Masson pine characteristics were analyzed in five sample plots in Zhejiang Province, China. Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle （pine wood nematode, PWN） carried by Monochamus alternatus predomin...Masson pine characteristics were analyzed in five sample plots in Zhejiang Province, China. Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle （pine wood nematode, PWN） carried by Monochamus alternatus predominately attacked Masson pines in the lower diameter classes. Among the 10 tree characteristics examined, mean crown width, percentage of bole with crown, 5-year cumulative diameter growth, and resin amount showed significant variation between successfully attacked and unattacked trees. The attacked trees had a lower percentage of the bole covered with tree crown, lower crown width, lower radial growth in the last 5 years, and produced less induced resinosis than unattacked trees. Results allowed for effective ranking of the pine forest based on individual tree resistance to PWN. This index of resistance should be considered throughout the development of an ＂Evaluation Criterion and Indicator System＂. The preceding ranking can be used to evaluate the resistance and resiliency of the pine forest ecosystem to PWN＇s invasion, which is similar to Pest Risk Analysis （PRA）.展开更多
Pine wilt disease (PWD), which is caused by pine wood nematodes (PWN), is one of the most serious forest diseases worldwide. To clarify the mechanism of resistance to PWD, we compared metabolites from resistant and su...Pine wilt disease (PWD), which is caused by pine wood nematodes (PWN), is one of the most serious forest diseases worldwide. To clarify the mechanism of resistance to PWD, we compared metabolites from resistant and susceptible Japanese black pine (Pinus thunbergii) families after inoculation with PWN. After 2 weeks to 1 month post inoculation, the number of PWN dramatically increased in susceptible plants, but not in resistant plants. At this PWN-proliferation phase, ethyl acetate soluble fractions extracted from PWN-inoculated plants were analyzed by gas chromatogramphy-mass spectrometry (GC-MS). Although most compounds were qualitatively and quantitatively similar between resistant and susceptible plants, resistant plants accumulated 2.0-fold more linoleic acid (LA) than susceptible plants. On the other hand, benzoic acid (BA) was barely detected in resistant plants, but it accumulated in susceptible plants as the number of PWN increased. Susceptible plants contained greater levels of the nematicidal compounds pinosylvin and pinosylvin monomethyl ether, compared with resistant plants. These results suggested that LA is involved in the resistance reaction against PWN-proliferation, and that BA could be a good biomarker for PWD.展开更多
In our previous screening of the transcriptome of the causal agent of the devastating pine wilt disease,pine wood nematode(PWN,Bursaphelenchus xylophilus),after treatment with the nematicide fomepizole,Surfeit locus g...In our previous screening of the transcriptome of the causal agent of the devastating pine wilt disease,pine wood nematode(PWN,Bursaphelenchus xylophilus),after treatment with the nematicide fomepizole,Surfeit locus gene sft-4,which encodes a regulatory factor,was found to be downregulated.In situ hybridization results showed that the sft-4 was continuously expressed from egg to adult and was especially high in the reproductive system.Here in a study of the effect of RNA interference(RNAi)of sft-4 and recombinant SFT-4 on PWN activity,treatment with sft-4 dsRNA inhibited feeding,reproduction,oviposition and egg hatching of PWN with the greatest inhibition on reproduction and oviposition,whereas recombinant SFT-4 had the opposite effect.In addition,RNAi of sft-4 changed the female–male ratio and lifespan of PWN.In bioassays of PWNs,with RNAi of sft-4 on seedlings and 2-year-old Pinus thunbergii trees,none of the treated plants developed symp-toms during the monitoring period,indicating that virulence of PWNs was either significantly weakened.These results indicate that the influence of sft-4 on PWN pathogenicity may be mainly through regulating reproductive function of PWN and its lifespan.展开更多
The pinewood nematode(PWN)Bursaphelenchus xylophilus is a forestry quarantine pest and causes an extremely dangerous forest disease that is spreading worldwide.Due to the complex pathogenic factors of pine wood nemato...The pinewood nematode(PWN)Bursaphelenchus xylophilus is a forestry quarantine pest and causes an extremely dangerous forest disease that is spreading worldwide.Due to the complex pathogenic factors of pine wood nematode disease,the pathogenesis is still unknown.B.xylophilus ultimately invades a host and causes death.However,little is known about the defence-regulating process of host pine after infection by B.xylophilus at the molecular level.Therefore,we wanted to understand how Pinus massoniana regulates its response to invasion by B.xylophilus.P.massoniana were artificially inoculated with B.xylophilus solution,while those without B.xylophilus solution were used as controls.P.massoniana inoculated with B.xylophilus solution for 0 h,6 h,24 h,and 120 h was subjected to highthroughput sequencing to obtain transcriptome data.At various time points(0 h,6 h,24 h,120 h),gene transcription was measured in P.massoniana inoculated with PWN.At different time points,P.massoniana gene transcription differed significantly,with a response to early invasion by PWN.According to Gene Ontology(GO)classification and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis,P.massoniana response to PWN invasion involves a wide range of genes,including plant hormone signal transformation,flavonoid biosynthesis,amino sugar and nucleoside sugar metabolism,and MAPK signalling pathways.Among them,inoculation for 120 hours had the greatest impact on differential genes.Subsequently,weighted gene coexpression network analysis(WGCNA)was used to analyse transcriptional regulation of P.massoniana after PWN infection.The results showed that the core gene module of P.massoniana responding to PWN was“MEmagenta”,enriched in oxidative phosphorylation,amino sugar and nucleotide sugar metabolism,and the MAPK signalling pathway.MYB family transcription factors with the highest number of changes between infected and healthy pine trees accounted for 20.4% of the total differentially expressed transcription factors.To conclude,this study con展开更多
To accelerate the breeding and selection of Pinus densiflora Siebold and Zucc. resistance to pine wilt disease, a micropropagation system was established and nematode resistance evaluated in vitro. Cotyledon-hypocotyl...To accelerate the breeding and selection of Pinus densiflora Siebold and Zucc. resistance to pine wilt disease, a micropropagation system was established and nematode resistance evaluated in vitro. Cotyledon-hypocotyl explants from 28-day-old seedlings were first cultured on Gresshoff and Doy medium supplemented with 4.0 mg L^(-1) 6-benzyladenine and 0.2 mg L^(-1) a-naphthaleneacetic acid(NAA) to stimulate the formation of buds. Induced buds were subsequently subcultured on Gupta and Durzan medium supplemented with 0.1%(w/v)activated charcoal for elongation. Stem sections derived from shoots were used as explants for the further multiplication. Roots were formed from shoots transferred to woody plant medium containing 0.2 mg L^(-1) NAA for4 weeks. The nematode resistance test showed that symptoms in micropropagated shoots after infection with pine wood nematode(PWN) were similar to those in plants infected in the field. The wilting rate varied from 20 to100% among different clones 18 days after inoculation.The most susceptible clone was Clone 6-4 with a 100%wilting rate, while Clone 8-4 showed a relatively high resistance with a 20% wilting rate. The number of nematodes recovered from Clone 8-4 shoots was significantly lower(P = 0.05) than from Clones 5-10 and 16-4. This work contributes to the breeding of PWN resistance in P.densiflora.展开更多
The pine sawyer beetle, Monochamus alternatus, is regarded as a notorious for- est pest in Asia, vectoring an invasive pathogenic nematode, Bursaphelenchus xylophilus, which is known to cause pine wilt disease. Howeve...The pine sawyer beetle, Monochamus alternatus, is regarded as a notorious for- est pest in Asia, vectoring an invasive pathogenic nematode, Bursaphelenchus xylophilus, which is known to cause pine wilt disease. However, little sequence information is available for this vector beetle. This hampered the research on its immune system. Based on the transcriptome of M. alternatus, we have identified and characterized 194 immunity-related genes in M. alternatus, and compared them with homologues molecules from other species known to exhibit immune responses against invading microbes. The lower number of puta- tive immunity-related genes in M. alternatus were attributed to fewer C-type lectin, serine protease （SP） and anti-microbial peptide （AMP） genes. Phylogenetic analysis revealed that M. alternatus had a unique recognition gene, galectin3, orthologues of which were not identified in Tribolium castaneum, Drosophila melanogastor, Anopheles gambiae and Apis mellifera. This suggested a lineage-specific gene evolution for coleopteran insects. Our study provides the comprehensive sequence resources of the immunity-related genes ofM. alternatus, presenting valuable information for better understanding of the molecular mechanism of innate immunity processes in M. alternatus against B. xylophilus.展开更多
Pine wilt is a serious and fatal disease in pine forests. It is caused by the pine wood nematode, Bursaphelenchus xylophilus, transmitted by the Japanese saw beetle Monochamus alternatus. Control of this disease depen...Pine wilt is a serious and fatal disease in pine forests. It is caused by the pine wood nematode, Bursaphelenchus xylophilus, transmitted by the Japanese saw beetle Monochamus alternatus. Control of this disease depends on reducing its vector population. The public is demanding environmentally friendly control methods and biological control has become increasingly seen as an impor-tant, safe and effective approach. Through our investigations both in the field and by breeding in our laboratory, a new predator of M. alternatus, Tetrigus lewisi （Coleoptera： Elateridae）, was found for the first time in China. Given our continuous observations, we are assured that the predatory behavior of the elater can be separated into four parts, i.e., foraging and sensing, killing, eating and excre-tion. They always took several hours to eat the preys that have been killed momentarily. We finally found that most of the elaters preferably attacked in the stomach and abdomen of the larva of M. alternatus.展开更多
Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease, which has greatly damaged forests and ecosystems in countries of East Asia and Europe.Bursaphelenchus mucronatus is closely related to B. xylop...Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease, which has greatly damaged forests and ecosystems in countries of East Asia and Europe.Bursaphelenchus mucronatus is closely related to B. xylophilus in morphology and host plant specificity. A longrunning debate has existed regarding whether these two species can successfully produce hybrid offspring. In the present study, we performed in the laboratory, hybridization of two B. xylophilus nematode isolates from China and Japan and three B. mucronatus isolates from China, Japan and France. Nematode isolates of B. xylophilus were successfully crossed with B. mucronatus isolates, and the rate of hybridization was relatively high; however, some hybrid offspring died. Successful hybridization occurred between B. xylophilus and B. mucronatus isolates from China, and 22 generations of hybrids were produced. All F1 hybrids could be backcrossed with their parents and produce offspring. Variation in mucro length among the hybrid offspring and their parents was observed. The hybrid offspring and their parents were inoculated into 3-months-old black pine(Pinus tunbergii) seedlings. Weaker pathogenicity of hybrid offspring was observed compared with that of their parents, and significantly fewer offspring nematodes than parents were reisolated from pines. Therefore, the offspring of B. xylophilus and B. mucronatus may exist in the forest and could influence disease epidemics.展开更多
Pine wilt disease(PWD)is a devastating disease affecting the growth of Pinus massoniana,often leading to withering and death.To reveal the changes involved during disease progression,we investigated the mRNA expressio...Pine wilt disease(PWD)is a devastating disease affecting the growth of Pinus massoniana,often leading to withering and death.To reveal the changes involved during disease progression,we investigated the mRNA expression profile of P.massoniana infested by Bursaphelenchus xylophilus.The infestation resulted in the downregulation of genes involved in interactions with pathogenic pathways such as disease resistance gene,CC-NBS-LRR resistancelike protein,and the gene encoding a putative nematode resistance protein.Increased infestation pressure(number of nematodes inoculated)caused a continuous decline in the gene expression of stem samples.An infestation of P.massoniana also resulted in a pathway enrichment of genes involved in phenylpropanoid metabolism and flavonoid biosynthesis,which in turn reduced the levels of total phenols and total flavonoids.A downregulation of auxin responsive family protein was observed in infested samples,which resulted in a suppression of plant growth.Thus,upon B.xylophilus infestation,a downregulation of genes associated with the recognition of pathogens,PWD resistance,and growth regulation was observed in P.massoniana,together with a decrease in the levels of phytoalexinlike secondary substances,all of which resulted in withering and ultimately death of P.massoniana.展开更多
The invasion of Bursaphelenchus xylophilus （pine wood nematode, PWN） carried by Monochamus alternatus predominately attacks Masson pine （Pinus massoniana） forests and causes great economic losses in China. In this...The invasion of Bursaphelenchus xylophilus （pine wood nematode, PWN） carried by Monochamus alternatus predominately attacks Masson pine （Pinus massoniana） forests and causes great economic losses in China. In this study, we assessed whether the effect of the invasion of PWN is different between island and inland forests. Arthropods were sampled in Fuyang （inland） and Zhoushan （island） counties in Zhejiang Province with sweep netting and light traps at four plots. During two field periods （May to June 2004 and September to October 2005） a total of 21,916 insects, representing 384 species belonging to 99 families and 15 orders, were collected in the sample plots from the island, whereas, from the inland forest a total of 29,262 insects, representing 308 species belonging to 96 families and 13 orders, were found. A hierarchical cluster analysis （HCA） and one-way ANOVA, based on the composition of different arthropod guilds, were performed. The results showed that there was no significant difference in the composition of arthropod communities at the family level between inland and island. But these two habitats had a significant effect on the composition of species, individuals, sub-communities and energy class levels. Statistically, the composition of the two orders, Lepidoptera and Diptera, in the two habitats were significantly different.展开更多
Our research focused on Pinus massoniana information extracted from remote sensing images based on the knowledge detection and decision tree algorithm and established a spatial pattern model, combining quantitative th...Our research focused on Pinus massoniana information extracted from remote sensing images based on the knowledge detection and decision tree algorithm and established a spatial pattern model, combining quantitative theoretical ecology with remote sensing （RS） and geometric information system （GIS） techniques. Applying information extraction methods and a spatial pattern model, we studied P. massoniana spatial patterns changes before and after the invasion by pine wood nematode （Bursaphelenchus xylophilus） in Fuyang and Zhoushan counties, Zhejiang Province, east China. The P. massoniana spatial patterns are clustering, whether the invasion happened or not. But the degree of clustering is different. Our results show good agreement with field data. Applying the results, we analyzed the relationship between spatial patterns and the invasion level. Then we drew the elementary conclusion that there are two kinds of patterns for pine wood nematode to spread： continuous and discontinuous diffusion. This approach can help monitor and evaluate the changes in ecological systems.展开更多
Pine wood nematode （PWN）, Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to im...Pine wood nematode （PWN）, Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion, we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme “Prevention is priority, but integrated with curative techniques and ecological resilience” on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosys-tems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way.展开更多
基金Supported by the State Key Basic Research and Development Plan of China (2002CB111404)the National"948"Item of The Introduction of Prevention+2 种基金Key Management Technology on Invasive Alien Species(2006-4-37)the Key Project for the"Eleventh Five"Year Plan,China(2006BAD08A15)Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT0607)
文摘Masson pine characteristics were analyzed in five sample plots in Zhejiang Province, China. Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle （pine wood nematode, PWN） carried by Monochamus alternatus predominately attacked Masson pines in the lower diameter classes. Among the 10 tree characteristics examined, mean crown width, percentage of bole with crown, 5-year cumulative diameter growth, and resin amount showed significant variation between successfully attacked and unattacked trees. The attacked trees had a lower percentage of the bole covered with tree crown, lower crown width, lower radial growth in the last 5 years, and produced less induced resinosis than unattacked trees. Results allowed for effective ranking of the pine forest based on individual tree resistance to PWN. This index of resistance should be considered throughout the development of an ＂Evaluation Criterion and Indicator System＂. The preceding ranking can be used to evaluate the resistance and resiliency of the pine forest ecosystem to PWN＇s invasion, which is similar to Pest Risk Analysis （PRA）.
文摘Pine wilt disease (PWD), which is caused by pine wood nematodes (PWN), is one of the most serious forest diseases worldwide. To clarify the mechanism of resistance to PWD, we compared metabolites from resistant and susceptible Japanese black pine (Pinus thunbergii) families after inoculation with PWN. After 2 weeks to 1 month post inoculation, the number of PWN dramatically increased in susceptible plants, but not in resistant plants. At this PWN-proliferation phase, ethyl acetate soluble fractions extracted from PWN-inoculated plants were analyzed by gas chromatogramphy-mass spectrometry (GC-MS). Although most compounds were qualitatively and quantitatively similar between resistant and susceptible plants, resistant plants accumulated 2.0-fold more linoleic acid (LA) than susceptible plants. On the other hand, benzoic acid (BA) was barely detected in resistant plants, but it accumulated in susceptible plants as the number of PWN increased. Susceptible plants contained greater levels of the nematicidal compounds pinosylvin and pinosylvin monomethyl ether, compared with resistant plants. These results suggested that LA is involved in the resistance reaction against PWN-proliferation, and that BA could be a good biomarker for PWD.
基金supported by the Shandong Provincial Natural Science Foundation,China(ZR2020MC123)Qingdao Municipal People-benefitting Demonstration Project of Science and Technology,China(23-2-8-cspz-8-nsh).
文摘In our previous screening of the transcriptome of the causal agent of the devastating pine wilt disease,pine wood nematode(PWN,Bursaphelenchus xylophilus),after treatment with the nematicide fomepizole,Surfeit locus gene sft-4,which encodes a regulatory factor,was found to be downregulated.In situ hybridization results showed that the sft-4 was continuously expressed from egg to adult and was especially high in the reproductive system.Here in a study of the effect of RNA interference(RNAi)of sft-4 and recombinant SFT-4 on PWN activity,treatment with sft-4 dsRNA inhibited feeding,reproduction,oviposition and egg hatching of PWN with the greatest inhibition on reproduction and oviposition,whereas recombinant SFT-4 had the opposite effect.In addition,RNAi of sft-4 changed the female–male ratio and lifespan of PWN.In bioassays of PWNs,with RNAi of sft-4 on seedlings and 2-year-old Pinus thunbergii trees,none of the treated plants developed symp-toms during the monitoring period,indicating that virulence of PWNs was either significantly weakened.These results indicate that the influence of sft-4 on PWN pathogenicity may be mainly through regulating reproductive function of PWN and its lifespan.
基金supported by the Fundamental Research Funds of Research Institute of Forest New Technology,CAF(CAFYBB2020SZ008)National Natural Science Foundation of China(32171808).
文摘The pinewood nematode(PWN)Bursaphelenchus xylophilus is a forestry quarantine pest and causes an extremely dangerous forest disease that is spreading worldwide.Due to the complex pathogenic factors of pine wood nematode disease,the pathogenesis is still unknown.B.xylophilus ultimately invades a host and causes death.However,little is known about the defence-regulating process of host pine after infection by B.xylophilus at the molecular level.Therefore,we wanted to understand how Pinus massoniana regulates its response to invasion by B.xylophilus.P.massoniana were artificially inoculated with B.xylophilus solution,while those without B.xylophilus solution were used as controls.P.massoniana inoculated with B.xylophilus solution for 0 h,6 h,24 h,and 120 h was subjected to highthroughput sequencing to obtain transcriptome data.At various time points(0 h,6 h,24 h,120 h),gene transcription was measured in P.massoniana inoculated with PWN.At different time points,P.massoniana gene transcription differed significantly,with a response to early invasion by PWN.According to Gene Ontology(GO)classification and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis,P.massoniana response to PWN invasion involves a wide range of genes,including plant hormone signal transformation,flavonoid biosynthesis,amino sugar and nucleoside sugar metabolism,and MAPK signalling pathways.Among them,inoculation for 120 hours had the greatest impact on differential genes.Subsequently,weighted gene coexpression network analysis(WGCNA)was used to analyse transcriptional regulation of P.massoniana after PWN infection.The results showed that the core gene module of P.massoniana responding to PWN was“MEmagenta”,enriched in oxidative phosphorylation,amino sugar and nucleotide sugar metabolism,and the MAPK signalling pathway.MYB family transcription factors with the highest number of changes between infected and healthy pine trees accounted for 20.4% of the total differentially expressed transcription factors.To conclude,this study con
基金funded by the Special Research Program for Forestry Sectors Beneficial to Public,State Forestry Administration,China(Grant No.201204501)the Science and Technology Support Program of Jiangsu Province(BE2014405)+1 种基金the Key University Science Research Project of Jiangsu Province(15KJA220003)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘To accelerate the breeding and selection of Pinus densiflora Siebold and Zucc. resistance to pine wilt disease, a micropropagation system was established and nematode resistance evaluated in vitro. Cotyledon-hypocotyl explants from 28-day-old seedlings were first cultured on Gresshoff and Doy medium supplemented with 4.0 mg L^(-1) 6-benzyladenine and 0.2 mg L^(-1) a-naphthaleneacetic acid(NAA) to stimulate the formation of buds. Induced buds were subsequently subcultured on Gupta and Durzan medium supplemented with 0.1%(w/v)activated charcoal for elongation. Stem sections derived from shoots were used as explants for the further multiplication. Roots were formed from shoots transferred to woody plant medium containing 0.2 mg L^(-1) NAA for4 weeks. The nematode resistance test showed that symptoms in micropropagated shoots after infection with pine wood nematode(PWN) were similar to those in plants infected in the field. The wilting rate varied from 20 to100% among different clones 18 days after inoculation.The most susceptible clone was Clone 6-4 with a 100%wilting rate, while Clone 8-4 showed a relatively high resistance with a 20% wilting rate. The number of nematodes recovered from Clone 8-4 shoots was significantly lower(P = 0.05) than from Clones 5-10 and 16-4. This work contributes to the breeding of PWN resistance in P.densiflora.
文摘The pine sawyer beetle, Monochamus alternatus, is regarded as a notorious for- est pest in Asia, vectoring an invasive pathogenic nematode, Bursaphelenchus xylophilus, which is known to cause pine wilt disease. However, little sequence information is available for this vector beetle. This hampered the research on its immune system. Based on the transcriptome of M. alternatus, we have identified and characterized 194 immunity-related genes in M. alternatus, and compared them with homologues molecules from other species known to exhibit immune responses against invading microbes. The lower number of puta- tive immunity-related genes in M. alternatus were attributed to fewer C-type lectin, serine protease （SP） and anti-microbial peptide （AMP） genes. Phylogenetic analysis revealed that M. alternatus had a unique recognition gene, galectin3, orthologues of which were not identified in Tribolium castaneum, Drosophila melanogastor, Anopheles gambiae and Apis mellifera. This suggested a lineage-specific gene evolution for coleopteran insects. Our study provides the comprehensive sequence resources of the immunity-related genes ofM. alternatus, presenting valuable information for better understanding of the molecular mechanism of innate immunity processes in M. alternatus against B. xylophilus.
文摘Pine wilt is a serious and fatal disease in pine forests. It is caused by the pine wood nematode, Bursaphelenchus xylophilus, transmitted by the Japanese saw beetle Monochamus alternatus. Control of this disease depends on reducing its vector population. The public is demanding environmentally friendly control methods and biological control has become increasingly seen as an impor-tant, safe and effective approach. Through our investigations both in the field and by breeding in our laboratory, a new predator of M. alternatus, Tetrigus lewisi （Coleoptera： Elateridae）, was found for the first time in China. Given our continuous observations, we are assured that the predatory behavior of the elater can be separated into four parts, i.e., foraging and sensing, killing, eating and excre-tion. They always took several hours to eat the preys that have been killed momentarily. We finally found that most of the elaters preferably attacked in the stomach and abdomen of the larva of M. alternatus.
基金supported by the special research program for non-profit forestry of the State Forestry Administration(201204501)National Nature Science Foundation of China(31170600)funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease, which has greatly damaged forests and ecosystems in countries of East Asia and Europe.Bursaphelenchus mucronatus is closely related to B. xylophilus in morphology and host plant specificity. A longrunning debate has existed regarding whether these two species can successfully produce hybrid offspring. In the present study, we performed in the laboratory, hybridization of two B. xylophilus nematode isolates from China and Japan and three B. mucronatus isolates from China, Japan and France. Nematode isolates of B. xylophilus were successfully crossed with B. mucronatus isolates, and the rate of hybridization was relatively high; however, some hybrid offspring died. Successful hybridization occurred between B. xylophilus and B. mucronatus isolates from China, and 22 generations of hybrids were produced. All F1 hybrids could be backcrossed with their parents and produce offspring. Variation in mucro length among the hybrid offspring and their parents was observed. The hybrid offspring and their parents were inoculated into 3-months-old black pine(Pinus tunbergii) seedlings. Weaker pathogenicity of hybrid offspring was observed compared with that of their parents, and significantly fewer offspring nematodes than parents were reisolated from pines. Therefore, the offspring of B. xylophilus and B. mucronatus may exist in the forest and could influence disease epidemics.
基金financially supported by the National Key Research and Development Program(2017YFD0600105)the National Natural Science Foundation of China(Grant No.31870641)+2 种基金the Research Foundation of Education Department of Fujian Province(No.JAT170882)Project of Financial Department of Fujian Province(Nos.K81139238 and K8911010)the Special Fund for Forestry Research in the Public Interest of China(No.201304401)
文摘Pine wilt disease(PWD)is a devastating disease affecting the growth of Pinus massoniana,often leading to withering and death.To reveal the changes involved during disease progression,we investigated the mRNA expression profile of P.massoniana infested by Bursaphelenchus xylophilus.The infestation resulted in the downregulation of genes involved in interactions with pathogenic pathways such as disease resistance gene,CC-NBS-LRR resistancelike protein,and the gene encoding a putative nematode resistance protein.Increased infestation pressure(number of nematodes inoculated)caused a continuous decline in the gene expression of stem samples.An infestation of P.massoniana also resulted in a pathway enrichment of genes involved in phenylpropanoid metabolism and flavonoid biosynthesis,which in turn reduced the levels of total phenols and total flavonoids.A downregulation of auxin responsive family protein was observed in infested samples,which resulted in a suppression of plant growth.Thus,upon B.xylophilus infestation,a downregulation of genes associated with the recognition of pathogens,PWD resistance,and growth regulation was observed in P.massoniana,together with a decrease in the levels of phytoalexinlike secondary substances,all of which resulted in withering and ultimately death of P.massoniana.
文摘The invasion of Bursaphelenchus xylophilus （pine wood nematode, PWN） carried by Monochamus alternatus predominately attacks Masson pine （Pinus massoniana） forests and causes great economic losses in China. In this study, we assessed whether the effect of the invasion of PWN is different between island and inland forests. Arthropods were sampled in Fuyang （inland） and Zhoushan （island） counties in Zhejiang Province with sweep netting and light traps at four plots. During two field periods （May to June 2004 and September to October 2005） a total of 21,916 insects, representing 384 species belonging to 99 families and 15 orders, were collected in the sample plots from the island, whereas, from the inland forest a total of 29,262 insects, representing 308 species belonging to 96 families and 13 orders, were found. A hierarchical cluster analysis （HCA） and one-way ANOVA, based on the composition of different arthropod guilds, were performed. The results showed that there was no significant difference in the composition of arthropod communities at the family level between inland and island. But these two habitats had a significant effect on the composition of species, individuals, sub-communities and energy class levels. Statistically, the composition of the two orders, Lepidoptera and Diptera, in the two habitats were significantly different.
文摘Our research focused on Pinus massoniana information extracted from remote sensing images based on the knowledge detection and decision tree algorithm and established a spatial pattern model, combining quantitative theoretical ecology with remote sensing （RS） and geometric information system （GIS） techniques. Applying information extraction methods and a spatial pattern model, we studied P. massoniana spatial patterns changes before and after the invasion by pine wood nematode （Bursaphelenchus xylophilus） in Fuyang and Zhoushan counties, Zhejiang Province, east China. The P. massoniana spatial patterns are clustering, whether the invasion happened or not. But the degree of clustering is different. Our results show good agreement with field data. Applying the results, we analyzed the relationship between spatial patterns and the invasion level. Then we drew the elementary conclusion that there are two kinds of patterns for pine wood nematode to spread： continuous and discontinuous diffusion. This approach can help monitor and evaluate the changes in ecological systems.
文摘Pine wood nematode （PWN）, Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion, we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme “Prevention is priority, but integrated with curative techniques and ecological resilience” on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosys-tems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way.
