scholarly journals Could Pine Wood Nematode (Bursaphelenchus xylophilus) Cause Pine Wilt Disease or Even Establish inside Healthy Trees in Finland Now—Or Ever?

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1679
Author(s):  
Juha Tuomola ◽  
Hannah Gruffudd ◽  
Kimmo Ruosteenoja ◽  
Salla Hannunen
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pine Wood Nematode ◽  
The European Union ◽  
Climate Data ◽  
Worst Case ◽  
Pine Wood ◽  
Pine Wilt ◽  
Temperature Concept

Pine wilt disease (PWD) caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus) can, in suitable conditions, lead to mass mortality of susceptible trees. In the European Union, PWN is a quarantine pest. To support PWN risk management in Finland, we assessed the suitability of the Finnish present and future climate for both PWD and PWN establishment inside susceptible healthy trees. The former was done using the mean summer temperature concept and the latter by relating annual growing degree days to the likelihoods of PWN extinction and establishment inside healthy trees. The likelihoods were derived from the previously published modelling of PWN population dynamics for 139 locations in Germany. Both assessments were conducted using 10 × 10 km resolution climate data from 2000–2019 and Finland-specific climate change projections for 2030–2080. The results indicate that the present Finnish climate is too cool for both PWD and PWN establishment inside healthy trees. Furthermore, even global warming does not appear to turn the Finnish climate suitable for PWD or PWN establishment inside healthy trees by 2080, except under the worst-case representative concentration pathway scenario (RCP8.5). Consequently, giving top priority to PWN when allocating resources for biosecurity activities in Finland might deserve reconsideration.

Identification of a novel effector BxSapB3 that enhances the virulence of pine wood nematode Bursaphelenchus xylophilus

2019 ◽  
Vol 51 (10) ◽  
pp. 1071-1078
Author(s):  
Xin Huang ◽  
Longjiao Hu ◽  
Xiaoqin Wu
Keyword(s):  
Virulent Strain ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pcr Analysis ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Early Stages ◽  
Pine Wilt ◽  
Weakly Virulent

Abstract Pine wilt disease, caused by the pine wood nematode Bursaphelenchus xylophilus, leads to severe damage to pine forests in China. In our previous study, effectors secreted by this pathogen were shown to play roles in the different infection stages of pine wilt disease, and a series of candidate effectors were predicted by transcriptome sequencing. This study identified and characterized a novel effector, BxSapB3, which was among these candidate effectors. Agrobacterium-mediated transient expression was used to identify BxSapB3. BxSapB3 was secreted by B. xylophilus and found to be capable of inducing cell death in Nicotiana benthamiana. Quantitative real-time PCR (qRT-PCR) analysis revealed that BxSapB3 was upregulated in a highly virulent strain of B. xylophilus and expressed at lower levels in a weakly virulent strain at the early stages of infection. When BxSapB3 was silenced in B. xylophilus, the process of infection was delayed. These results indicate that BxSapB3 acts as an effector and contributes to virulence at the early stages of B. xylophilus infection.

scholarly journals Assessment of the PCR technique for identification of Bursaphelenchus mucronatus Mamiya & Enda 1979, B. xylophilus Steiner & Buhrer 1934 (Nickle 1970) and B. fraudulentus Rühm 1956 (Nematoda, Aphelenchoididae) in crude extract of nematodes isolated from wood

2021 ◽  
Vol 61 (4) ◽  
pp. 346-351
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Coniferous Forests ◽  
Pine Wood Nematode ◽  
Direct Examination ◽  
Pine Wood ◽  
Pine Wilt ◽  
Detection And Identification ◽  
Pine Trees

The pine wood nematode, Bursaphelenchus xylophilus Steiner & Buhrer 1934 (Nickle 1970) is the major causative agent of the pine wilt disease which has become devastating to Asian and European coniferous forests. These regions are also naturally occupied by two other native but nonpathogenic species, i.e. B. mucronatus Mamiya & Enda 1979 and B. fraudulentus Rühm 1956 which are closely related to the invasive B. xylophilus. Moreover, all these three species can colonize pine trees, and potentially be extracted from the same wood samples. Due to the cosmopolitan character and wide genetic variation within- and between existing populations the taxonomic distinction of these species based exclusively on their morphology is difficult or, almost impossible. The present quarantine regulations related to B. xylophilus require the most credible and simple methods which could allow for a possibly earliest detection and precise identification of this species in wood shipments and conifer forests stands. The main objectives of the presently reported research were to simplify the presently available procedures for possibly fast and precise detection and identification of B. xylophilus examined in the background of the remaining Bursaphelenchus species of the xylophilus group and other bacterio- and mycetophagous nematodes naturally present in the pine wood samples. The developed method is based on a direct examination of the crude nematode extract from wood samples and subsequent use of PCR technique with earlier designed specific reaction starters amplifying ITS1–28S rDNA regions.

Distribution and pathogenicity of bacteria species carried by Bursaphelenchus xylophilus in China

Nematology ◽  
2003 ◽  
Vol 5 (6) ◽  
pp. 899-906 ◽  
Author(s):  
Bo Guang Zhao ◽  
Hu Li Wang ◽  
Su Fen Han ◽  
Zheng Ming Han
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pinus Thunbergii ◽  
Automatic Testing ◽  
Pine Wood Nematode ◽  
Field Inoculation ◽  
Pine Wood ◽  
Pine Wilt

Abstract Bacteria carried by the pine wood nematode (PWN), Bursaphelenchus xylophilus, from both healthy and diseased Pinus thunbergii and P. massoniana were studied in five main pine wilt disease epidemic provinces in P. R. China. No bacteria were found in healthy pines but were found on PWN from all samples collected from diseased trees. Twenty-four bacteria strains were isolated from the nematodes and were identified by a combination of classical and automatic testing bacteriology (ATB) expression methods. Bioassay showed that 17 of the 24 identified strains produced phytotoxins. Eleven of these 17 phytotoxin producers belonged to the genus Pseudomonas. Glasshouse and field inoculation tests using sterile techniques showed that both PWN and the toxin-producing bacteria carried were necessary to induce disease. We hypothesise that pine wilt disease is a complex, induced by both PWN and the bacteria it carries.

scholarly journals Effects of Several Chemicals on the Migration Behavior of Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 771
Author(s):  
Xiu-Feng Shi ◽  
Xiao-Lei Ding ◽  
Li-Na Shi ◽  
Qing-Tong Wang ◽  
Jian-Ren Ye
Keyword(s):  
Pine Wilt Disease ◽  
Propagation Rate ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Movement Behavior ◽  
Insect Vector ◽  
Migration Behavior ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Wilt

The pine wood nematode (PWN), Bursaphelenchus xylophilus, that causes pine wilt disease (PWD), has severely damaged forests and ecosystems in countries of East Asia and Europe. Since the high propagation rate of PWD is the main cause of the devastating disease, it is very important to interfere with the spread of PWN mediated by its insect vector (Monochamus alternatus). In order to explore new methods and approaches for the prevention and control of pine wood nematode disease, chemicals with attraction or repellency to pine wood nematode and stable diffusion or volatilization in infected wood were screened out to interfere and hinder the pupa chamber effect, the aggregation behavior of PWN to pupa chamber in M. alternatus. In the present study, 22 chemicals were inoculated on water agar medium and infected wood to verify the tropism of PWN toward the chemicals from the aspects of attraction and repellency. The results indicate that linoleic acid, oleic acid, diacetyl and β-myrcene have attractive effects on PWN, while kerosene and β-humulene have repellent effects on PWN and are able to stably permeate and volatilize within pine trees. This research shows that some chemicals can affect the movement behavior of PWN and interfere with its migration to the pupal chamber in M. alternatus, thus reducing the dispersal efficiency of PWNs carried by insect vectors. This chemically based strategy would provide novel approaches for effective controlling of pine wilt disease.

How different is induced host resistance against the pine wood nematode, Bursaphelenchus xylophilus, by two avirulent microbes?

Nematology ◽  
2006 ◽  
Vol 8 (3) ◽  
pp. 435-442 ◽  
Author(s):  
Yuko Takeuchi ◽  
Natsumi Kanzaki ◽  
Kazuyoshi Futai
Keyword(s):  
Induced Resistance ◽  
Host Resistance ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Wilt ◽  
Pine Trees ◽  
Induce Resistance

AbstractPine wilt disease, caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, has been devastating pine forests in Japan for a century but an effective method for controlling the disease is still needed. Pre-inoculation of the host plant with an avirulent pathogen can induce resistance against subsequent infection with virulent pathogens; this is called 'induced resistance'. Host pine trees have this type of resistance against pine wilt disease but the detailed mechanism is unknown. In this study, 1-year-old potted seedlings of the susceptible Japanese black pine, Pinus thunbergii, were pre-inoculated with an avirulent isolate of PWN (C14-5), as well as an avirulent fungus, Botrytis cinerea, to induce host resistance against PWN. One, 2, 3, 4 and 5 weeks after inoculation, the seedlings were challenged with a virulent isolate of PWN (S10), and the survival of these seedlings was estimated by their external symptoms. Pre-inoculation with either C14-5 or Botrytis delayed the symptom development caused by subsequent inoculation with S10, suggesting that pre-inoculation induced host resistance against PWN. The resistance induced by pre-inoculation with C14-5 lasted for at least 5 weeks, while that induced by Botrytis weakened with time. It has been reported that the PWN survives inside the host seedlings for a long period without causing any symptoms under certain conditions, but Botrytis survives only for a while in the seedlings. Thus, the duration of host resistance induced by pre-inoculation may vary with the viability of the inoculum used for pre-inoculation. In order to obtain durable induced resistance, it may be necessary to repeat inoculations of avirulent microbes to be able to control pine wilt disease.

Pyochelin isolated from Burkholderia arboris KRICT1 carried by pine wood nematodes exhibits phytotoxicity in pine callus

Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 521-528 ◽  
Author(s):  
Quang Le Dang ◽  
Seung Wan Son ◽  
Hyang-Mi Cheon ◽  
Gyung Ja Choi ◽  
Yong Ho Choi ◽  
...  
Keyword(s):  
Complex Disease ◽  
Pinus Densiflora ◽  
Fermentation Broth ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Phytotoxic Activity ◽  
Pine Wilt

Abstract Pine wilt disease is a very complex disease known to be caused by the pine wood nematode, Bursaphelenchus xylophilus, and its accompanying bacteria. The phytotoxin-producing bacteria have been reported to be involved in the development of pine wilt disease. In this study, we attempted to characterise phytotoxins produced by Burkholderia arboris KRICT1, which was carried by the pine wood nematode. It produced phytotoxic compounds in the pine seedling assay, and the ethyl acetate (EtOAc) layer of the fermentation broth of the strain displayed phytotoxic activity on the pine callus of Pinus densiflora. One active compound was isolated from the EtOAc layer by repeated Sephadex LH-20 column chromatography and preparative TLC. Using mainly mass spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, the chemical structure was determined to be that of pyochelin (a mixture of two interconvertible diastereoisomers, pyochelin I and II). Pyochelin exposure reduced the viability of pine callus. Compared with phenylacetic acid, a phytotoxin produced by Bacillus spp. that was transmitted by B. xylophilus in Japan, pyochelin showed much stronger phytotoxicity. The results suggested that pyochelin might play a role in the wilting process of pine wilt disease.

Community and functional diversity of bacteria associated with propagative and dispersal forms of Bursaphelenchus xylophilus

Nematology ◽  
2016 ◽  
Vol 18 (10) ◽  
pp. 1185-1198 ◽  
Author(s):  
Xiao-Qin Wu ◽  
Qi Xue ◽  
Yang Xiang ◽  
Xiao-Lei Ding ◽  
Xiao-Lu Xu ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Sequencing ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Total Carbon ◽  
Insect Vector ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Wilt

The pine wood nematode (PWN),Bursaphelenchus xylophilus, the pathogen of pine wilt disease, has propagative and dispersal forms in its life cycle, which is associated with the insect vectorMonochamus alternatus. Pine wood nematode-associated bacteria could play important roles in pine wilt disease. In this study, the diversity and population dynamics of bacteria in propagative and dispersal stages of PWN were analysed using cultural and Biolog Eco™ methods coupled with high-throughput sequencing. The results revealed that culturableStenotrophomonasin PWN from diseased pine was not found fromM. alternatus. Bacteria in dispersal PWN carried byM. alternatusshowed the highest total carbon utilisation. The high-throughput analysis showed thatStenotrophomonas,AchromobacterandSphingobacteriumwere more abundant in propagative PWN than in dispersal PWN, whereasCitrobacter,Vibrioand Enterobacteriaceae were more abundant in dispersal PWN. The results showed that bacteria of PWN in different developmental forms differed. This change of bacteria might help PWN to adapt to the changing environment.

scholarly journals Comparison of the Surface Coat Proteins of the Pine Wood Nematode Appeared During Host Pine Infection and In Vitro Culture by a Proteomic Approach

2010 ◽  
Vol 100 (12) ◽  
pp. 1289-1297 ◽  
Author(s):  
Ryoji Shinya ◽  
Hironobu Morisaka ◽  
Yuko Takeuchi ◽  
Mitsuyoshi Ueda ◽  
Kazuyoshi Futai
Keyword(s):  
Immune Response ◽  
Pine Wilt Disease ◽  
Host Immune Response ◽  
Wilt Disease ◽  
Surface Coat ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Wilt ◽  
Proteomic Approach ◽  
Plant Parasitic

Pine wilt disease, caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, has become of worldwide quarantine concern in recent years. Here, we disclosed the surface coat (SC) proteins of the PWN which are thought to be one of the key components in pine wilt development. This is the first report that focused on the SC proteins and thoroughly identified those proteins of a plant-parasitic nematode using the proteomic approach. In this study, SC protein profiles were compared for PWNs grown on the fungus Botrytis cinerea and in host pine seedlings. The results demonstrated that the gross amount of PWN SC proteins drastically increased during infection of the host pine. Thirty-seven protein bands showed significant quantity differences between fungus-grown and host-origin PWNs, and were used for identification by matrix-assisted laser desorption ionization time of flight mass spectrometry analysis. These included several proteins that are presumed to be involved in the host immune response; for example, regulators of reactive oxygen species (ROS) and a ROS scavenger. These results might suggest that the PWN SC proteins are crucial in modulating or evading host immune response. Our data provide a new insight into the mechanism of pine wilt disease and the biological role of the SC proteins of plant-parasitic nematodes.

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