Crops produced using the practice of continuous cropping can become seriously damaged by plant-parasitic nematodes,an important indicator of continuous cropping obstacles.As a typical and important perennial economic ...Crops produced using the practice of continuous cropping can become seriously damaged by plant-parasitic nematodes,an important indicator of continuous cropping obstacles.As a typical and important perennial economic crop,dragon fruit is prone to serious plant-parasitic nematode infestation;however,whether it encounters continuous cropping obstacles remains unclear.Here,we studied plant-parasitic nematodes(Meloidogyne spp.and Tylenchorhynchus sp.)in the soil and roots,soil nematode communities,metabolic footprint,soil integrated fertility,and the yield of intensively planted dragon fruit under non-continuous cropping(Y1)and 3 years(Y3)and 5 years(Y5)of continuous cropping,to determine potential continuous-cropping obstacles and factors that affect the yield of this fruit.The largest numbers of plant-parasitic nematodes in the soil and roots were observed in Y5;the associated yield was reduced,and the dragon fruit was severely stressed.Further analysis of the composition,diversity,and ecological function indices of soil nematodes showed that the soil ecological environment deteriorated after 3 years of continuous cropping,with Y5 having the worst results.Similarly,the soil at Y5 had a significant inhibitory effect on the growth and reproduction of Caenorhabditis elegans.Mantel test analysis and a random forest model showed that soil available phosphorus,soil exchange calcium,and soil nematode abundance and diversity were related significantly to yield.Partial least squares path modeling revealed that soil fertility and soil nematode diversity directly impacts the yield of continuously cropped dragon fruit.In summary,continuous cropping obstacles occurred in Y5 of intensive dragon fruit cultivation,with soil nematode diversity and soil fertility determining the crop's yield.展开更多
Entomopathogenic nematodes(EPNs)represent a promising biological control strategy for managing insect pest populations,offering an environmentally sustainable alternative to conventional chemical pesticides.This revie...Entomopathogenic nematodes(EPNs)represent a promising biological control strategy for managing insect pest populations,offering an environmentally sustainable alternative to conventional chemical pesticides.This review examines the application of EPNs in forestry,highlighting their biological and ecological characteristics,mechanisms of action,and efficacy against key forest pests.By exploring various methods of EPN application,including soil injection,foliar spray,and trunk injection,practical challenges and potential solutions for effective implementation are assessed.Case studies demonstrate successful use of EPNs in controlling pests such as bark beetles,wood borers,and root weevils,underscoring their potential for integration into integrated pest management(IPM)programs.Despite current limitations,including environmental sensitivity and application constraints,ongoing research and technological advancements continue to enhance the efficacy and reliability of EPNs.This review underscores the importance of EPNs in sustainable forestry practices and calls for further research to optimize their use and to address existing challenges,ultimately contributing to healthier forest ecosystems and reduced reliance on chemical pesticides.展开更多
Root-knot nematodes(RKNs)are the most widespread soil-borne obligate endoparasites.They can infect the roots of many crops and cause significant yield losses.The only commercially available RKN-resistant gene in tomat...Root-knot nematodes(RKNs)are the most widespread soil-borne obligate endoparasites.They can infect the roots of many crops and cause significant yield losses.The only commercially available RKN-resistant gene in tomatoes,Mi-1.2,fails at soil temperatures above 28℃.We cloned the heat-stable RKN-resistant gene,Mi-9,from a gene cluster composed of seven nucleotide-binding sites and leucine-rich repeat(NBS-LRR)type resistant genes in Solanum arcunum accession LA2157.Screening nematode infections in individual and combinatorial knockouts of five NBS-LRR genes showed that Mi-9 Candidate 4(MiC-4)alone is sufficient to confer heat-stable RKN resistance.Our study identifies a new source of heat-stable resistance to RKN in tomatoes for challenging environmental conditions.We also showcase a roadmap for rapid characterization of resistance genes by combining comparative genomics and genome editing,with the potential to be utilized in other crops.展开更多
Exotic plant invasions and increased atmospheric carbon dioxide(CO_(2))concentration have been determined to independently affect soil nematodes,a key component of soil biota.However,little is known about the long-ter...Exotic plant invasions and increased atmospheric carbon dioxide(CO_(2))concentration have been determined to independently affect soil nematodes,a key component of soil biota.However,little is known about the long-term effects of these two global change factors and their interactive effects.Over three consecutive years,we cultivated invasive alien plant Xanthium strumarium and its two phylogenetically related natives under both ambient(aCO_(2))and elevated(eCO_(2))atmospheric CO_(2)concentrations,and determined the effects of the invader and natives on soil nematodes under different CO_(2)concentrations and the relevant mechanism.The abundance of total soil nematodes and that of the dominant trophic group(herbivores)were significantly affected by plant species and CO_(2)concentration,and these effects were dependent on the experimental duration,however,the Shannon-diversity of nematodes was not affected by these factors.Under aCO_(2),both invasive and native species significantly increased the total nematode abundance and that of the dominant trophic group with increasing experimental duration,and the amplitude of the increase was greater under the invader relative to the natives.The eCO_(2)increased total nematode abundance(second year)and that of the dominant trophic group(third year)under the invader,but not under the natives(or even decreased)with increasing experimental duration.Root litter had greater effects on soil nematode abundance than leaf litter and root exudates did.This study indicates that eCO_(2)would aggravate effects of invasive plants on soil nematodes by increasing abundance,and these effects would vary with the duration.展开更多
The strawberry crimp nematode(Aphelenchoides fragariae) is a serious pathogen of ornamental crops and a significant quarantine concern in approximately 50 countries and regions,including China.A nematode population be...The strawberry crimp nematode(Aphelenchoides fragariae) is a serious pathogen of ornamental crops and a significant quarantine concern in approximately 50 countries and regions,including China.A nematode population belonging to the genus Aphelenchoides was isolated from symptomatic leaves of fuchsia plants(Fuchsia×hybrida Hort.ex Sieb.& Voss.) in Chengdu,Sichuan Province,China.Morphological and morphometric characteristics were determined using light microscopy and scanning electron microscopy.Detailed examination revealed diagnostic features consistent with A.fragariae.Three ribosomal DNA(rDNA) regions,i.e.,partial small subunit(SSU) rRNA,D2-D3 expansion segments of the large subunit(LSU) rRNA,and the internal transcribed spacer(ITS),were amplified and sequenced.Bayesian phylogenetic analyses based on these sequences placed the isolate in a well-supported monophyletic clade with reference A.fragariae specimens,clearly separated from other Aphelenchoides species.Furthermore,host-suitability assays demonstrated that this nematode population not only infects and reproduces on Fuchsia×hybrida,but also on Fragaria ananassa and Pteris vittata,two known hosts of A.fragariae.Collectively,morphological,molecular,and host-range evidence confirm the identification of this nematode as A.fragariae.To our knowledge,this represents the first molecular and morphological confirmation of A.fragariae in China,and the first report of Fuchsia×hybrida as a natural host for this species.展开更多
This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing hos...This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technology, as well as the existing problem and applying foreground were also discussed.展开更多
The vertical distribution of the dominant genera of plant nematodes at the depth of 0–150 cm of an aquic brown soil were studied for four land use patterns, i.e., paddy field, maize field, fallow field and woodland i...The vertical distribution of the dominant genera of plant nematodes at the depth of 0–150 cm of an aquic brown soil were studied for four land use patterns, i.e., paddy field, maize field, fallow field and woodland in the Shenyang Experimental Station of Ecology, Chi- nese Academy of Sciences in November of 2003. The results showed that the numbers of some dominant genera under different land uses decreased with the increase of soil depth. Helicotylenchus was most dominant genus under each land use type. Genera of Filenchus, Psilen- chus and Tylenchus in paddy field occurred at the depth of 0–20 cm; while Paratylenchus in fallow field and woodland, as well as Praty- lenchus in maize field presented in the deeper soil layers (0–80 cm). Significant correlations between the numbers of dominant genera of plant nematodes and soil chemical properties were found in this study. The number of Helicotylenchus under different land uses was posi- tively correlated with C/N ratio, total C, total N, total P, alkai-N, and Olsen-P. The numbers of Filenchus and Paratylenchus in paddy field, Pratylenchus in maize field and Paratylenchus in fallow field were negatively correlated with soil pH, and positively correlated with total C, total N and alkai-N. This study results showed that it is essential to sample at a certain depth according to the vertical distribution informa- tion of different genera of plant nematodes in adequately assessing the population size of plant nematodes.展开更多
This study was designed to understand the impact of methyl bromide (MB) (CH3Br) and its alternatives on both free-living and root-knot nematodes in the soil. A randomized complete block experiment with six treatments ...This study was designed to understand the impact of methyl bromide (MB) (CH3Br) and its alternatives on both free-living and root-knot nematodes in the soil. A randomized complete block experiment with six treatments and 4 replicates (each replicate in a separate greenhouse) was established in Qingzhou, Shandong Province, China. In addition to MB and untreated control (CK) treatments there were four alternative soil fumigation practices including MB+virtually impermeable films (VIF), metam sodium (MS), MS +VIF and soil solarization combined with selected biological control agents (SS+BCA). Two tomato (Lycopersicum esculentum Mill.) cultivars, cv. Maofen-802 from the Xian Institute of Vegetable Science, China, and cv. AF179 Brillante from the Israeli Hazera Quality Seeds, were selected as test crops. The results indicated that Rhabditidae was the most dominant population with percentage abundance as high as 85% of the total number of identified free-living nematodes, followed by that of Cephalobidae. Methyl bromide and its alternatives except for the non-chemical SS+BCA treatment controlled the target pest, root-knot nematodes. Also, the impact of the three chemical alternatives on free-living nematode number and functional group abundance was similar to the impact associated with a typical methyl bromide application. Chemical fumigation practices, especially that with MB, significantly reduced the number of nematodes in the soil and simultaneously significantly reduced the number of nematode genera thereby reducing nematode diversity. All the four soil chemical fumigation activities decreased soil microbial biomass and had an obvious initial impact on microorganism biomass. Furthermore, both plant-parasitic and fungivore nematodes were positively correlated with soil microbial biomass.展开更多
A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes...A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes. The result showed that the Bohai Bay and other coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of the benthos in these locations. And most offshore sampling sites in the middle of the Bohai Sea were clear and unpolluted.展开更多
One new species of free-living marine nematode of the genus Curvolaimus, Curvolaimus filiformis sp. nov. from the Huanghai Sea is described and illustrated. This new species is characterized by the buccal cavity teeth...One new species of free-living marine nematode of the genus Curvolaimus, Curvolaimus filiformis sp. nov. from the Huanghai Sea is described and illustrated. This new species is characterized by the buccal cavity teeth, large amphids and two ventral seta at the conical part of tail. Meanwhile, two new records of genus Halalaimus, Halalaimus longicaudatus and H. isaitshikovi are fast reported in China. Types are deposited in the College of Marine Life Sciences, Ocean University of China.展开更多
基金supported by the National Key Research and Development Program of China(2023YFD1700203and 2022YFD1901501)the Tianchi Talent Introduction Program of Xinjiang Autonomous Region,China(2023-“2+5”)the Tingzhou Talent Introduction Program of Changji Autonomous Region,China(2023)。
文摘Crops produced using the practice of continuous cropping can become seriously damaged by plant-parasitic nematodes,an important indicator of continuous cropping obstacles.As a typical and important perennial economic crop,dragon fruit is prone to serious plant-parasitic nematode infestation;however,whether it encounters continuous cropping obstacles remains unclear.Here,we studied plant-parasitic nematodes(Meloidogyne spp.and Tylenchorhynchus sp.)in the soil and roots,soil nematode communities,metabolic footprint,soil integrated fertility,and the yield of intensively planted dragon fruit under non-continuous cropping(Y1)and 3 years(Y3)and 5 years(Y5)of continuous cropping,to determine potential continuous-cropping obstacles and factors that affect the yield of this fruit.The largest numbers of plant-parasitic nematodes in the soil and roots were observed in Y5;the associated yield was reduced,and the dragon fruit was severely stressed.Further analysis of the composition,diversity,and ecological function indices of soil nematodes showed that the soil ecological environment deteriorated after 3 years of continuous cropping,with Y5 having the worst results.Similarly,the soil at Y5 had a significant inhibitory effect on the growth and reproduction of Caenorhabditis elegans.Mantel test analysis and a random forest model showed that soil available phosphorus,soil exchange calcium,and soil nematode abundance and diversity were related significantly to yield.Partial least squares path modeling revealed that soil fertility and soil nematode diversity directly impacts the yield of continuously cropped dragon fruit.In summary,continuous cropping obstacles occurred in Y5 of intensive dragon fruit cultivation,with soil nematode diversity and soil fertility determining the crop's yield.
文摘Entomopathogenic nematodes(EPNs)represent a promising biological control strategy for managing insect pest populations,offering an environmentally sustainable alternative to conventional chemical pesticides.This review examines the application of EPNs in forestry,highlighting their biological and ecological characteristics,mechanisms of action,and efficacy against key forest pests.By exploring various methods of EPN application,including soil injection,foliar spray,and trunk injection,practical challenges and potential solutions for effective implementation are assessed.Case studies demonstrate successful use of EPNs in controlling pests such as bark beetles,wood borers,and root weevils,underscoring their potential for integration into integrated pest management(IPM)programs.Despite current limitations,including environmental sensitivity and application constraints,ongoing research and technological advancements continue to enhance the efficacy and reliability of EPNs.This review underscores the importance of EPNs in sustainable forestry practices and calls for further research to optimize their use and to address existing challenges,ultimately contributing to healthier forest ecosystems and reduced reliance on chemical pesticides.
基金supported by the National Key R&D Program of China(2018YFA0900600 and 2021YFF1000103-5)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA24030503)。
文摘Root-knot nematodes(RKNs)are the most widespread soil-borne obligate endoparasites.They can infect the roots of many crops and cause significant yield losses.The only commercially available RKN-resistant gene in tomatoes,Mi-1.2,fails at soil temperatures above 28℃.We cloned the heat-stable RKN-resistant gene,Mi-9,from a gene cluster composed of seven nucleotide-binding sites and leucine-rich repeat(NBS-LRR)type resistant genes in Solanum arcunum accession LA2157.Screening nematode infections in individual and combinatorial knockouts of five NBS-LRR genes showed that Mi-9 Candidate 4(MiC-4)alone is sufficient to confer heat-stable RKN resistance.Our study identifies a new source of heat-stable resistance to RKN in tomatoes for challenging environmental conditions.We also showcase a roadmap for rapid characterization of resistance genes by combining comparative genomics and genome editing,with the potential to be utilized in other crops.
基金supported by the National Key R&D Program of China(2023YFC2604500)the National Natural Science Foundation of China(32171662,32471753 and 32171666)the Natural Science Foundation of Liaoning(2020-MS-199).
文摘Exotic plant invasions and increased atmospheric carbon dioxide(CO_(2))concentration have been determined to independently affect soil nematodes,a key component of soil biota.However,little is known about the long-term effects of these two global change factors and their interactive effects.Over three consecutive years,we cultivated invasive alien plant Xanthium strumarium and its two phylogenetically related natives under both ambient(aCO_(2))and elevated(eCO_(2))atmospheric CO_(2)concentrations,and determined the effects of the invader and natives on soil nematodes under different CO_(2)concentrations and the relevant mechanism.The abundance of total soil nematodes and that of the dominant trophic group(herbivores)were significantly affected by plant species and CO_(2)concentration,and these effects were dependent on the experimental duration,however,the Shannon-diversity of nematodes was not affected by these factors.Under aCO_(2),both invasive and native species significantly increased the total nematode abundance and that of the dominant trophic group with increasing experimental duration,and the amplitude of the increase was greater under the invader relative to the natives.The eCO_(2)increased total nematode abundance(second year)and that of the dominant trophic group(third year)under the invader,but not under the natives(or even decreased)with increasing experimental duration.Root litter had greater effects on soil nematode abundance than leaf litter and root exudates did.This study indicates that eCO_(2)would aggravate effects of invasive plants on soil nematodes by increasing abundance,and these effects would vary with the duration.
基金financially supported by the Shaanxi Innovation Team Project,China (2024RS-CXTD-73)the National Natural Science Foundation of China (31772136)。
文摘The strawberry crimp nematode(Aphelenchoides fragariae) is a serious pathogen of ornamental crops and a significant quarantine concern in approximately 50 countries and regions,including China.A nematode population belonging to the genus Aphelenchoides was isolated from symptomatic leaves of fuchsia plants(Fuchsia×hybrida Hort.ex Sieb.& Voss.) in Chengdu,Sichuan Province,China.Morphological and morphometric characteristics were determined using light microscopy and scanning electron microscopy.Detailed examination revealed diagnostic features consistent with A.fragariae.Three ribosomal DNA(rDNA) regions,i.e.,partial small subunit(SSU) rRNA,D2-D3 expansion segments of the large subunit(LSU) rRNA,and the internal transcribed spacer(ITS),were amplified and sequenced.Bayesian phylogenetic analyses based on these sequences placed the isolate in a well-supported monophyletic clade with reference A.fragariae specimens,clearly separated from other Aphelenchoides species.Furthermore,host-suitability assays demonstrated that this nematode population not only infects and reproduces on Fuchsia×hybrida,but also on Fragaria ananassa and Pteris vittata,two known hosts of A.fragariae.Collectively,morphological,molecular,and host-range evidence confirm the identification of this nematode as A.fragariae.To our knowledge,this represents the first molecular and morphological confirmation of A.fragariae in China,and the first report of Fuchsia×hybrida as a natural host for this species.
基金This paper was supported by Natural Science Founda-tion of Heilongjiang Province (No.C-9735).
文摘This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technology, as well as the existing problem and applying foreground were also discussed.
文摘The vertical distribution of the dominant genera of plant nematodes at the depth of 0–150 cm of an aquic brown soil were studied for four land use patterns, i.e., paddy field, maize field, fallow field and woodland in the Shenyang Experimental Station of Ecology, Chi- nese Academy of Sciences in November of 2003. The results showed that the numbers of some dominant genera under different land uses decreased with the increase of soil depth. Helicotylenchus was most dominant genus under each land use type. Genera of Filenchus, Psilen- chus and Tylenchus in paddy field occurred at the depth of 0–20 cm; while Paratylenchus in fallow field and woodland, as well as Praty- lenchus in maize field presented in the deeper soil layers (0–80 cm). Significant correlations between the numbers of dominant genera of plant nematodes and soil chemical properties were found in this study. The number of Helicotylenchus under different land uses was posi- tively correlated with C/N ratio, total C, total N, total P, alkai-N, and Olsen-P. The numbers of Filenchus and Paratylenchus in paddy field, Pratylenchus in maize field and Paratylenchus in fallow field were negatively correlated with soil pH, and positively correlated with total C, total N and alkai-N. This study results showed that it is essential to sample at a certain depth according to the vertical distribution informa- tion of different genera of plant nematodes in adequately assessing the population size of plant nematodes.
基金Project supported by the Sino-Italy Environmental Cooperation Fund.
文摘This study was designed to understand the impact of methyl bromide (MB) (CH3Br) and its alternatives on both free-living and root-knot nematodes in the soil. A randomized complete block experiment with six treatments and 4 replicates (each replicate in a separate greenhouse) was established in Qingzhou, Shandong Province, China. In addition to MB and untreated control (CK) treatments there were four alternative soil fumigation practices including MB+virtually impermeable films (VIF), metam sodium (MS), MS +VIF and soil solarization combined with selected biological control agents (SS+BCA). Two tomato (Lycopersicum esculentum Mill.) cultivars, cv. Maofen-802 from the Xian Institute of Vegetable Science, China, and cv. AF179 Brillante from the Israeli Hazera Quality Seeds, were selected as test crops. The results indicated that Rhabditidae was the most dominant population with percentage abundance as high as 85% of the total number of identified free-living nematodes, followed by that of Cephalobidae. Methyl bromide and its alternatives except for the non-chemical SS+BCA treatment controlled the target pest, root-knot nematodes. Also, the impact of the three chemical alternatives on free-living nematode number and functional group abundance was similar to the impact associated with a typical methyl bromide application. Chemical fumigation practices, especially that with MB, significantly reduced the number of nematodes in the soil and simultaneously significantly reduced the number of nematode genera thereby reducing nematode diversity. All the four soil chemical fumigation activities decreased soil microbial biomass and had an obvious initial impact on microorganism biomass. Furthermore, both plant-parasitic and fungivore nematodes were positively correlated with soil microbial biomass.
文摘A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes. The result showed that the Bohai Bay and other coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of the benthos in these locations. And most offshore sampling sites in the middle of the Bohai Sea were clear and unpolluted.
文摘One new species of free-living marine nematode of the genus Curvolaimus, Curvolaimus filiformis sp. nov. from the Huanghai Sea is described and illustrated. This new species is characterized by the buccal cavity teeth, large amphids and two ventral seta at the conical part of tail. Meanwhile, two new records of genus Halalaimus, Halalaimus longicaudatus and H. isaitshikovi are fast reported in China. Types are deposited in the College of Marine Life Sciences, Ocean University of China.
