Rice stripe disease,caused by rice stripe virus (RSV) which is transmitted by small brown planthopper (SBPH,Laodelphax striatellus Fallen),resulted in serious losses to rice production during the last 2 decades.Resear...Rice stripe disease,caused by rice stripe virus (RSV) which is transmitted by small brown planthopper (SBPH,Laodelphax striatellus Fallen),resulted in serious losses to rice production during the last 2 decades.Research on the molecular differences between resistant and susceptible rice varieties and the interaction between rice and RSV remains inadequate.In this study,RNA-Seq was used to analyze the transcriptomic differences between the resistant and susceptible rice varieties at different times post RSV infection.Through Gene Ontology (GO) annotation,the differentially expressed genes (DEGs) related to transcription factors,peroxidases,and kinases of 2 varieties at 3 time points were identified.Comparing these 2 varieties,the DEGs associated with these 3 GOs were numerically less in the resistant variety than in the susceptible variety,but the expression showed a significant up-or down-regulation trend under the conditions of|log_2(Fold change)|>0&P_(adj)<0.05 by significance analysis.Then through Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation,DEGs involved in some pathways that have a contribution to disease resistance including plant hormone signal transduction and plant–pathogen interaction were found.The results showed that resistance responses regulated by abscisic acid (ABA) and brassinosteroids (BR) were the same for 2 varieties,but that mediated by salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) were different.The DEGs in resistant and susceptible varieties at the 3 time points were identified in both PAMP-triggered immunity (PTI) and Effector proteintriggered immunity (ETI),with that most of the unigenes of the susceptible variety were involved in PTI,whereas most of the unigenes of the resistant variety were involved in ETI.These results revealed the different responses of resistant and susceptible varieties in the transcription level to RSV infection.展开更多
Herbivore-induced plant volatiles(HIPVs)play a key role in the interactions between plants and herbivorous insects,as HIPVs can promote or deter herbivorous insects’behavior.While aphids are common and serious phloem...Herbivore-induced plant volatiles(HIPVs)play a key role in the interactions between plants and herbivorous insects,as HIPVs can promote or deter herbivorous insects’behavior.While aphids are common and serious phloem-feeding pests in farmland ecosystems,little is known about how aphids use their sensitive olfactory system to detect HIPVs.In this study,the antennal transcriptomes of the aphid species Megoura crassicauda were sequenced,and expression level analyses of M.crassicauda odorant receptors(ORs)were carried out.To investigate the chemoreception mechanisms that M.crassicauda uses to detect HIPVs,we performed in vitro functional studies of the ORs using 11 HIPVs reported to be released by aphid-infested plants.In total,54 candidate chemosensory genes were identified,among which 20 genes were ORs.McraOR20 and McraOR43 were selected for further functional characterization because their homologs in aphids were quite conserved and their expression levels in antennae of M.crassicauda were relatively high.The results showed that McraOR20 specifically detected cis-jasmone,as did its ortholog ApisOR20 from the pea aphid Acyrthosiphon pisum,while McraOR43 did not respond to any of the HIPV chemicals that were tested.This study characterized the ability of the homologous OR20 receptors in the two aphid species to detect HIPV cis-jasmone,and provides a candidate olfactory target for mediating aphid behaviors.展开更多
Pea aphid,Acyrthosiphon pisum,is a serious pest of many different leguminous plants,and it mainly relies on its odorant receptors(Ors)to discriminate among host species.However,less is known about the role that Ors pl...Pea aphid,Acyrthosiphon pisum,is a serious pest of many different leguminous plants,and it mainly relies on its odorant receptors(Ors)to discriminate among host species.However,less is known about the role that Ors play in the host plant location.In this study,we identified a novel conserved odorant receptor clade by phylogenetic analysis,and conducted the functional analysis of ApisOr23 in A.pisum.The results showed that the homologous Ors from A.pisum,Aphis glycines and Aphis gossypii share 94.28% identity in amino acid sequences.Moreover,conserved motifs were analyzed using the annotated homologous Or23 from eight aphid species,providing further proof of the high conservation level of the Or23 clade.According to the tissue expression pattern analysis,ApisOr23 was mainly expressed in the antennae.Further functional study using a heterologous Xenopus expression system revealed that ApisOr23 was tuned to five plant volatiles,namely trans-2-hexen-1-al,cis-2-hexen-1-ol,1-heptanol,4’-ethylacetophenone,and hexyl acetate.Among them,trans-2-hexen-1-al,which is one of the main volatile organic compounds released from legume plants,activated the highest response of ApisOr23.Our findings suggest that the conserved Or23 clade in most aphid species might play an important role in host plant detection.展开更多
To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are th...To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.展开更多
Harmonia axyridis Pallas （Coleoptera： Coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of ...Harmonia axyridis Pallas （Coleoptera： Coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids （Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene）, from coccinellids （[-]-β-earyophyllene） and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds （[Z]-3- hexenol and [E]-2-hexenal） were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while （-）-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the （Z）-3-hexenol oriented both males and females to the odor source. The （E）-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.展开更多
Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being clean- ing and protection for the aphids and carbohyd...Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being clean- ing and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant at- traction. Here, ant＇s ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays （control vs. one of the aphid species）. However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses.展开更多
The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystem...The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystems, a field experiment was carried out in an experimental farm at Gembloux （Belgium） to study the effect of nettle margin strips on aphid and aphidophagous populations in close field crops, namely wheat （Triticum aestivum L.）, green pea （Pisum sativum L.） and rape （Brassicae napus L.）. The aphids and related beneficial populations were weekly assessed, from March to August 2005, by visual observations in two plots per field crop. A higher abundance of aphidophagous beneficials was collected in nettle strips when compared to the field crops. Particularly, the presence of predatory anthocorids, mirids and green lacewings was observed on nettle only. Nevertheless, the most abundant aphid predatory family, the Coccinellidae, was distributed in both environments, in nettle strips and in crop fields. The field margin supported a significantly higher density ofHarmonia axyridis than the field crops. In contrast, the field crops, green pea particularly, supported a higher density of Coccinella septempunctata. The distribution of the aphidophagous species, mainly the ladybirds, was discussed in relation to the host plant and related aphid species and their potential effect on integrated pest management.展开更多
In poultry,feed based on maggots,like larvae of black soldier fly(Hermetia illucens) is an attractive option to substitute current ingredients which are expensive and often in direct or indirect competition with human...In poultry,feed based on maggots,like larvae of black soldier fly(Hermetia illucens) is an attractive option to substitute current ingredients which are expensive and often in direct or indirect competition with human food.Little information is currently available on the utility of these larvae in poultry feed,so goals of this study were to determine whether larvae could be reared on horse manure under traditional farming conditions and to evaluate the growth performances of a local poultry fed these larvae and the fatty acids profiles of their meat.After freezing and thawing,larvae were introduced in the feed of Ardennaise chickens between 30 and 80 days of age.Birds in the control group received a commercial standard feed,while those in the treatment group received the same commercial feed in which 8% was substituted with whole fresh larvae corresponding to 2% on a dry matter basis.Means ± standard errors of larval length and weight were 20.67 ± 2.21 mm and 0.14 ± 0.02 g,respectively.Mean larval percentages of dry matter and of substances extractable in diethyl ether were 24.6% and 23.1%,respectively.Larval fatty acids profiles were predominantly composed of lauric acid(28.1%) and palmitic acid(22.0%).Least squares means of weekly weights of chicken,adjusted for the effects of sex,replication and initial weights,were significantly higher(P < 0.05) by 77.03 ± 53.37 g in larvae-fed than in control chickens.All other measurements were not statistically different between larvae-fed and control chicken,including fatty acid profiles,protein content and w6/w3 ratio.展开更多
基金supported by the National Key Research and Development Plan of China(2019YFE0108500)。
文摘Rice stripe disease,caused by rice stripe virus (RSV) which is transmitted by small brown planthopper (SBPH,Laodelphax striatellus Fallen),resulted in serious losses to rice production during the last 2 decades.Research on the molecular differences between resistant and susceptible rice varieties and the interaction between rice and RSV remains inadequate.In this study,RNA-Seq was used to analyze the transcriptomic differences between the resistant and susceptible rice varieties at different times post RSV infection.Through Gene Ontology (GO) annotation,the differentially expressed genes (DEGs) related to transcription factors,peroxidases,and kinases of 2 varieties at 3 time points were identified.Comparing these 2 varieties,the DEGs associated with these 3 GOs were numerically less in the resistant variety than in the susceptible variety,but the expression showed a significant up-or down-regulation trend under the conditions of|log_2(Fold change)|>0&P_(adj)<0.05 by significance analysis.Then through Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation,DEGs involved in some pathways that have a contribution to disease resistance including plant hormone signal transduction and plant–pathogen interaction were found.The results showed that resistance responses regulated by abscisic acid (ABA) and brassinosteroids (BR) were the same for 2 varieties,but that mediated by salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) were different.The DEGs in resistant and susceptible varieties at the 3 time points were identified in both PAMP-triggered immunity (PTI) and Effector proteintriggered immunity (ETI),with that most of the unigenes of the susceptible variety were involved in PTI,whereas most of the unigenes of the resistant variety were involved in ETI.These results revealed the different responses of resistant and susceptible varieties in the transcription level to RSV infection.
基金funded by the National Natural Science Foundation of China(31572072 and 31801994)the Shenzhen Science and Technology Program,China(KQTD20180411143628272)+1 种基金the Natural Science Foundation of Tianjin,China(18JCYBJC96100)the Tianjin Normal University Foundation,China(135305JF79)。
文摘Herbivore-induced plant volatiles(HIPVs)play a key role in the interactions between plants and herbivorous insects,as HIPVs can promote or deter herbivorous insects’behavior.While aphids are common and serious phloem-feeding pests in farmland ecosystems,little is known about how aphids use their sensitive olfactory system to detect HIPVs.In this study,the antennal transcriptomes of the aphid species Megoura crassicauda were sequenced,and expression level analyses of M.crassicauda odorant receptors(ORs)were carried out.To investigate the chemoreception mechanisms that M.crassicauda uses to detect HIPVs,we performed in vitro functional studies of the ORs using 11 HIPVs reported to be released by aphid-infested plants.In total,54 candidate chemosensory genes were identified,among which 20 genes were ORs.McraOR20 and McraOR43 were selected for further functional characterization because their homologs in aphids were quite conserved and their expression levels in antennae of M.crassicauda were relatively high.The results showed that McraOR20 specifically detected cis-jasmone,as did its ortholog ApisOR20 from the pea aphid Acyrthosiphon pisum,while McraOR43 did not respond to any of the HIPV chemicals that were tested.This study characterized the ability of the homologous OR20 receptors in the two aphid species to detect HIPV cis-jasmone,and provides a candidate olfactory target for mediating aphid behaviors.
基金funded by the National Natural Science Foundation of China(31572072 and 31725023)the Intergovernmental International Science,Technology and Innovation Cooperation Key Project,China(2019YFE0105800)the Shenzhen Science and Technology Program,China(KQTD20180411143628272)。
文摘Pea aphid,Acyrthosiphon pisum,is a serious pest of many different leguminous plants,and it mainly relies on its odorant receptors(Ors)to discriminate among host species.However,less is known about the role that Ors play in the host plant location.In this study,we identified a novel conserved odorant receptor clade by phylogenetic analysis,and conducted the functional analysis of ApisOr23 in A.pisum.The results showed that the homologous Ors from A.pisum,Aphis glycines and Aphis gossypii share 94.28% identity in amino acid sequences.Moreover,conserved motifs were analyzed using the annotated homologous Or23 from eight aphid species,providing further proof of the high conservation level of the Or23 clade.According to the tissue expression pattern analysis,ApisOr23 was mainly expressed in the antennae.Further functional study using a heterologous Xenopus expression system revealed that ApisOr23 was tuned to five plant volatiles,namely trans-2-hexen-1-al,cis-2-hexen-1-ol,1-heptanol,4’-ethylacetophenone,and hexyl acetate.Among them,trans-2-hexen-1-al,which is one of the main volatile organic compounds released from legume plants,activated the highest response of ApisOr23.Our findings suggest that the conserved Or23 clade in most aphid species might play an important role in host plant detection.
文摘To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.
文摘Harmonia axyridis Pallas （Coleoptera： Coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids （Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene）, from coccinellids （[-]-β-earyophyllene） and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds （[Z]-3- hexenol and [E]-2-hexenal） were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while （-）-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the （Z）-3-hexenol oriented both males and females to the odor source. The （E）-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.
文摘Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being clean- ing and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant at- traction. Here, ant＇s ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays （control vs. one of the aphid species）. However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses.
文摘The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystems, a field experiment was carried out in an experimental farm at Gembloux （Belgium） to study the effect of nettle margin strips on aphid and aphidophagous populations in close field crops, namely wheat （Triticum aestivum L.）, green pea （Pisum sativum L.） and rape （Brassicae napus L.）. The aphids and related beneficial populations were weekly assessed, from March to August 2005, by visual observations in two plots per field crop. A higher abundance of aphidophagous beneficials was collected in nettle strips when compared to the field crops. Particularly, the presence of predatory anthocorids, mirids and green lacewings was observed on nettle only. Nevertheless, the most abundant aphid predatory family, the Coccinellidae, was distributed in both environments, in nettle strips and in crop fields. The field margin supported a significantly higher density ofHarmonia axyridis than the field crops. In contrast, the field crops, green pea particularly, supported a higher density of Coccinella septempunctata. The distribution of the aphidophagous species, mainly the ladybirds, was discussed in relation to the host plant and related aphid species and their potential effect on integrated pest management.
文摘In poultry,feed based on maggots,like larvae of black soldier fly(Hermetia illucens) is an attractive option to substitute current ingredients which are expensive and often in direct or indirect competition with human food.Little information is currently available on the utility of these larvae in poultry feed,so goals of this study were to determine whether larvae could be reared on horse manure under traditional farming conditions and to evaluate the growth performances of a local poultry fed these larvae and the fatty acids profiles of their meat.After freezing and thawing,larvae were introduced in the feed of Ardennaise chickens between 30 and 80 days of age.Birds in the control group received a commercial standard feed,while those in the treatment group received the same commercial feed in which 8% was substituted with whole fresh larvae corresponding to 2% on a dry matter basis.Means ± standard errors of larval length and weight were 20.67 ± 2.21 mm and 0.14 ± 0.02 g,respectively.Mean larval percentages of dry matter and of substances extractable in diethyl ether were 24.6% and 23.1%,respectively.Larval fatty acids profiles were predominantly composed of lauric acid(28.1%) and palmitic acid(22.0%).Least squares means of weekly weights of chicken,adjusted for the effects of sex,replication and initial weights,were significantly higher(P < 0.05) by 77.03 ± 53.37 g in larvae-fed than in control chickens.All other measurements were not statistically different between larvae-fed and control chicken,including fatty acid profiles,protein content and w6/w3 ratio.
