scholarly journals Migration and Population Growth of the Pine Wood Nematode (Bursaphelenchus xylophilus) Related to the Symptom Development in the Seedlings of Japanese Black Pine (Pinus thunbergii) Families Selected as Resistant to Pine Wilt.

2007 ◽  
Vol 89 (4) ◽  
pp. 241-248 ◽  
Author(s):  
K. Kuroda ◽  
M. Ohira ◽  
M. Okamura ◽  
Y. Fujisawa
Keyword(s):  
Population Growth ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Black Pine ◽  
Pine Wood Nematode ◽  
Symptom Development ◽  
Pine Wood ◽  
Pine Wilt ◽  
Japanese Black Pine

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.

Influence of fungi on multiplication and distribution of the pine wood nematode, Bursaphelenchus xylophilus, in axenized Pinus thunbergii cuttings

Nematology ◽  
2005 ◽  
Vol 7 (6) ◽  
pp. 809-817 ◽  
Author(s):  
Kazuo Suzuki ◽  
Daisuke Sakaue ◽  
Toshihiro Yamada ◽  
Yu Wang
Keyword(s):  
Population Size ◽  
Early Stage ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Disease Development ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Inoculation Site ◽  
Fungal Hyphae ◽  
Close Relationship

AbstractInfluence of fungi on multiplication and distribution of the pine wood nematode (PWN), Bursaphelenchus xylophilus, was investigated in Pinus thunbergii cuttings. Axenized nematodes and/or one of two fungi isolated from healthy and PWN-killed P. thunbergii were inoculated together into autoclaved cuttings. A close relationship between the existence and distribution of fungal hyphae, and the multiplication and distribution of PWN was observed. The PWN did not multiply when only axenized nematodes were inoculated in the absence of fungi. When fungi were present, PWN population size increased markedly. The number of nematodes was high at sites where fungal hyphae were distributed. It is suggested that the restriction of a large portion of the nematode population near the inoculation site during the early stage of disease development is closely related to restricted distribution of fungal hyphae.

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.

Role of resin canals in the early stages of pine wilt disease caused by the pine wood nematode

1997 ◽  
Vol 75 (2) ◽  
pp. 346-351 ◽  
Author(s):  
Kyoko Ishida ◽  
Taizo Hogetsu
Keyword(s):  
Pine Wilt Disease ◽  
Wilt Disease ◽  
Pinus Thunbergii ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Wilt ◽  
Bark Peeling ◽  
Resin Canals ◽  
Cut Surface

The role of cortical resin canals in the early development of a pine wilt disease in Japanese black pine, Pinus thunbergii, was studied. A part of the bark of a 2 cm long segment from a current-year stem was removed by a tangential cut with a razor blade. Both cortex-exposed segments with cut cortical resin canals (designated as +RC segments) and those without cut resin canals (–RC segments) were obtained by chance. When a virulent nematode isolate (S6-1) was inoculated onto the cut surface, the surface of the +RC segments turned brown 4 d after inoculation, and in some segments this browning occurred more intensely around cortical resin canals. When segments were cut transversely at the middle, the transverse cut surface of the inoculated +RC segments was brown and fragile, but that of the inoculated –RC segments was pale green and stable, as was that of the non-inoculated controls. Correspondingly, tissue cells including epithelial cells of the cortical resin canal of the +RC segments were all dead, but those of the –RC segments and the controls were alive. When nematodes were inoculated onto the inner surface (cambium side) of a bark peeling at which cambial xylem cells were exposed, they did not kill the cambial cells. When inoculated on the transverse cut end of a bark peeling from which nematodes would enter resin canals, nematodes killed all cells in the peeling. The above results indicate that nematodes do not kill cortical cells immediately after inoculation but become harmful to pine cells after living in cortical resin canals. Key words: Bursaphelenchus xylophilus, pine wilt disease, pine wood nematode, Pinus thunbergii, resin canal.

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