scholarly journals Effects of Endobacterium (Stenotrophomonas maltophilia) on Pathogenesis-Related Gene Expression of Pine Wood Nematode (Bursaphelenchus xylophilus) and Pine Wilt Disease

2016 ◽  
Vol 17 (6) ◽  
pp. 778 ◽  
Author(s):  
Long-Xi He ◽  
Xiao-Qin Wu ◽  
Qi Xue ◽  
Xiu-Wen Qiu
2019 ◽  
Vol 51 (10) ◽  
pp. 1071-1078
Author(s):  
Xin Huang ◽  
Longjiao Hu ◽  
Xiaoqin Wu

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.


Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3729
Author(s):  
Weibin Wu ◽  
Zhenbang Zhang ◽  
Lijun Zheng ◽  
Chongyang Han ◽  
Xiaoming Wang ◽  
...  

Pine wilt disease (PWD) caused by pine wood nematode (PWN, Bursaphelenchus xylophilus) originated in North America and has since spread to Asia and Europe. PWN is currently a quarantine object in 52 countries. In recent years, pine wilt disease has caused considerable economic losses to the pine forest production industry in China, as it is difficult to control. Thus, one of the key strategies for controlling pine wilt disease is to identify epidemic points as early as possible. The use of hyperspectral cameras mounted on drones is expected to enable PWD monitoring over large areas of forest, and hyperspectral images can reflect different stages of PWD. The trend of applying hyperspectral techniques to the monitoring of pine wilt disease is analyzed, and the corresponding strategies to address the existing technical problems are proposed, such as data collection of early warning stages, needs of using unmanned aerial vehicles (UAVs), and establishment of models after preprocessing.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1679
Author(s):  
Juha Tuomola ◽  
Hannah Gruffudd ◽  
Kimmo Ruosteenoja ◽  
Salla Hannunen

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.


2021 ◽  
Vol 61 (4) ◽  
pp. 346-351

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.


Nematology ◽  
2003 ◽  
Vol 5 (6) ◽  
pp. 899-906 ◽  
Author(s):  
Bo Guang Zhao ◽  
Hu Li Wang ◽  
Su Fen Han ◽  
Zheng Ming Han

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.


Nematology ◽  
2014 ◽  
Vol 16 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Yan Gao ◽  
Yan Gao ◽  
Dongju Yuan ◽  
Yan Gao ◽  
Dongju Yuan ◽  
...  

Crude extracts of the surface coat (SC) proteins of the pine wood nematode (PWN), Bursaphelenchus xylophilus, and purified flagellin from Pseudomonas fluorescens (GcM5-1A) isolate were bioassayed using symbiontic GcM5-1A and axenic PWNs, respectively. The results showed that the flagellin significantly increased the reproduction of axenic PWN and the SC protein extracts of the PWN promoted GcM5-1A multiplication. The finding is a new step to further elucidate the symbiotic mechanism between the PWN and its associated bacteria and the SC protein function in pine wilt disease.


2007 ◽  
Vol 18 (4) ◽  
Author(s):  
Pedro Naves ◽  
Susana Camacho ◽  
Edmundo De Sousa ◽  
José Quartau

Transmission of Bursaphelenchus xylophilus (PWN) by the oviposition of Monochamus galloprovincialis was studied in Portugal. Female insects laid eggs on 77% of pine bolts on the laboratory, of which 37% became infected with PWN, with a mean of 290 nematodes. Inside the PWN affected zone 50 P. pinaster trap-trees were created between May and September 2001 and 2002, of which 29 were colonised by M. galloprovincialis and only four became infected by the nematode. The low transmission efficiency detected both on laboratory and field suggests that nematode transmission through the vector’s oviposition activity may be a secondary component of the pine wilt disease epidemiology in Portugal.


Nematology ◽  
2015 ◽  
Vol 17 (5) ◽  
pp. 581-589 ◽  
Author(s):  
Xiao-Jing Tian ◽  
Xiao-Qin Wu ◽  
Yang Xiang ◽  
Xin Fang ◽  
Jian-Ren Ye

Pine wilt disease (PWD) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, is a destructive forest disease. Recent studies showed that bacteria associated with PWN might play important roles in PWD. In this study, the effects of endobacteria isolated from PWN on the development and virulence of PWN were evaluated. The results revealed that endobacteria isolated from high virulence PWN could partially promote the development of the nematode, while endobacteria from PWN with low virulence could inhibit the development of nematode. Both bacteria-free and non-sterilised nematodes were able to infect microcuttings of Pinus densiflora. The endobacterial isolates, Stenotrophomonas maltophilia NSBx.14 and Achromobacter xylosoxidans ssp. xylosoxidans NSBx.22, enhanced the virulence of low virulence PWN but reduced the virulence of high virulence PWN. The results suggest the pathogenicity of PWN is not affected by loss of bacteria and endobacteria might play a role in the development and virulence of PWN.


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