scholarly journals Behavior of the pine wood nematode, Bursaphelenchus xylophilus, and disease development in pine trees.

1990 ◽  
Vol 64 (7) ◽  
pp. 1243-1246 ◽  
Author(s):  
Yasuharu MAMIYA
Keyword(s):  
Bursaphelenchus Xylophilus ◽  
Disease Development ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Trees

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.

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.

scholarly journals Silencing of cyp-33C9 Gene Affects the Reproduction and Pathogenicity of the Pine Wood Nematode, Bursaphelenchus xylophilus

2019 ◽  
Vol 20 (18) ◽  
pp. 4520 ◽  
Author(s):  
Xiuwen Qiu ◽  
Lili Yang ◽  
Jianren Ye ◽  
Wei Wang ◽  
Tiantian Zhao ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Economic Losses ◽  
Parasitic Nematodes ◽  
Pine Wood Nematode ◽  
Egg Hatch ◽  
Pine Wood ◽  
Large Numbers ◽  
Cytochrome P450 Genes ◽  
Pine Trees

Cytochrome P450 genes are very important for plant-parasitic nematodes to reproduce and to metabolize xenobiotic compounds generated by their host plants. The pine wood nematode (PWN), Bursaphelenchus xylophilus, causes very high annual economic losses by killing large numbers of pine trees across Asia and into Europe. In this study, we used RNA interference (RNAi) to analyze the function of the cyp-33C9 gene of PWN. Our results showed that expression of the cyp-33C9 gene was suppressed successfully after soaking nematodes for 24 h in cyp-33C9 double-stranded RNA (dsRNA). The silencing of the cyp-33C9 gene significantly decreased the feeding, reproduction, oviposition and egg hatch of B. xylophilus. Meanwhile, the migration speed of B. xylophilus in Pinus thunbergii was reduced in the early stages when the cyp-33C9 gene was silenced in the nematodes. Moreover, knockdown of the cyp-33C9 gene in B. xylophilus caused a decrease in pathogenicity to pine trees. These results suggest that the cyp-33C9 gene plays an important role in the reproduction and pathogenicity of B. xylophilus. This discovery identified several functions of the cyp-33C9 gene in B. xylophilus and provided useful information for understanding the molecular mechanism behind pine wilt disease caused by PWN.

Cohabitation of the pine wood nematode, Bursaphelenchus xylophilus, and fungal species in pine trees inoculated with B. xylophilus

Nematology ◽  
2007 ◽  
Vol 9 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Kazuyoshi Futai ◽  
Rina Sriwati ◽  
Shuhei Takemoto
Keyword(s):  
Bursaphelenchus Xylophilus ◽  
Fungal Species ◽  
Pine Wood Nematode ◽  
Trichoderma Spp ◽  
Pine Wood ◽  
Positive Effects ◽  
Pine Trees ◽  
Old Japanese ◽  
Sphaeropsis Sapinea ◽  
The Relationship

AbstractThe relationship between the pine wood nematode (PWN), Bursaphelenchus xylophilus, and fungi cohabiting in 15-year-old Japanese black pine, Pinus thunbergii, was examined at intervals of 2 months over a year following inoculation with PWN. The population of PWN in the trees was large in August, but decreased slightly in December then increased again in February. Eighteen species of fungi were isolated from wood samples of the pine trees examined. Among them were Phialophora repens, Sphaeropsis sapinea, Pestalotiopsis spp. and Rhizoctonia sp., which were detected most frequently every season. All of these dominant fungi had positive effects on increasing the nematode population except for Rhizoctonia sp., on which PWN propagated less. Under laboratory conditions, 18 species of fungi isolated from pine trees and Botrytis cinerea cultured on potato dextrose agar served as food for PWN, and PWN population build up was compared at 20°C. PWN increased significantly on Pestalotiopsis sp. 1, Pestalotiopsis sp. 2, Sphaeropsis sapinea, Phialophora repens and B. cinerea from 10-15 days after inoculation. From the viewpoint of food quality and their cohabiting ability, we concluded that the species of fungi that were dominant in the pine trees, except for Rhizoctonia sp., had a compatible relationship with PWN, whilst Rhizoctonia sp. and Penicillium spp. were neutral, and Trichoderma spp. had an incompatible relationship with PWN.

A rapid in vitro bioassay system for testing resistance factors of pine trees to Bursaphelenchus xylophilus

Nematology ◽  
2013 ◽  
Vol 15 (6) ◽  
pp. 665-670
Author(s):  
Zhang Fujia ◽  
Zhang Fujia ◽  
Yasuhiro Mori ◽  
Zhang Fujia ◽  
Yasuhiro Mori ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Rapid Screening ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Resistance Factors ◽  
Methanol Extracts ◽  
Bioassay System ◽  
Pine Trees

Understanding resistance mechanisms to pine wilt disease is essential to a successful breeding programme because plant selection cannot always guarantee absolute resistance against every isolate of the pine wood nematode, Bursaphelenchus xylophilus. To examine resistance factors in Japanese black pine, Pinus thunbergii, we devised a novel in vitro bioassay system in which we tested proliferation of pine wood nematodes co-cultured with wood slices or methanol extracts from pines. Proliferation of pine wood nematodes was inhibited in assays with fresh wood slices from resistant Japanese black pines but not with susceptible pine or without wood slices (control). When resistant wood slices were extracted by methanol, the inhibition effect of proliferation of pine wood nematodes was diminished, whereas methanol extraction from susceptible wood slices did not affect the proliferation. To verify whether nematode proliferation was inhibited by pine extracts, methanol extracts were loaded on paper disks and used in the assay. Populations of pine wood nematodes were significantly suppressed when methanol extracts originated from a resistant pine, but not from a susceptible pine. These results strongly suggest that methanol extracts from resistant pine trees contain the inhibitors of pine wood nematode proliferation. This bioassay system is available not only for identifying inhibitors of pine wood nematode proliferation but also for rapid screening of resistant pines.

scholarly journals Comparison of Morphological Indexes and the Pathogenicity of Bursaphelenchus xylophilus in Northern and Southern China

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 310
Author(s):  
Qing-Qing Kong ◽  
Xiao-Lei Ding ◽  
Yi-Fan Chen ◽  
Jian-Ren Ye
Keyword(s):  
Southern China ◽  
Northern China ◽  
Bursaphelenchus Xylophilus ◽  
Northern Region ◽  
Liaoning Province ◽  
Pine Wood Nematode ◽  
Pine Wood ◽  
Pine Trees ◽  
The Difference ◽  
Different Strains

The pine wood nematode (PWN) Bursaphelenchus xylophilus is recognized as a major invasive species in many countries and causes widespread mortality in pine trees. Pine wood nematode disease (PWD) has spread northward from southern China to several areas of Liaoning Province, which has temperatures outside of the optimal range for this disease. To determine whether obvious variations in the population adaptability of PWN are involved in its rapid spread from southern to northern China, this study compared the differences in morphology of eight southern strains and eight northern strains and the pathogenicity of the 16 strains to Pinus thunbergii, the pine species that is the most susceptible to PWD in China, and to P. tabuliformis, the main PWN host in northern Liaoning Province. The southern-strain females were smaller than the northern-strain females, except for strain GD32. The size differences between the males of the different strains were not significant. The difference in pathogenicity between the northern and southern strains to P. tabuliformis was more significant than the difference in their pathogenicity to P. thunbergii. The pathogenicity differentiation among northern strains was lower than that among southern strains, and the northern strains showed stronger pathogenicity to P. tabuliformis. The P. tabuliformis inoculation experiment showed that the pathogenicity of GD32, JS27, FJ14, LN13, and LN06 was significantly higher than that of FJ13. The results suggest that some PWN populations in the southern region, which are better adapted to P. tabuliformis, were likely directly transmitted to the northern region, resulting in the spread of PWD in the northern region. The spread of PWN from the south did not necessarily require a process of adaptation to the host or to the northern climate.

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