In vivo infection of Bursaphelenchus xylophilus by the fungus Esteya vermicola

2020 ◽  
Vol 76 (8) ◽  
pp. 2854-2864
Author(s):  
Hai‐Hua Wang ◽  
Yun‐Bo Wang ◽  
Can Yin ◽  
Jie Gao ◽  
Ran Tao ◽  
...  
2000 ◽  
Vol 55 (3-4) ◽  
pp. 295-299 ◽  
Author(s):  
Yohannes Alen ◽  
Shuhei Nakajima ◽  
Teruhiko Nitoda ◽  
Naomichi Baba ◽  
Hiroshi Kanzaki ◽  
...  

Abstract Sixty five methanolic extracts of Sumatran rainforest plants representing 63 species of 21 families were assayed in vivo for antinematodal activity against Bursaphelenchus xylophilus using our cotton ball-fungal mat method. Extracts of 27 plants species from 14 families exhibited antinematodal activity, while 37 species were inactive. Among them, three extracts of Bischofia javanica, Knema hookeriana and Areca catechu exhibited very strong activity at minimum effective dose (MED ) of 0.7 mg/cotton ball (mg/bl.). Eight extracts from Allamanda cathartica, Ervatamia corymbosa, Hoya diversifolia, Bischofia javanica, Derris malacensis, Melastoma melabathricum, Ophiorriza konsteleary and Brucea sumatrana also showed strong activity (MED, 5 mg/bl.).


2011 ◽  
Vol 57 (10) ◽  
pp. 838-843 ◽  
Author(s):  
Zhen Wang ◽  
Chun Yan Wang ◽  
Li Juan Gu ◽  
Yun Bo Wang ◽  
Yong An Zhang ◽  
...  

Esteya vermicola , an endoparasitic fungus of pinewood nematode, exhibits great potential as a biological agent against nematodes. In this study to enhance the sporulation, predacity, and environmental resistance of E. vermicola, various nitrogen sources, such as glycine, l-leucine, and ammonium nitrate, were tested. The supplement of glycine and l-leucine had a significant influence on the growth rate of the colony, enhancing colony dry mass by 5-fold more than did ammonium nitrate or the control. Of the nitrogen sources tested, ammonium nitrate and l-leucine promoted sporulation, yielding more than 6 × 106 CFU/g, while glycine enhanced the proportion of lunate spores. Meanwhile, the supplement of nitrogen sources had a significant influence on adhesive rate and mortality rate against Bursaphelenchus xylophilus . Moreover, the supplement of glycine enhanced the survival rate against heat stress by more than 3-fold that of l-leucine, ammonium nitrate, and control. The spores produced in media amended with glycine, l-leucine, and ammonium nitrate had slightly but not significantly higher UV resistance and drought resistance than spores produced without nitrogen sources. These results suggested that the addition of glycine resulted in the production of E. vermicola conidia with increased predacity and resistance to environmental stress that may be more suitable for control of pine wilt disease.


2020 ◽  
Author(s):  
Hai-Hua Wang ◽  
Can Yin ◽  
Jie Gao ◽  
Ran Tao ◽  
Piao-Piao Dai ◽  
...  

AbstractPine wilt disease (PWD) caused by the nematode Bursaphelenchus xylophilus is a serious problem on pines, and there is currently no effective control strategy for this disease. Although the endoparasitic fungus Esteya vermicola showed great effectiveness in controlling pine wilt disease, the colonization patterns of the host pine tree xylem by this fungus are unknown. To investigate the colonization patterns of pine xylem by this fungus, the species Pinus koraiensis grown in a greenhouse was used as an experimental host tree. The fungal colonization of healthy and wilting pine trees by E. vermicola was quantified using PCR with a TaqMan probe, and a green fluorescence protein (GFP) transformant was used for visualization. The results reported a specific infection approach used by E. vermicola to infect B. xylophilus and specialized fungal parasitic cells in PWN infection. In addition, the inoculated blastospores of E. vermicola germinated and grew inside of healthy pine xylem, although the growth rate was slow. Moreover, E. vermicola extended into the pine xylem following spray inoculation of wounded pine seedling stems, and a significant increase in fungal quantity was observed in response to B. xylophilus invasion. An accelerated extension of E. vermicola colonization was shown in PWN-infected wilting pine trees, due to the immigration of fungal-infected PWNs. Our results provide helpful knowledge about the extension rate of this fungus in healthy and wilting PWN-susceptible pine trees in the biological control of PWD and will contribute to the development of a management method for PWD control in the field.Author summaryPine wilt disease, caused by Bursaphelenchus xylophilus, has infected most pine forests in Asian and European forests and led to enormous losses of forest ecosystem and economy. Esteya vermicola is a bio-control fungus against pinewood nematode, showed excellent control efficient to pine wilt disease in both of greenhouse experiments and field tests. Although this bio-control agent was well known for the management of pine wilt disease, the infection mechanism of fungal infection and colonization of host pine tree are less understand. Here, we use GFP-tagged mutant to investigate the fungal infection to pinewood nematode; additionally, the temporal and spatial dynamics of E. vermicola colonize to pine tree were determined by the TaqMan real-time PCR quantification, as well as the response to pinewood nematode invasion. We found a specific infection approach used by E. vermicola to infect B. xylophilus and specialized fungal parasitic cells in PWN infection. In addition, the fungal germination and extension inside of pine tree xylem after inoculation were revealed. In addition, the quantity of E. vermicola increased as response to pinewood nematode invasion was reported. Our study provides two novel technologies for the visualization and detection of E. vermicola for the future investigations of fungal colonization and its parasitism against pinewood nematode, and the mechanisms of the bio-control process.


BioControl ◽  
2010 ◽  
Vol 56 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Chun Yan Wang ◽  
Zhe Ming Fang ◽  
Zhen Wang ◽  
Dong Liang Zhang ◽  
Li Juan Gu ◽  
...  

Nematology ◽  
2015 ◽  
Vol 17 (9) ◽  
pp. 1071-1080 ◽  
Author(s):  
Xuan Wang ◽  
Tinglong Guan ◽  
Long Zhang ◽  
Hongmei Li

A serine protease geneEvspwas cloned from the nematophagous fungusEsteya vermicolawith strong virulence againstBursaphelenchus xylophilus. The full-length cDNA ofEvspcontains 2280 nucleotides with a 1656 bp ORF encoding a protein with 551 amino acids. The genomicEvspincludes two exons (396 bp and 1260 bp) separated by an intron (207 bp). There is only one copy ofEvspgene in the fungal genome. The deduced amino acids sequences ofEvspshowed highly homology with the catalytic domains in subtilisin serine proteases. Phylogenetic analyses based on the protein sequences revealed thatE. vermicolais separated from nematode-trapping fungi but close to other nematophagous and entomopathogenic fungi. The recombinant serine protease rEvsp was induced inEscherichia coliwith expression vector pET28a(+). The tests of protease and nematicidal activities for the purified and refolded rEvsp indicated it is possibly involved in the fungal infection process againstB. xylophilus.


Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3634 ◽  
Author(s):  
Deok Jea Cha ◽  
Junheon Kim ◽  
Dong Soo Kim

Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, is a serious forest pest, causing enormous economic losses in pine trees in Korea, China, Japan, and countries in Western Europe. To prevent pine wilt disease (PWD), trunk injection with nematicide is performed in Korea. Although these nematicidal agents are quite efficient, the development of new nematicidal agents is needed to prevent pesticide resistance and reduce pest management costs. The aim of this study was to investigate nematicidal activities of pure naphthoquinones (NTQs)–1,4-NTQ, juglone, and plumbagin—against B. xylophilus via in vitro and semi-in vivo assays to identify new candidate agents for trunk injection. Estimated LC50 values (48 h exposure) were 100.0 ppm, 57.0 ppm, and 104.0 ppm for 1,4-NTQ, juglone, and plumbagin, respectively. In the semi-in vivo assay on pine bolt of the Japanese black pine, Pinus thunbergii, the population of inoculated B. xylophilus was significantly decreased at two weeks after treatment with juglone when compared with the effects of treatment with 1,4-NTQ and plumbagin. We also observed that naphthoquinones could generate reactive oxygen species, which presumably indicated that naphthoquinones caused significant oxidative stress in B. xylophilus. The findings of this study suggest the nematicidal potential of naphthoquinones and their possible use in further in vivo assays to test their nematicidal efficacy against B. xylophilus when injected through trunk injection.


2013 ◽  
Vol 29 (12) ◽  
pp. 2429-2436 ◽  
Author(s):  
Yun-Bo Wang ◽  
Zhi-Hong Yang ◽  
Jiao-Jiao Yu ◽  
Yong-An Zhang ◽  
Jian-Jie Xue ◽  
...  

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1000
Author(s):  
Jungwook Park ◽  
Hee Won Jeon ◽  
Hyejung Jung ◽  
Hyun-Hee Lee ◽  
Junheon Kim ◽  
...  

The pinewood nematode (PWN) Bursaphelenchus xylophilus causes pine wilt disease, which results in substantial economic and environmental losses across pine forests worldwide. Although systemic acquired resistance (SAR) is effective in controlling PWN, the detailed mechanisms underlying the resistance to PWN are unclear. Here, we treated pine samples with two SAR elicitors, acibenzolar-S-methyl (ASM) and methyl salicylic acid (MeSA) and constructed an in vivo transcriptome of PWN-infected pines under SAR conditions. A total of 252 million clean reads were obtained and mapped onto the reference genome. Compared with untreated pines, 1091 and 1139 genes were differentially upregulated following the ASM and MeSA treatments, respectively. Among these, 650 genes showed co-expression patterns in response to both SAR elicitors. Analysis of these patterns indicated a functional linkage among photorespiration, peroxisome, and glycine metabolism, which may play a protective role against PWN infection-induced oxidative stress. Further, the biosynthesis of flavonoids, known to directly control parasitic nematodes, was commonly upregulated under SAR conditions. The ASM- and MeSA-specific expression patterns revealed functional branches for myricetin and quercetin production in flavonol biosynthesis. This study will enhance the understanding of the dynamic interactions between pine hosts and PWN under SAR conditions.


2021 ◽  
Author(s):  
Min-Kyoung Kang ◽  
Jong-Hoon Kim ◽  
Min-Jiao Liu ◽  
Chun-Zhi Jin ◽  
Dong-Jin Park ◽  
...  

Abstract Endophytic bacteria, a rich source of bioactive secondary metabolites, are ideal candidates for environmentally benign agents. In this study, an endophytic strain, Streptomyces sp. AE170020, was isolated and selected for the purification of nematicidal substances based on its high nematicidal activity. Two highly active components, aureothin and alloaureothin, were identified, and their chemical structures were determined using spectroscopic analysis. Both compounds suppressed the growth, reproduction, and behavior of Bursaphelenchus xylophilus. In in vivo experiments, the extracts of strain Streptomyces sp. AE170020 effectively suppressed the development of pine wilt disease in four-year-old plants of Pinus densiflora. The potency of secondary metabolites isolated from endophytic strains suggests applications in controlling Bursaphelenchus xylophilus and opens an avenue for further research on exploring bioactive substances against the pine wood nematode.


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