-well plates coated with 20 µg GPI-anchored proteins were incubated with increasing concentrations of biotinylated Bxgalectin2-GST (A), Bxgalectin3-GST (B), Bxgalectin4-GST (C), Bxgalectin9-GST (D), Galectin11-GST (E), BxLTL1-GST (F), and Cry13Aa1 (G). Each bar represents the means ± SEM of three technical replicates.
Figure 5. Total binding of lectin and Cry13Aa1 proteins to the GPI-anchored proteins of B. xylophilus. ELISA 96-well plates coated with 20 µg GPI-anchored proteins were incubated with increasing concentrations of biotinylated Bxgalectin2-GST (A), Bxgalectin3-GST (B), Bxgalectin4-GST (C), Bxgalectin9-GST (D), Galectin11-GST (E), BxLTL1-GST (F), and Cry13Aa1 (G). Each bar represents the means ± SEM of three technical replicates.
Forests 16 01177 g005
Table 1. Nematocidal activity of different protoxins against B. xylophilus.
Table 1. Nematocidal activity of different protoxins against B. xylophilus.
Toxin A 1LC50 (µg/mL) (±SD) 295% Confidence IntervalSlope
Cry13Aa170.71 (±10.54) ab53.79–96.630.8825
Bxgalectin291.05 (±40.22) ab66.13–142.70.7649
Bxgalectin361.63 (±7.91) ab51.02–74.431.324
Bxgalectin434.12 (±5.34) b24.75–45.461.089
Bxgalectin9135.5 (±12.88) ab112.2–175.50.9332
BxLTL1166.2 (±51.06) a123.2–313.31.033
1 JIVs were used in the bioassays. There were three replications per treatment, with 40 larvae per replication. 2 The mean lethal concentration (LC50) was estimated via probit analysis. Different lowercase letters indicate a significant difference at p < 0.05.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Wu, S.; Sun, Y.; Li, Z.; Li, X.; Yu, W.; Guo, Y. Nematocidal Activity and Intestinal Receptor-Binding Affinity of Endogenous Lectins in Bursaphelenchus xylophilus (Pinewood Nematode). Forests 2025, 16, 1177. https://doi.org/10.3390/f16071177

AMA Style

Wu S, Sun Y, Li Z, Li X, Yu W, Guo Y. Nematocidal Activity and Intestinal Receptor-Binding Affinity of Endogenous Lectins in Bursaphelenchus xylophilus (Pinewood Nematode). Forests. 2025; 16(7):1177. https://doi.org/10.3390/f16071177

Chicago/Turabian Style

Wu, Songqing, Yunzhu Sun, Zibo Li, Xinquan Li, Wei Yu, and Yajie Guo. 2025. "Nematocidal Activity and Intestinal Receptor-Binding Affinity of Endogenous Lectins in Bursaphelenchus xylophilus (Pinewood Nematode)" Forests 16, no. 7: 1177. https://doi.org/10.3390/f16071177

APA Style

Wu, S., Sun, Y., Li, Z., Li, X., Yu, W., & Guo, Y. (2025). Nematocidal Activity and Intestinal Receptor-Binding Affinity of Endogenous Lectins in Bursaphelenchus xylophilus (Pinewood Nematode). Forests, 16(7), 1177. https://doi.org/10.3390/f16071177

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop