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 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.

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.

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.

scholarly journals Bxy‐fuca encoding α‐L‐fucosidase plays crucial roles in development and reproduction of the pathogenic pinewood nematode, Bursaphelenchus xylophilus

2019 ◽  
Vol 76 (1) ◽  
pp. 205-214 ◽  
Author(s):  
Jia Tang ◽  
Ruoqing Ma ◽  
Najie Zhu ◽  
Kai Guo ◽  
Yiqing Guo ◽  
...  
Keyword(s):  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode

scholarly journals Optimization of Rocky Desertification Classification Model Based on Vegetation Type and Seasonal Characteristic

2021 ◽  
Vol 13 (15) ◽  
pp. 2935
Author(s):  
Chunhua Qian ◽  
Hequn Qiang ◽  
Feng Wang ◽  
Mingyang Li
Keyword(s):  
Learning Algorithm ◽  
Vegetation Type ◽  
Research Area ◽  
Classification Model ◽  
Guizhou Province ◽  
Model Accuracy ◽  
Spatiotemporal Evolution ◽  
Rocky Desertification ◽  
The North ◽  
Svm Model

Building a high-precision, stable, and universal automatic extraction model of the rocky desertification information is the premise for exploring the spatiotemporal evolution of rocky desertification. Taking Guizhou province as the research area and based on MODIS and continuous forest inventory data in China, we used a machine learning algorithm to build a rocky desertification model with bedrock exposure rate, temperature difference, humidity, and other characteristic factors and considered improving the model accuracy from the spatial and temporal dimensions. The results showed the following: (1) The supervised classification method was used to build a rocky desertification model, and the logical model, RF model, and SVM model were constructed separately. The accuracies of the models were 73.8%, 78.2%, and 80.6%, respectively, and the kappa coefficients were 0.61, 0.672, and 0.707, respectively. SVM performed the best. (2) Vegetation types and vegetation seasonal phases are closely related to rocky desertification. After combining them, the model accuracy and kappa coefficient improved to 91.1% and 0.861. (3) The spatial distribution characteristics of rocky desertification in Guizhou are obvious, showing a pattern of being heavy in the west, light in the east, heavy in the south, and light in the north. Rocky desertification has continuously increased from 2001 to 2019. In conclusion, combining the vertical spatial structure of vegetation and the differences in seasonal phase is an effective method to improve the modeling accuracy of rocky desertification, and the SVM model has the highest rocky desertification classification accuracy. The research results provide data support for exploring the spatiotemporal evolution pattern of rocky desertification in Guizhou.

scholarly journals Genetic characteristics of Bursaphelenchus xylophilus third-stage dispersal juveniles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qiaoli Chen ◽  
Ruizhi Zhang ◽  
Danlei Li ◽  
Feng Wang
Keyword(s):  
Fat Metabolism ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Genetic Characteristics ◽  
Highest Weight ◽  
Homologous Genes ◽  
Third Stage ◽  
Highly Correlated ◽  
Oil Red O Staining ◽  
Oil Red O

AbstractThe third-stage dispersal juvenile (DJ3) of pinewood nematode (PWN) is highly associated with low-temperature survival and spread of the nematode. Oil-Red-O staining showed that its lipid content was significantly higher compared with other PWN stages. Weighted gene coexpression network analysis identified that genes in the pink module were highly related to DJ3 induced in the laboratory (DJ3-lab). These genes were arranged according to their gene significance (GS) to DJ3-lab. Of the top 30 genes with the highest GS, seven were found to be highly homologous to the cysteine protease family cathepsin 1 (CATH1). The top 30 genes with the highest weight value to each of the seven genes in the pink module were selected, and finally 35 genes were obtained. Between these seven CATH1 homologous genes and their 35 highly related genes, 15 were related to fat metabolism or autophagy. These autophagy-related genes were also found to be highly correlated with other genes in the pink module, suggesting that autophagy might be involved in the mechanism of longevity in DJ3 and the formation of DJ3 by regulating genes related to fat metabolism.

scholarly journals Chitosan increases Pinus pinaster tolerance to the pinewood nematode (Bursaphelenchus xylophilus) by promoting plant antioxidative metabolism

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Nunes da Silva ◽  
Carla S. Santos ◽  
Ana Cruz ◽  
Adrián López-Villamor ◽  
Marta W. Vasconcelos
Keyword(s):  
Phenolic Compounds ◽  
Pinus Pinaster ◽  
Plant Defence ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Nematode Population ◽  
Post Inoculation ◽  
Pinewood Nematode ◽  
Plant Tolerance ◽  
The Moment

AbstractThe pine wilt disease (PWD), for which no effective treatment is available at the moment, is a constant threat to Pinus spp. plantations worldwide, being responsible for significant economic and environmental losses every year. It has been demonstrated that elicitation with chitosan increases plant tolerance to the pinewood nematode (PWN) Bursaphelenchus xylophilus, the causal agent of the PWD, but the biochemical and genetic aspects underlying this response have not been explored. To understand the influence of chitosan in Pinus pinaster tolerance against PWN, a low-molecular-weight (327 kDa) chitosan was applied to mock- and PWN-inoculated plants. Nematode population, malondialdehyde (MDA), catalase, carotenoids, anthocyanins, phenolic compounds, lignin and gene expression related to oxidative stress (thioredoxin 1, TRX) and plant defence (defensin, DEF, and a-farnesene synthase, AFS), were analysed at 1, 7, 14, 21 and 28 days post-inoculation (dpi). At 28 dpi, PWN-infected plants elicited with chitosan showed a sixfold lower nematode population when compared to non-elicited plants. Higher levels of MDA, catalase, carotenoids, anthocyanins, phenolic compounds, and lignin were detected in chitosan-elicited plants following infection. The expression levels of DEF gene were higher in elicited plants, while TRX and AFS expression was lower, possibly due to the disease containment-effect of chitosan. Combined, we conclude that chitosan induces pine defences against PWD via modulation of metabolic and transcriptomic mechanisms related with plant antioxidant system.

scholarly journals In Silico Screening of Agonist and Antagonist Natural Compounds from Reported Essential Oils against Bursaphelenchus xylophilus

2020 ◽  
Vol 3 (1) ◽  
pp. 31
Author(s):  
Jorge M. S. Faria ◽  
Ana Margarida Rodrigues ◽  
Pedro Barbosa ◽  
Manuel Mota
Keyword(s):  
Essential Oils ◽  
Pine Wilt Disease ◽  
Natural Compounds ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Highly Active ◽  
Bibliographic Data ◽  
Agonist And Antagonist ◽  
Containment Strategy ◽  
Detailed Chemical

Chemical control has been the most effective and reliable containment strategy in integrated pest management of pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Yet, large spectrum nematicides can be dangerous to human health and the environment. Essential oils (EOs) are safer sustainable alternatives, being composed of highly active natural compounds. A survey of bibliographic data on the detailed chemical composition and activity of the EOs used against the PWN allowed pinpointing monoterpenes as the main source of structures with agonist or antagonist properties. Transversal EO data treatment can identify potential highly active anti-PWN compounds.

Sign in / Sign up

Export Citation Format

Share Document