scholarly journals Early Symptom Development and Histological Changes Associated with Migration of Bursaphelenchus xylophilus in Seedling Tissues of Pinus thunbergii

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 675-680 ◽  
Author(s):  
Y. Ichihara ◽  
K. Fukuda ◽  
K. Suzuki
Keyword(s):  
Cell Death ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Pinewood Nematode ◽  
Symptom Development ◽  
Cortical Tissue ◽  
Early Symptom ◽  
Disease Symptoms ◽  
Virulent Isolate ◽  
Resin Canals

In order to clarify the mechanism of pine wilt caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus, nematode migration in tissues and disease symptoms in Pinus thunbergii seedlings were investigated. One-year-old seedlings were inoculated with different pathogenic isolates of PWN under two different temperatures. At an early stage of symptom development, a virulent isolate of PWN multiplied in both bark and xylem and was distributed in cortical resin canals, cortical tissue, and xylem resin canals at 30°C. Cell death and disease symptoms developed in both bark and xylem. The virulent isolate of PWN at 25°C and the avirulent isolate of PWN at 30°C were distributed mainly in cortical resin canals, but rarely in xylem resin canals and cortical tissue. Disease symptoms and cell death occurred in cortical resin canals and rarely occurred in other tissues. These results demonstrated that the virulent isolate of PWN at low temperature and avirulent nematodes could not easily migrate to xylem resin canals and cortical tissue. It was shown that cell death and early symptom development coincided with PWN migration and, therefore, PWN invasion induces cell death and early symptom development.

Cortical responses in Japanese black pine to attack by the pine wood nematode

1993 ◽  
Vol 71 (11) ◽  
pp. 1399-1405 ◽  
Author(s):  
Kyoko Ishida ◽  
Taizo Hogetsu ◽  
Kenji Fukuda ◽  
Kazuo Suzuki
Keyword(s):  
Early Stage ◽  
Bursaphelenchus Xylophilus ◽  
Black Pine ◽  
Pine Wood Nematode ◽  
Cortical Tissue ◽  
Pine Wood ◽  
Virulent Isolate ◽  
Bursaphelenchus Mucronatus ◽  
Resin Canals ◽  
Avirulent Isolate

Anatomical and cytochemical changes in the current-year stem cuttings of Japanese black pine (Pinus thunbergii) were investigated in the early stage of infection by a virulent isolate and an avirulent isolate of pine-wood nematode (Bursaphelenchus xylophilus), and an avirulent isolate of another nematode species, Bursaphelenchus mucronatus. Accumulation of lignin- and suberin-like substances around the resin canals in the cortex was shown as a new symptom of the infection by these isolates. Experiments with girdled cuttings demonstrated that more nematodes inhabit and move in the bark than in the xylem and pith at the early stage of infection by the virulent isolate. Death of pine cells occurred first in the epithelial cells of resin canals in the cortex after inoculation with the virulent isolate and then in the cortex and periderm, pith and xylem, and finally the cambium. In branches of 5-year-old seedlings inoculated with avirulent and B. mucronatus isolates, wound periderm was formed surrounding resin canals in the cortex, and cortical cells surrounding the wound periderm were alive. Evidence indicates that nematodes first enter resin canals in the cortex and then invade the surrounding cortical tissue, and that the ability of the virulent nematodes to move into the cortical tissue may be greater than that of the other isolates, accounting for differences in virulence. Key words: Bursaphelenchus xylophilus, Bursaphelenchus mucronatus, virulence, periderm, pine wilt disease, pine-wood nematode.

scholarly journals α-l-Fucosidases from Bursaphelenchus xylophilus Secretome—Molecular Characterization and Their Possible Role in Breaking Down Plant Cell Walls

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 265
Author(s):  
Joana M.S. Cardoso ◽  
Luís Fonseca ◽  
Isabel Abrantes
Keyword(s):  
Cell Wall ◽  
Molecular Characterization ◽  
Three Dimensional ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes ◽  
Host Trees ◽  
Resin Canals

The pinewood nematode (PWN) Bursaphelenchus xylophilus, the causal agent of the pine wilt disease (PWD), enters above-ground parts of the tree, migrates through the resin canals and feeds on plant cells causing extensive damage. In order to penetrate the cell wall and establish a parasitic relationship with host trees, the PWN needs to secretea mixture of active cell wall degrading enzymes. In maritime pine, Pinus pinaster, which is high susceptible to PWN, xyloglucan is the major hemicellulosic polysaccharide in primary cells. The xyloglucan backbone is susceptible to hydrolysis by numerous endoglucanases, some of them specific to xyloglucan. However, to completely degrade xyloglucan, all substitutions on the glucan backbones must be released, and l-fucose residues in xyloglucan branches are released by α-l-fucosidases. In the present study, the molecular characterization of two α-l-fucosidases found in PWN secretome was performed. Moreover, a novel α-l-fucosidase was identified and its cDNA and gene sequence were determined. The three-dimensional structures of these α-l-fucosidases were predicted and the transcript levels were analyzed, thus providing new insights into fundamental PWN biology and the possible role of these proteins as cell wall degrading enzymes.

scholarly journals Virulence of Bursaphelenchus xylophilus Isolated from Naturally Infested Pine Forests to Five Resistant Families of Pinus thunbergii

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 249-252 ◽  
Author(s):  
Mitsuteru Akiba ◽  
Makoto Ishihara ◽  
Norio Sahashi ◽  
Katsunori Nakamura ◽  
Mineko Ohira ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Breeding Program ◽  
Pinewood Nematode ◽  
Differential Host ◽  
Pine Trees ◽  
Efficient Breeding ◽  
Highly Virulent

Pine wilt disease is one of the most serious epidemic tree diseases in Japan, and resistant pine trees have been developed through a breeding program. To evaluate resistance of resistant families of Japanese black pine, Pinus thunbergii, to the pinewood nematode, Bursaphelenchus xylophilus, isolated from the field, and to determine whether differentiation of pathogenicity to resistant pine families appears in the nematode isolates, seedlings of five resistant pine families were inoculated with 25 nematode isolates. Disease incidence 18 weeks after inoculation was significantly different among nematode isolates and among pine families but there was no interaction effect between nematode isolate and pine family. This indicates that nematode isolates did not have differential host specificity to resistant families of P. thunbergii. Isolate Shimabara, a test isolate of the breeding program, showed the same degree of virulence as the highly virulent isolates frequently used in experiments. However, more virulent isolates than Shimabara were found among the isolates collected from natural pine forest. This indicated that B. xylophilus populations with higher virulence than Shimabara exist in the natural population. These findings are important in development of more efficient breeding procedures for resistant pine trees.

The process of epithelial cell death in Pinus thunbergii caused by the pine wood nematode, Bursaphelenchus xylophilus

Nematology ◽  
2014 ◽  
Vol 16 (6) ◽  
pp. 663-668 ◽  
Author(s):  
Joung A. Son ◽  
Joung A. Son ◽  
Taizo Hogetsu ◽  
Joung A. Son ◽  
Taizo Hogetsu ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Pine Wood Nematode ◽  
Stem Cuttings ◽  
Pine Wood ◽  
A New Technique ◽  
Resin Canals ◽  
Epithelial Cell Death

This study describes a new technique to investigate how the pine wood nematode (PWN), Bursaphelenchus xylophilus, kills pine epithelial cells. After inoculating PWN into 20-cm-long Pinus thunbergii stem cuttings and incubating for 1, 3 or 7 days, the cuttings were split into 2.5 cm segments. The segments were tangentially cut so that the epithelia of several cortical resin canals were exposed, and these were stained with Evans Blue for the detection of dead epithelial cells. While almost no dead epithelial cells were found in the cortical resin canals of non-PWN-inoculated control cuttings up to day 7 of the experiment, dead epithelial cells were distributed sparsely in the epithelium of cortical resin canals throughout pine cuttings inoculated with PWN 1, 3 and 7 days after inoculation. The sparse and sporadic distribution of dead pine cells in the epithelium suggested that individual PWN attacked one epithelial cell at a time with its stylet and migrated between attacks.

scholarly journals A Review on the Nematicidal Activity of Volatile Allelochemicals against the Pinewood Nematode

2020 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Jorge M. S. Faria ◽  
Pedro Barbosa ◽  
Dora Martins Teixeira ◽  
Manuel Mota
Keyword(s):  
Chemical Properties ◽  
Carbon Chain ◽  
Bursaphelenchus Xylophilus ◽  
Aliphatic Alcohols ◽  
Carbon Chain Length ◽  
Pinewood Nematode ◽  
Medium Carbon ◽  
Highly Active ◽  
Volatile Allelochemicals ◽  
Resin Canals

The pinewood nematode (PWN), Bursaphelenchus xylophilus, induces shoot yellowing and wilting by injuring pine vascular tissues and resin canals. In Asia, it has devastated wide forests of susceptible pine with drastic ecological, economic and cultural repercussions. In 1999, it reached Europe (Portugal) and despite the actions of the authorities, it rapidly advanced to the border areas of Spain, threatening other European pine forests. Chemical control has been used in Asia with remarkable success, yet most nematicides are dangerous to human health and the environment. Natural volatile allelochemicals (VA) and derivatives are sustainable alternatives, providing many advantages to commercial nematicides. The present work summarizes available bibliographic information on VAs with activity against the PWN and reviews the chemical properties leading to nematoxicity. Published works have reported over 250 VAs in direct contact assays. Compounds highly active against the PWN belong to monoterpenoid, phenylpropanoid and aliphatic alcohols; aldehydes, ketones, carboxylic acids, esters and sulphide groups. The presence of highly electronegative elements in these structures appears to increase activity. Trisulphides, coumarins, medium carbon chain length aliphatic alcohols and derivatives comprise the top five most active allelochemicals. An indication of their mechanisms of action can be obtained from studying the reported structure–activity relationships.

scholarly journals Effects of vegetation and topography on biomass patterns post-pinewood nematode disturbance in forest landscapes of southern Jiangxi Province, China

2021 ◽  
Author(s):  
Zhibin Fang ◽  
Zhiwei Wu ◽  
Shitao Lin ◽  
Qiang Liu
Keyword(s):  
Vegetation Type ◽  
Forest Biomass ◽  
Research Area ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Vegetation Coverage ◽  
Jiangxi Province ◽  
Marginal Effect ◽  
Pinewood Nematode ◽  
Biomass Loss

Abstract Background: Assessing changes in forest ecosystems, especially forest biomass changes that occur due to disturbances, is essential for improving global carbon estimates.Bursaphelenchus xylophilus is an important pest that harms Pinus thunbergii forests, causing a large number of pine trees to wither and resulting in great losses in Pinus thunbergii forest biomass. Studying the factors affecting P. thunbergii) biomass losses caused by Bursaphelenchus xylophilus is of great significance in research on forest ecosystem health and climate change. In this study, taking Nankang District, Ganzhou City, Jiangxi Province as the research area, based on field survey data combined with a random forest model, the relative importance of influencing factors on the biomass loss of P. thunbergii due to the Bursaphelenchus xylophilus-caused disease was analyzed.Results: The results revealed the following conclusions: (1) topographic and slope conditions significantly affected the P. thunbergii) biomass losses caused by the Bursaphelenchus xylophilus-related disease; (2) the two studied stand factors, vegetation type and vegetation coverage, had little effect on the P. thunbergii) biomass losses caused by Bursaphelenchus xylophilus; and (3) the marginal effect diagram showed that the elevation and slope were obviously related to biomass loss; biomass loss was positively related to elevation and negatively related to slope.Conclusions: Our study demonstrated that topographical factors dominantly affect the spread of the Bursaphelenchus xylophilus-caused disease, in turn causing large P. thunbergii forest biomass losses. Therefore, topographic factors affect the prevention and control of the disease caused by Bursaphelenchus xylophilus.

scholarly journals Pathogenicity of selected isolates of the quarantine pinewood nematode Bursaphelenchus xylophilus to Scots pine (Pinus sylvestris L.)

2015 ◽  
Vol 55 (4) ◽  
pp. 378-382 ◽  
Author(s):  
Anna Filipiak
Keyword(s):  
Pinus Sylvestris ◽  
Control Plant ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Plant Mortality ◽  
Disease Symptoms ◽  
Pine Seedlings ◽  
Nematode Virulence ◽  
Different Parts

Abstract The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease (PWD). This nematode is considered to be an indigenous to North America and was introduced to Japan in the late 19th century. Subsequently, it has spread throughout Japan and in many other countries, China, Taiwan, and South Korea. In 1999, B. xylophilus was discovered in Portugal, and in 2008 in Spain. So far the studies have revealed that the pathogenicity of B. xylophilus varies between different isolates. The conducted study compared the pathogenicity of five isolates of B. xylophilus, originating from different parts of Japan, to 3-year-old Pinus sylvestris, and their ability to reproduce in the seedlings. The results revealed diverse virulence of B. xylophilus resulting in plant mortality. Three isolates S10, Ka4, and T4 caused 100% mortality of plants within three months while at the same time, the other two isolates, C14-5 and OKD-1 did not cause any disease symptoms on plants. After seven months, some dieback occurred on two seedlings, but similar symptoms were also found on the control plant. Moreover, a significant positive correlation was found between nematode virulence and the number of nematodes reproducing on pine seedlings.

scholarly journals Effects of Temperature Factors on Resistance against Pine Wood Nematodes in Pinus thunbergii, Based on Multiple Location Sites Nematode Inoculation Tests

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 922
Author(s):  
Taiichi Iki ◽  
Koji Matsunaga ◽  
Tomonori Hirao ◽  
Mineko Ohira ◽  
Taro Yamanobe ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Similar Rate ◽  
Bursaphelenchus Xylophilus ◽  
Pinus Thunbergii ◽  
Pinewood Nematode ◽  
Resistance Level ◽  
Japanese Archipelago ◽  
Effects Of Temperature ◽  
The Relationship ◽  
Temperature Factors

Pine wilt disease (PWD) caused by the pinewood nematode (PWN) (Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle) is a worldwide issue. Infection is considered to be promoted mainly by the increased air temperature, but it is important to investigate whether the effect of high temperature similarly influences the different ranks of resistant clone. In the present study, we conducted PWN inoculation tests using six common open-pollinated families of resistant Pinus thunbergii Parl. The tests were conducted at nurseries of five test sites across Japanese archipelago between 2015 and 2017. Our analysis focused specifically on temperature. Firstly, we examined the effects of test sites, inoculation year, and their interaction on unaffected seedling rate and found that the unaffected seedling rate of all tested pine families decreased as the cumulative temperature increased. We found that the unaffected seedling rate decreased as the cumulative temperature increased for all tested pine families. In general, higher cumulative temperatures were required for having an effect on the unaffected seedling rates of higher PWN-resistant families. Typically, early cumulative temperatures, i.e., 19 days after inoculation, had the greatest effect on the unaffected seedling rates of PWN-resistant pines. However, the relationship between cumulative temperature and predicted unaffected seedling rate follow similar rate for all families. Thus, the order of resistance level is maintained in terms of the cumulative temperature required for having an effect.

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