Resistance of an indigenous biological system against expansion of the invasive nematode, Bursaphelenchus xylophilus, in cool areas of Japan

Nematology ◽  
2008 ◽  
Vol 10 (5) ◽  
pp. 679-687 ◽  
Author(s):  
Shota Jikumaru ◽  
Katsumi Togashi
Keyword(s):  
Air Temperature ◽  
Pinus Densiflora ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Vector System ◽  
Insect Vector ◽  
Disease Development ◽  
Biotic Factors ◽  
Pine Tree ◽  
Pine Trees

Abstract Bursaphelenchus xylophilus is the pathogen associated with pine wilt disease (PWD), an infectious disease of pine trees transmitted by cerambycid beetles of the genus Monochamus. Bursaphelenchus xylophilus is an invasive species, whilst B. mucronatus is a native congener and non-pathogenic to pine trees in Japan. To provide experiment evidence of the biotic and/or abiotic resistance to PWD expansion in a cool area of Japan, we inoculated B. xylophilus into healthy pine trees in a Japanese red pine (Pinus densiflora) stand with the indigenous pine tree-B. mucronatus-insect vector system before invasion of B. xylophilus in 1993 and 1994. Extremely cool air temperature with high precipitation and extremely high air temperature with low precipitation were observed in the summers of the 2 years of inoculation, respectively. The cool summer induced a low incidence of PWD and delayed disease development, resulting in the replacement of B. xylophilus by B. mucronatus within diseased trees and the emergence of Monochamus saltuarius beetles carrying B. mucronatus from the trees 2 years after the inoculation. The hot summer induced disease development in trees in the year of inoculation, but such diseased trees did not become infection sources because of the lack of M. alternatus, whose oviposition was synchronised with the period of disease development in pine trees. This study indicated that biotic factors were important in the inhibitory mechanism in a pine forest against the spread of PWD in the stand. Relevant biotic factors were the lack of M. alternatus and the presence of M. saltuarius carrying B. mucronatus.

Boarding abilities of Bursaphelenchus mucronatus and B. xylophilus (Nematoda: Aphelenchoididae) on Monochamus alternatus (Coleoptera: Cerambycidae)

Nematology ◽  
2003 ◽  
Vol 5 (6) ◽  
pp. 843-849 ◽  
Author(s):  
Shota Jikumaru ◽  
Katsumi Togashi
Keyword(s):  
Pine Wilt Disease ◽  
Nematode Species ◽  
Bursaphelenchus Xylophilus ◽  
Insect Vector ◽  
Species Replacement ◽  
Monochamus Alternatus ◽  
Bursaphelenchus Mucronatus ◽  
Initial Load ◽  
Pine Trees ◽  
The Difference

Abstract Bursaphelenchus mucronatus is closely related to Bursaphelenchus xylophilus, the causative agent of pine wilt disease. Both nematodes are transmitted between host pine trees as the fourth-stage dispersal juveniles (JIV) by insect vectors. After the invasion of Japan by B. xylophilus, B. mucronatus, native to Japan, appears to have been replaced in the pine forests during the spread of the disease. To help understand this species replacement, the number of JIV carried by an insect vector (the initial nematode load) was compared between the two nematode species by using the beetle, Monochamus alternatus, in the laboratory. The initial load of B. mucronatus was significantly smaller than that of B. xylophilus although the number of third-stage dispersal juveniles (JIII) concentrated at the pupal chambers did not differ. Statistical analysis showed that the proportion of JIII moulting to JIV was the most important among three components explaining the difference in the initial load of B. mucronatus while the number of JIII concentrated at the pupal chamber was the most important for B. xylophilus. The phoretic affinity between the nematode and its vector is discussed in relation to its role in the species replacement.

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.

Is Bursaphelenchus mucronatus a weak pathogen to the Japanese red pine?

Nematology ◽  
2006 ◽  
Vol 8 (4) ◽  
pp. 485-489 ◽  
Author(s):  
Kazuyoshi Futai ◽  
Natsumi Kanzaki
Keyword(s):  
Pinus Densiflora ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Transmission Efficiency ◽  
Monochamus Alternatus ◽  
Disease Symptoms ◽  
Host Trees ◽  
Bursaphelenchus Mucronatus ◽  
Pine Trees ◽  
Mutualistic Relationship

AbstractThe pine wood nematode, Bursaphelenchus xylophilus, is the causal agent of pine wilt disease. It can invade healthy pine trees through the feeding wound of its vector beetle, Monochamus alternatus, and can enter a dead or dying tree through the vector's oviposition mark. By contrast, B. mucronatus, which is closely related to B. xylophilus but has been considered to have no pathogenicity to pine species, also invades living host trees through the same process as B. xylophilus, although the transmission efficiency is lower than that of B. xylophilus. In order to clarify the reason why Bursaphelenchus mucronatus invades a living host, we inoculated shaded and unshaded host seedlings of Pinus densiflora with B. mucronatus. Bursaphelenchus mucronatus displayed pathogenicity in the host seedlings but only with those that were shaded. In addition, B. mucronatus was recovered from the seedlings that had survived until the end of the experiment. Bursaphelenchus mucronatus seems to survive in the living healthy host tree without causing disease symptoms. These results suggest a mutualistic relationship between B. mucronatus and its vector beetle.

scholarly journals Early detection of pine wilt disease in Pinus tabuliformis in North China using a field portable spectrometer and UAV-based hyperspectral imagery

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Run Yu ◽  
Lili Ren ◽  
Youqing Luo
Keyword(s):  
Early Stage ◽  
Vegetation Indices ◽  
Pine Wilt Disease ◽  
Wilt Disease ◽  
Pinus Tabulaeformis ◽  
Pine Tree ◽  
Preventative Measures ◽  
Pine Wilt ◽  
Pine Trees ◽  
Airborne Vehicle

Abstract Background Pine wilt disease (PWD) is a major ecological concern in China that has caused severe damage to millions of Chinese pines (Pinus tabulaeformis). To control the spread of PWD, it is necessary to develop an effective approach to detect its presence in the early stage of infection. One potential solution is the use of Unmanned Airborne Vehicle (UAV) based hyperspectral images (HIs). UAV-based HIs have high spatial and spectral resolution and can gather data rapidly, potentially enabling the effective monitoring of large forests. Despite this, few studies examine the feasibility of HI data use in assessing the stage and severity of PWD infection in Chinese pine. Method To fill this gap, we used a Random Forest (RF) algorithm to estimate the stage of PWD infection of trees sampled using UAV-based HI data and ground-based data (data directly collected from trees in the field). We compared relative accuracy of each of these data collection methods. We built our RF model using vegetation indices (VIs), red edge parameters (REPs), moisture indices (MIs), and their combination. Results We report several key results. For ground data, the model that combined all parameters (OA: 80.17%, Kappa: 0.73) performed better than VIs (OA: 75.21%, Kappa: 0.66), REPs (OA: 79.34%, Kappa: 0.67), and MIs (OA: 74.38%, Kappa: 0.65) in predicting the PWD stage of individual pine tree infection. REPs had the highest accuracy (OA: 80.33%, Kappa: 0.58) in distinguishing trees at the early stage of PWD from healthy trees. UAV-based HI data yielded similar results: the model combined VIs, REPs and MIs (OA: 74.38%, Kappa: 0.66) exhibited the highest accuracy in estimating the PWD stage of sampled trees, and REPs performed best in distinguishing healthy trees from trees at early stage of PWD (OA: 71.67%, Kappa: 0.40). Conclusion Overall, our results confirm the validity of using HI data to identify pine trees infected with PWD in its early stage, although its accuracy must be improved before widespread use is practical. We also show UAV-based data PWD classifications are less accurate but comparable to those of ground-based data. We believe that these results can be used to improve preventative measures in the control of PWD.

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 Pseudomonas associated with Bursaphelenchus xylophilus, its insect vector and the host tree: A role in pine wilt disease?

2019 ◽  
Vol 49 (6) ◽  
pp. e12564
Author(s):  
Marta Salgueiro Alves ◽  
Anabela Pereira ◽  
Cláudia Vicente ◽  
Manuel Mota ◽  
Isabel Henriques
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Host Tree ◽  
Insect Vector ◽  
Pine Wilt

Volatile compounds in pine stands suffering from pine wilt disease: qualitative and quantitative evaluation

Nematology ◽  
2006 ◽  
Vol 8 (6) ◽  
pp. 869-879 ◽  
Author(s):  
Kazuyoshi Futai ◽  
Natsumi Kanzaki ◽  
Yuko Takeuchi
Keyword(s):  
Volatile Compounds ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Economic Damage ◽  
Qualitative And Quantitative ◽  
Pine Wilt ◽  
Pine Trees ◽  
Quantitative Properties ◽  
Pine Stands

AbstractPine wilt disease causes ecological and economic damage in Japanese pine forests in spite of intensive effort to protect them from the pine wood nematode, Bursaphelenchus xylophilus. Pine trees infected with B. xylophilus emit a characteristic bouquet of volatile compounds bioactive to the vector beetle of the nematode, Monochamus alternatus, and potentially affecting symptom development inside the trees. To investigate the qualitative and quantitative properties of volatile compounds in the field, we profiled the volatile emissions in two Japanese black pine stands, one naturally suffering from pine wilt disease and the other artificially inoculated with B. xylophilus. In both pine stands, the emission of some terpenoids from the infected trees such as (−)-α-pinene, began to increase in summer, overlapping the oviposition season of the vector beetle, but peaked in the summer and autumn. These data suggest that the beetles may not necessarily depend on the tremendous quantity of volatiles alone when they search for suitable trees on which to oviposit.

Inhibition response of Pinus densiflora clones to Bursaphelenchus xylophilus systemic dispersal and their resistance to pine wilt disease

Nematology ◽  
2011 ◽  
Vol 13 (6) ◽  
pp. 653-659 ◽  
Author(s):  
Katsumi Togashi ◽  
Hiroko Maezono ◽  
Koji Matsunaga ◽  
Satoshi Tamaki
Keyword(s):  
Pinus Densiflora ◽  
Resistance Mechanism ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pine Wilt ◽  
Inhibition Response ◽  
The Mean ◽  
The Relationship ◽  
Clone Group

AbstractTo determine the relationship between resistance to pine wilt disease and the inhibition of nematode systemic dispersal in Pinus densiflora, a suspension of 200 Bursaphelenchus xylophilus was placed on the upper cut end of 5-cm-long, living or boiled branch sections of 17 clones of pine that had different resistance levels. Significantly more nematodes passed through boiled sections than living sections during 24 h. Living branches of the resistant P. densiflora clone group significantly suppressed the dispersal of B. xylophilus compared with those of the susceptible group, suggesting that the inhibition of nematode systemic dispersal was involved in the resistance mechanism of selected disease-resistant pine clones. However, there was no significant correlation between the resistance class and the mean number of nematodes passing through live branch sections within the resistant clone group. The reason for the lack of correlation is discussed in relation with the resistance mechanism.

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.

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