scholarly journals Diversity and Distribution of Xylophagous Beetles from Pinus thunbergii Parl. and Pinus massoniana Lamb. Infected by Pine Wood Nematode

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1549
Author(s):  
Xu Chu ◽  
Qiuyu Ma ◽  
Meijiao Yang ◽  
Guoqiang Li ◽  
Jinyan Liu ◽  
...  
Keyword(s):  
Bark Beetles ◽  
Morphological Characteristics ◽  
Pinus Massoniana ◽  
Bursaphelenchus Xylophilus ◽  
Community Diversity ◽  
Pinewood Nematode ◽  
Host Trees ◽  
Pine Trees ◽  
Spatial Niche ◽  
Pinus Massoniana Lamb

The vectors of pinewood nematode of Bursaphelenchus xylophilus (Steiner & Bührer, 1934) are mainly known as xylophagous beetles. Understanding the composition and distribution of these xylophagous beetles in host pine trees infected by PWN is critical to control the spread of PWN. In this study, we investigated the community structures of the xylophagous beetles in two main host trees in Fujian and Shandong, Pinus massoniana Lamb. and Pinus thunbergia Parl., in different stages of infection. All beetles were collected by dissecting the whole pine trees and then identified by their morphological characteristics and COI genes. The results showed that the diversity of xylophagous beetles was different not only between the two host pine trees but also among the different infection stages. The diversity of P. massoniana xylophagous beetles was significantly higher than that of P. thunbergii, and there were also significant differences in the different stages of PWN infection. In total, Scolytinae was the most common (53.70%), followed by Curculionidae (18.26%), Cerambycidae (16.31%), and Cleridae (6.04%). Monochamus alternatus, the most important vector of PWN, occupied a large niche and showed different aggregation positions during the three infection stages in both host trees. This result might be related to the resistance of bark beetles to host trees and competition with other xylophagous beetles. The community diversity of xylophagous beetles was jointly affected by both the infection stages of PWN and the spatial niche of xylophagous beetles. Knowledge of the diversity and competitive relationships among xylophagous beetles might help regulate the population dynamics of these beetles.

Variations of Phyllosphere and Rhizosphere Microbial Communities of Pinus Koraiensis Infected by Bursaphelenchus Xylophilus

2021 ◽  
Author(s):  
Jiaojiao Deng ◽  
Dapao Yu ◽  
Wangming Zhou ◽  
Wenxu Zhu ◽  
Li Zhou
Keyword(s):  
Microbial Community ◽  
Microbial Diversity ◽  
Early Stage ◽  
Bursaphelenchus Xylophilus ◽  
Community Diversity ◽  
Pinus Koraiensis ◽  
Pinewood Nematode ◽  
Rhizosphere Fungi ◽  
Pine Trees ◽  
Rhizosphere Microbial Community

Abstract Pinewood nematode, Bursaphelenchus xylophilus, as one of the greatest threats to pine trees, is spreading all over the world. During the nematode’s pathogenesis, plant microorganisms play important roles.The phyllosphere and rhizosphere bacterial and fungal communities associated with healthy P. koraiensis (PKa) and P. koraiensis infected by B. xylophilus at the early (PKb) and last (PKc) stages were analyzed. Pine wood nematode (PWD) could increase the phyllosphere and rhizosphere microbial community diversity, and slight shifts of the microbial diversity were observed at the early stage of infection. Generally speaking, an increase in microbial diversity with more serious symptomatic phase was obvious and visible. The phyllosphere and rhizosphere microbial community potentially changed caused by B. xylophilus infection of P. koraiensis. With the infection of B. xylophilus in P. koraiensis, Bradyrhizobium (rhizosphere bacteria), Massilia (phyllosphere bacteria), Phaeosphaeriaceae (rhizosphere fungi) were the major contributors to the differences in community compositions among different treatments. With the infection of PWD, most of the bacterial groups tended to be co-excluding rather than co-occurring. These changes would correlate with microbial ability to suppress plant pathogen, enhancing the understanding of disease development and providing guidelines to pave the way for its possible management.

scholarly journals Study of symptoms and gene expression in four Pinus species after pinewood nematode infection

2011 ◽  
Vol 9 (2) ◽  
pp. 272-275 ◽  
Author(s):  
Albina R. Franco ◽  
Carla Santos ◽  
Mariana Roriz ◽  
Rui Rodrigues ◽  
Marta R. M. Lima ◽  
...  
Keyword(s):  
Virulent Strain ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pinewood Nematode ◽  
Pine Trees ◽  
Severe Infections ◽  
Genomic Results ◽  
Avirulent Isolate

Pine wilt disease, caused by the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, is originating severe infections in pine trees. The disease is detected when external symptoms appear (e.g. needle chlorosis), but trees could remain asymptomatic for long periods and serve as a long-term host. The primary goal of this study was to assess the effect of inoculation with an avirulent isolate of B. xylophilus (C14-5) on different Pinus spp. seedlings (P. sylvestris, P. nigra, P. pinea and P. pinaster). At the same time, seedlings were also inoculated with a virulent strain, HF, in order to compare the phenotypic and genomic results of the two types of inoculations. The effect of inoculation was determined in terms of expression of various Pinus genes potentially involved in the response to the disease.The results suggest that P. pinea and P. nigra are more resistant to infection by the nematode than P. sylvestris and P. pinaster. The phenotypic and genetic differences were more marked among P. pinea and P. pinaster.

scholarly journals α-l-Fucosidases from Bursaphelenchus xylophilus Secretome—Molecular Characterization and Their Possible Role in Breaking Down Plant Cell Walls

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 265
Author(s):  
Joana M.S. Cardoso ◽  
Luís Fonseca ◽  
Isabel Abrantes
Keyword(s):  
Cell Wall ◽  
Molecular Characterization ◽  
Three Dimensional ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes ◽  
Host Trees ◽  
Resin Canals

The pinewood nematode (PWN) Bursaphelenchus xylophilus, the causal agent of the pine wilt disease (PWD), enters above-ground parts of the tree, migrates through the resin canals and feeds on plant cells causing extensive damage. In order to penetrate the cell wall and establish a parasitic relationship with host trees, the PWN needs to secretea mixture of active cell wall degrading enzymes. In maritime pine, Pinus pinaster, which is high susceptible to PWN, xyloglucan is the major hemicellulosic polysaccharide in primary cells. The xyloglucan backbone is susceptible to hydrolysis by numerous endoglucanases, some of them specific to xyloglucan. However, to completely degrade xyloglucan, all substitutions on the glucan backbones must be released, and l-fucose residues in xyloglucan branches are released by α-l-fucosidases. In the present study, the molecular characterization of two α-l-fucosidases found in PWN secretome was performed. Moreover, a novel α-l-fucosidase was identified and its cDNA and gene sequence were determined. The three-dimensional structures of these α-l-fucosidases were predicted and the transcript levels were analyzed, thus providing new insights into fundamental PWN biology and the possible role of these proteins as cell wall degrading enzymes.

scholarly journals Comparative Transcriptome Analysis of the Pinewood Nematode Bursaphelenchus xylophilus Reveals the Molecular Mechanism Underlying Its Defense Response to Host-Derived α-pinene

2019 ◽  
Vol 20 (4) ◽  
pp. 911 ◽  
Author(s):  
Yongxia Li ◽  
Fanli Meng ◽  
Xun Deng ◽  
Xuan Wang ◽  
Yuqian Feng ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Bursaphelenchus Xylophilus ◽  
Stress Reaction ◽  
Reproduction Rate ◽  
Molecular Response ◽  
Pinewood Nematode ◽  
Comparative Transcriptome ◽  
Pine Tree ◽  
Pine Trees

Bursaphelenchus xylophilus is fatal to the pine trees around the world. The production of the pine tree secondary metabolite gradually increases in response to a B. xylophilus infestation, via a stress reaction mechanism(s). α-pinene is needed to combat the early stages of B. xylophilus infection and colonization, and to counter its pathogenesis. Therefore, research is needed to characterize the underlying molecular response(s) of B. xylophilus to resist α-pinene. We examined the effects of different concentrations of α-pinene on the mortality and reproduction rate of B. xylophilus in vitro. The molecular response by which B. xylophilus resists α-pinene was examined via comparative transcriptomics of the nematode. Notably, B. xylophilus genes involved in detoxification, transport, and receptor activities were differentially expressed in response to two different concentrations of α-pinene compared with control. Our results contribute to our understanding of the molecular mechanisms by which B. xylophilus responds to monoterpenes in general, and the pathogenesis of B. xylophilus.

Pine chemical volatiles promote dauer recovery of a pine parasitic nematode, Bursaphelenchus xylophilus

Parasitology ◽  
2019 ◽  
Vol 147 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Wei Zhang ◽  
Yongxia Li ◽  
Long Pan ◽  
Xuan Wang ◽  
Yuqian Feng ◽  
...  
Keyword(s):  
Parasitic Nematode ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pine Forests ◽  
Pinewood Nematode ◽  
Dispersal Stage ◽  
Pine Trees ◽  
The Common ◽  
Gradient Effects

AbstractPinewood nematode, Bursaphelenchus xylophilus, a pine parasitic nematode, poses a serious threat to its host pine forests globally. When dispersal-stage larvae 4 (dauer, DL4) of B. xylophilus enters the new pine, it moults into propagative adult (dauer recovery) and reproduces quickly to kill the host pine. Here, we found pine chemical volatiles, rather than the common dauer recovery factors of nematodes (e.g. suitable temperatures, nutrient availability or density), promote B. xylophilus dauer recovery. The results showed that volatilization of chemicals in host pines could attract DL4 and promote DL4 recovery. To identify which chemicals promote this process, we determined the stimulated activity of the main volatiles of pines including six monoterpenes and two sesquiterpenes. Results showed that all the six monoterpenes promoted dauer recovery, especially β-pinene and β-myrcene, but the two sesquiterpenes have no effect on the transformation. Furthermore, β-pinene performed gradient effects on dauer recovery. We hypothesized that when DL4 infect pine trees, the pine volatiles released from the feeding wounds are used as chemical signals for DL4 transformation to adult to reproduce and rapidly kill the pines. Our study identified the B. xylophilus dauer recovery chemical signal and may contribute to preventing pine wilt disease.

Presence of the cerambycid beetles Psacothea hilaris and Monochamus alternatus affecting the life cycle strategy of Bursaphelenchus xylophilus

Nematology ◽  
2001 ◽  
Vol 3 (5) ◽  
pp. 455-461 ◽  
Author(s):  
Noritoshi Maehara ◽  
Kazuyoshi Futai
Keyword(s):  
Life History ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Fourth Stage ◽  
Monochamus Alternatus ◽  
The Third ◽  
Life Cycle Strategy ◽  
Pine Trees ◽  
History Of ◽  
Cerambycid Beetles

AbstractAlthough fourth-stage dispersal juveniles (JIV) of Bursaphelenchus xylophilus, the pinewood nematode (PWN), developed in the presence of both Monochamus alternatus and Psacothea hilaris, the numbers and the percentage of JIV were far higher in the presence of the former than of the latter. JIV first appeared 7 days after pupation of M. alternatus and the number increased from the day of beetle eclosion to the third day thereafter, then remained stable. We conclude that the presence of specific vectors affects both the life history of the PWN and the numbers of nematodes carried by vectors emerging from killed pine trees.

scholarly journals A Reference Genome of Bursaphelenchus mucronatus Provides New Resources for Revealing Its Displacement by Pinewood Nematode

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 570
Author(s):  
Shuangyang Wu ◽  
Shenghan Gao ◽  
Sen Wang ◽  
Jie Meng ◽  
Jacob Wickham ◽  
...  
Keyword(s):  
Single Molecule ◽  
Native Species ◽  
Reference Genome ◽  
Draft Genome ◽  
Morphological Characteristics ◽  
Bursaphelenchus Xylophilus ◽  
Biological Properties ◽  
Pinewood Nematode ◽  
Competitive Displacement ◽  
Bursaphelenchus Mucronatus

The Bursaphelenchus mucronatus, which was highly similar with Bursaphelenchus xylophilus in terms of morphological characteristics and biological properties—but had weaker pathogenicity to forests—was a native species often displaced by B. xylophilus when occupying the same niche. Since the draft genome of the invasive B. xylophilus has been published, the absence of a reference genome of B. mucronatus still prevents us from understanding the molecular evidences behind competitive displacement. In this study, we employed Single Molecule, Real-Time (SMRT) sequencing and a Hi-C scaffolding approach to yield a near chromosome-level assembly of B. mucronatus, including six pseudo-chromosomes. The assembly size is 73 Mb, with scaffold N50 of 11.50 Mb and contig N50 of 1.48 Mb. Comparative genomics results showed high similarity between B. xylophilus and B. mucronatus. However, the losing of orphan genes and species-specific orthologous genes in B. mucronatus may indicate weaker adaptability to the environment. The gene family contractions of GPCRs (G Protein-Coupled Receptors) and cellulases in B. mucronatus may jointly contribute to its displacement by B. xylophilus. Overall, we introduced a valuable genomic resource for molecular and evolutionary studies of B. mucronatus, especially for studying the competitive displacement by the pinewood nematode, which could help us control the pathogenicity of pine wilt diseases.

scholarly journals Virulence of Bursaphelenchus xylophilus Isolated from Naturally Infested Pine Forests to Five Resistant Families of Pinus thunbergii

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 249-252 ◽  
Author(s):  
Mitsuteru Akiba ◽  
Makoto Ishihara ◽  
Norio Sahashi ◽  
Katsunori Nakamura ◽  
Mineko Ohira ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Breeding Program ◽  
Pinewood Nematode ◽  
Differential Host ◽  
Pine Trees ◽  
Efficient Breeding ◽  
Highly Virulent

Pine wilt disease is one of the most serious epidemic tree diseases in Japan, and resistant pine trees have been developed through a breeding program. To evaluate resistance of resistant families of Japanese black pine, Pinus thunbergii, to the pinewood nematode, Bursaphelenchus xylophilus, isolated from the field, and to determine whether differentiation of pathogenicity to resistant pine families appears in the nematode isolates, seedlings of five resistant pine families were inoculated with 25 nematode isolates. Disease incidence 18 weeks after inoculation was significantly different among nematode isolates and among pine families but there was no interaction effect between nematode isolate and pine family. This indicates that nematode isolates did not have differential host specificity to resistant families of P. thunbergii. Isolate Shimabara, a test isolate of the breeding program, showed the same degree of virulence as the highly virulent isolates frequently used in experiments. However, more virulent isolates than Shimabara were found among the isolates collected from natural pine forest. This indicated that B. xylophilus populations with higher virulence than Shimabara exist in the natural population. These findings are important in development of more efficient breeding procedures for resistant pine trees.

scholarly journals The specialization of Esteya vermicola hyphae in infection to Bursaphelenchus xylophilus and its colonization of pine tree

2020 ◽  
Author(s):  
Hai-Hua Wang ◽  
Can Yin ◽  
Jie Gao ◽  
Ran Tao ◽  
Piao-Piao Dai ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Fungal Colonization ◽  
Pinewood Nematode ◽  
Pine Tree ◽  
Pine Wilt ◽  
Pine Trees ◽  
Colonization Patterns ◽  
Esteya Vermicola

AbstractPine wilt disease (PWD) caused by the nematode Bursaphelenchus xylophilus is a serious problem on pines, and there is currently no effective control strategy for this disease. Although the endoparasitic fungus Esteya vermicola showed great effectiveness in controlling pine wilt disease, the colonization patterns of the host pine tree xylem by this fungus are unknown. To investigate the colonization patterns of pine xylem by this fungus, the species Pinus koraiensis grown in a greenhouse was used as an experimental host tree. The fungal colonization of healthy and wilting pine trees by E. vermicola was quantified using PCR with a TaqMan probe, and a green fluorescence protein (GFP) transformant was used for visualization. The results reported a specific infection approach used by E. vermicola to infect B. xylophilus and specialized fungal parasitic cells in PWN infection. In addition, the inoculated blastospores of E. vermicola germinated and grew inside of healthy pine xylem, although the growth rate was slow. Moreover, E. vermicola extended into the pine xylem following spray inoculation of wounded pine seedling stems, and a significant increase in fungal quantity was observed in response to B. xylophilus invasion. An accelerated extension of E. vermicola colonization was shown in PWN-infected wilting pine trees, due to the immigration of fungal-infected PWNs. Our results provide helpful knowledge about the extension rate of this fungus in healthy and wilting PWN-susceptible pine trees in the biological control of PWD and will contribute to the development of a management method for PWD control in the field.Author summaryPine wilt disease, caused by Bursaphelenchus xylophilus, has infected most pine forests in Asian and European forests and led to enormous losses of forest ecosystem and economy. Esteya vermicola is a bio-control fungus against pinewood nematode, showed excellent control efficient to pine wilt disease in both of greenhouse experiments and field tests. Although this bio-control agent was well known for the management of pine wilt disease, the infection mechanism of fungal infection and colonization of host pine tree are less understand. Here, we use GFP-tagged mutant to investigate the fungal infection to pinewood nematode; additionally, the temporal and spatial dynamics of E. vermicola colonize to pine tree were determined by the TaqMan real-time PCR quantification, as well as the response to pinewood nematode invasion. We found a specific infection approach used by E. vermicola to infect B. xylophilus and specialized fungal parasitic cells in PWN infection. In addition, the fungal germination and extension inside of pine tree xylem after inoculation were revealed. In addition, the quantity of E. vermicola increased as response to pinewood nematode invasion was reported. Our study provides two novel technologies for the visualization and detection of E. vermicola for the future investigations of fungal colonization and its parasitism against pinewood nematode, and the mechanisms of the bio-control process.

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