Microbial associates are widespread in insects,some conferring a protection to their hosts against natural enemies like parasitoids.These protective symbionts may affect the infection success of the parasitoid by modi...Microbial associates are widespread in insects,some conferring a protection to their hosts against natural enemies like parasitoids.These protective symbionts may affect the infection success of the parasitoid by modifying behavioral defenses of their hosts,the development success of the parasitoid by conferring a resistance against it or by altering life-history traits of the emerging parasitoids.Here,we assessed the effects of different protective bacterial symbionts on the entire sequence of the host-parasitoid interaction(i.e.,from parasitoid attack to offspring emergence)between the pea aphid,Acyrthosiphon pisum,and its main parasitoid,Aphidius ervi and their impacts on the life-history traits of the emerging parasitoids.To test whether symbiont-mediated phenotypes were general or specific to particular aphid-symbiont associations,we considered several aphid lineages,each harboring a different strain of either Hamiltonella defensa or Regiella insecticola,two protective symbionts commonly found in aphids.We found that symbiont species and strains had a weak effect on the ability of aphids to defend themselves against the parasitic wasps during the attack and a strong effect on aphid resistance against parasitoid development.While parasitism resistance was mainly determined by symbionts,their effects on host defensive behaviors varied from one aphid-symbiont association to another.Also,the symbiotic status of the aphid individuals had no impact on the attack rate of the parasitic wasps,the parasitoid emergence rate from parasitized aphids nor the life-history traits of the emerging parasitoids.Overall,no correlations between symbiont effects on the different stages of the host-parasitoid interaction was observed,suggesting no trade-offs or positive associations between symbiont-mediated phenotypes.Our study highlights the need to consider various sequences of the host-parasitoid interaction to better assess the outcomes of protective symbioses and understand the ecological and evolutionary dynamics of insect-symbiont associations.展开更多
Multi-agent model is well-known to suit design of complex systems. This paradigm allows describing autonomous entities to interact together directly or through their environment. It is specially adapted to design 3D s...Multi-agent model is well-known to suit design of complex systems. This paradigm allows describing autonomous entities to interact together directly or through their environment. It is specially adapted to design 3D simulations taking into account spatial constraints on agents. In this work, we have designed a multi-agent model which adds a feature to the classical representation of agent: a body, encapsulating a physical model of the agent. We have applied this model to lipids and proteins belonging to the inner mitochondrial membrane, a biological membrane. Information provided by atomic structures is available through international databases and has been used to design a shape-based grain model for the agent body. We selected a model with three grains per molecule in which each grain is characterized by a type determining how they interact together and consequently the agent behaviors. Lipids and two kinds of protein structures have been described within this model allowing us to simulate their organization in membranes.展开更多
The objective of the present study was to evaluate the resistance of 10 accessions to P. infestans, by in-vitro inoculation of detached leaflets with a complex isolation of the fungus. Late blight, caused by the fungu...The objective of the present study was to evaluate the resistance of 10 accessions to P. infestans, by in-vitro inoculation of detached leaflets with a complex isolation of the fungus. Late blight, caused by the fungus Phytophthora infestans Mont. De Bary, is one of the most important diseases of the potato crop, and can destroy complete plantations in a short space of time. Chile is considered as a sub-centre of the origin of cultivated potatoes with many native potato varieties in the country. The different resistance components demonstrated that within the material of Chilean native Solanum, there was a wide range of variation to late blight. The resistant control (R-8906384) and the accessions UCT-34-Cor presented the lowest infection efficiency, small sizes of the lesions and low levels of sporulation classifying them as the most resistant. This suggests low efficiency of the infection and high resistance to penetration in these materials. The more susceptible accessions often presented a good level of resistance for one or few components. It would be of great interest to go into the genetic control of the different resistance components to know if the same level of resistance expressed for a component by different accessions is under the same genetic control or not.展开更多
Clubroot caused by the protist Plasmodiophora brassicae is a major disease affecting cultivated Brassica-ceae.Using a combination of quantitative trait locus(QTL)fine mapping,CRISPR-Cas9 validation,and extensive analy...Clubroot caused by the protist Plasmodiophora brassicae is a major disease affecting cultivated Brassica-ceae.Using a combination of quantitative trait locus(QTL)fine mapping,CRISPR-Cas9 validation,and extensive analyses of DNA sequence and methylation patterns,we revealed that the two adjacent neigh-boring NLR(nucleotide-binding and leucine-rich repeat)genes AT5G47260 and AT5G47280 cooperate in controlling broad-spectrum quantitative partial resistance to the root pathogen P.brassicae in Arabidopsis and that they are epigenetically regulated.The variation in DNA methylation is not associated with any nucleotide variation or any transposable element presence/absence variants and is stably inherited.Vari-ations in DNA methylation at the Pb-At5.2 QTL are widespread across Arabidopsis accessions and corre-late negatively with variations in expression of the two genes.Our study demonstrates that natural,stable,and transgenerationally inherited epigenetic variations can play an important role in shaping resistance to plant pathogens by modulating the expression of immune receptors.展开更多
Herbivorous insects frequently harbor bacterial symbionts that affect their ecol- ogy and evolution. Aphids host the obligatory endosymbiont Buchnera, which is requiredfor reproduction, together with facultative symbi...Herbivorous insects frequently harbor bacterial symbionts that affect their ecol- ogy and evolution. Aphids host the obligatory endosymbiont Buchnera, which is requiredfor reproduction, together with facultative symbionts whose frequencies vary across aphid populations. These maternally transmitted secondary symbionts have been particularlystudied in the pea aphid, Acyrthosiphon pisum, which harbors at least 8 distinct bacterial species （not counting Buchnera） having environmentally dependent effects on host fitness.In particular, these symbiont species are associated with pea aphid populations feeding on specific plants. Although they are maternally inherited, these bacteria are occasionallytransferred across insect lineages. One mechanism of such nonmaternal transfer is paternal transmission to the progeny during sexual reproduction. To date, transmission of secondarysymbionts during sexual reproduction of aphids has been investigated in only a handful of aphid lineages and 3 symbiont species. To better characterize this process, we investigatedinheritance patterns of 7 symbiont species during sexual reproduction of pea aphids through a crossing experiment involving 49 clones belonging to 9 host-specialized biotypes, and117 crosses. Symbiont species in the progeny were detected with diagnostic qualitative PCR at the fundatrix stage hatching from eggs and in later parthenogenetic generations.We found no confirmed case of paternal transmission of symbionts to the progeny, and we observed that maternal transmission of a particular symbiont species （Serratia symbiotica）was quite inefficient. We discuss these observations in respect to the ecology of the pea aphid.展开更多
Interactions between plants and phytophagous insects play an important part in shaping the biochemical composition of plants. Reciprocally plant metabolites can influ- ence major life history traits in these insects a...Interactions between plants and phytophagous insects play an important part in shaping the biochemical composition of plants. Reciprocally plant metabolites can influ- ence major life history traits in these insects and largely contribute to their fitness. Plant rhizospheric microorganisms are an important biotic factor modulating plant metabolites and adaptation to stress. While plant-insects or plant-microorganisms interactions and their consequences on the plant metabolite signature are well-documented, the impact of soil microbial communities on plant defenses against phytophagous insects remains poorly known. In this study, we used oilseed rape （Brassica napus） and the cabbage root fly （Delia radicum） as biological models to tackle this question. Even though D. radicum is a belowground herbivore as a larva, its adult life history traits depend on aboveground signals. We therefore tested whether soil microbial diversity influenced emergence rate and fitness but also fly oviposition behavior, and tried to link possible effects to modifications in leaf and root metabolites. Through a removal-recolonization experiment, 3 soil microbial modalities （＂high,＂ ＂medium,＂ ＂low＂） were established and assessed through amplicon sequencing of 16S and 18S ribosomal RNA genes. The ＂medium＂ modality in the rhizosphere significantly improved insect development traits. Plant-microorganism interactions were marginally associated to modulations of root metabolites profiles, which could partly explain these results. We highlighted the potential role of plant-microbial interaction in plant defenses against Delia radicum. Rhizospheric microbial communities must be taken into account when analyzing plant defenses against herbivores, being either below or aboveground.展开更多
Symbiotic associations between microbes and insects are widespread, and it is frequent that several symbionts share the same host individual. Hence, interactions can occur between these symbionts, influencing their re...Symbiotic associations between microbes and insects are widespread, and it is frequent that several symbionts share the same host individual. Hence, interactions can occur between these symbionts, influencing their respective abundance within the host with consequences on its phenotype. Here, we investigate the effects of multiple infections in the pea aphid, Acyrthosiphon pisurn, which is the host of an obligatory and several facultative symbionts. In particular, we study the influence of a coinfection with 2 protective symbionts： Harniltonella defensa, which confers protection against parasitoids, and Rickettsiella viridis, which provides protection against fungal pathogens and predators. The effects of Hamiltonella-Rickettsiella coinfection on the respective abundance of the symbionts, host fitness and efficacy of enemy protection were studied. Asymmetrical interactions between the 2 protective symbionts have been found： when they coinfect the same aphid individuals, the Rickettsiella infection affected Hamiltonella abundance within hosts but not the Hamiltonella-mediated protective phenotype while the Hamiltonella infection negatively influences the Rickettsiella-mediated protective phenotype but not its abundance. Harboring the 2 protective symbionts also reduced the survival and fecundity of host individuals. Overall, this work highlights the effects of multiple infections on symbiont abundances and host traits that are likely to impact the maintenance of the symbiotic associations in natural habitats.展开更多
The impact of osmotic stress on growth, physiolo- gy, and metabolism of winter oilseed rape （Brassica napus L.） was investigated by detailed analysis of biomass traits, hormone metabolites and osmolytes in two genet...The impact of osmotic stress on growth, physiolo- gy, and metabolism of winter oilseed rape （Brassica napus L.） was investigated by detailed analysis of biomass traits, hormone metabolites and osmolytes in two genetically unrelated drought-tolerant genotypes and two unrelated drought-sensitive genotypes. Seedlings were grown in vitro under controlled conditions and osmotic stress was simulated by applying a gradual treatment with polyethylene glycol （PEG 6ooo）, followed by hypo-osmotic treatment of variants used for metabolite determination. The results provide a basis for the identification of reliable selection criteria for drought resistance in oilseed rape. The in vitro cultivation system established during this study enabled effective discrimination of early osmotic stress responses between drought-resistant and -susceptible oilseed rape genotypes that also show large differences in relative seed yield under drought conditions in the field. Clear physiological and metabolic differences wereobserved between the drought-resistant and drought-sensitive genotypes, suggesting that osmotic adjustment is a key component of drought response in oilseed rape. Unexpected- ly, however, the drought-resistant genotypes did not show typical hormonal adjustment and osmolyte accumulation, suggesting that they possess alternative physiological mech- anisms enabling avoidance of stress symptoms.展开更多
Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects.However,few studies have focused on chemosensory proteins(CSPs)for aphid host-location mechanisms.The roles ...Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects.However,few studies have focused on chemosensory proteins(CSPs)for aphid host-location mechanisms.The roles of CSPs in searching for different Poaceae species(wheat,barley,triticale,maize and sorghum)were tested in Rhopalosiphum padi,an important cereal pest.The olfactometer assays showed that R.padi responds to plant odors.Seven R.padi CSP genes were identified.Influence of aphid morph,tissue and starvation state on expression patterns of CSPs was evaluated.Expression levels of CSPI,CSP4,CSP5 and CSP6 in winged aphids were significantly higher than those in wingless ones.Transcription levels of four genes(CSPI,CSP4,CSP5 and CSP6)were relatively higher in the head with antennae,and the four genes tended to be upregulated follow ing starvation.Silencing of three CSPs(CSP4,CSP5 and CSP6)altered aphid host-location behavior in response to the five different host plants tested.Three volatile compounds of host plants(octanal,[E]-2-hexenol and linalool)have signif-icant attraction to winged R.padi according to the four-arm olfactometer tests.Molecular docking predicted hydrogen bonding sites which played key roles in the binding of CSP4,CSP5 and CSP6 with volatile compounds.Knockdown of CSP4 or CSP5 significantly decreased the staying time of R.padi in the arms with octanal.However,knockdown of CSP6 could not affect the response of R.padi to octanal.These results bring evidence for the involvement of three CSPs in R.padi host-location behavior.展开更多
Since its discovery as a bacterial adaptive immune system and its development for genome editing in eukaryotes,the CRISPR technology has revolutionized plant research and precision crop breeding.The CRISPR toolbox hol...Since its discovery as a bacterial adaptive immune system and its development for genome editing in eukaryotes,the CRISPR technology has revolutionized plant research and precision crop breeding.The CRISPR toolbox holds great promise in the production of crops with genetic disease resistance to increase agriculture resilience and reduce chemical crop protection with a strong impact on the environment and public health.In this review,we provide an extensive overviewon recent breakthroughs in CRISPR technology,including the newly developed prime editing system that allows precision gene editing in plants.We present how each CRISPR tool can be selected for optimal use in accordance with its specific strengths and limitations,and illustrate how the CRISPR toolbox can foster the development of genetically pathogen-resistant crops for sustainable agriculture.展开更多
The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we in...The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we investigated whether and how the presence of certain FS could affect phenoloxidase(PO)activity,a key component of insect innate immunity,under normal and stressed conditions.For this,we used clones of A.pisum of difTerent genetic backgrounds(LLOl,YR2 and T3-8V1)lacking FS or harboring one or two(Regiella insecticola,Hamiltonella defensa,Serratia symbiotica Rickettsiella viridis).Gene expression and proteomics analyses of the aphid hemolymph indicated that the two A.pisum POs,PPOl and PP02,are expressed and translated into proteins.The level of PPO genes expression as well as the amount of PPO proteins and phenoloxidase activity in the hemolymph depended on both the aphid genotype and FS species.In particular,H.defensa and R.insecticola,but not S.symbiotica-h R.viridis,caused a sharp decrease in PO activity by interfering with both transcription and translation.The microinjection of different types of stressors(yeast,Escherichia coli,latex beads)in the YR2 lines hosting different symbionts affected the survival rate of aphids and,in most cases,also decreased the expression of PPO genes after 24 h.The amount and activity of PPO proteins varied according to the type of FS and stressor,without clear corresponding changes in gene expression.These data demonstrate that the presence of certain FS influences an important component of pea aphid immunity.展开更多
Many aphid species exhibit a variation in reproductive mode which is influenced by winter climate regimes,with cyclical parthenogenetic (CP)lines dominating in cold winter areas (because they produce cold-resistant eg...Many aphid species exhibit a variation in reproductive mode which is influenced by winter climate regimes,with cyclical parthenogenetic (CP)lines dominating in cold winter areas (because they produce cold-resistant eggs)and obligate parthenogenetic (OP) ones in mild winter regions (because of their parthenogenetic overwintering).Genetic studies on several aphid species have shown that the OP trait can be transmitted during sexual events involving the 2 types of lines.This genetic system could be considered as a local safeguarding mechanism for OP alleles in case severe frost would have killed all parthenogenetically overwintering individuals.However,this strategy would only be efficient in restoring local polymorphism in breeding systems if the newly hatched OP recombinants remain competitive over their CP counterparts.In this study we compared egg hatching sequences of CP and OP F1 clones from several crosses obtained for 2 cereal aphid species,Sitobion avenae (constant 5℃,8 h of light)and Rhopalosiphum padi (winter outdoor conditions).For S.avenae,we obtained F1 offspring from 6 crosses, involving 4 clones while in R.padi F1 were obtained from 11 crosses involving 14 clones. We showed that in both species proportions of OP clones were higher in the first half of the progeny relative to the second half.In addition,F1 OP clones hatched in the mean about a week earlier than their CP sibs,which gives them a demographic advantage at the start of the growth season.We then discussed the consequences of this fitness advantage for the maintenance and spread of the OP trait in aphid populations.展开更多
基金This study was supported by the project ANR Hmicmac 16-CE02-0014 to J.C.S.and Y.O.
文摘Microbial associates are widespread in insects,some conferring a protection to their hosts against natural enemies like parasitoids.These protective symbionts may affect the infection success of the parasitoid by modifying behavioral defenses of their hosts,the development success of the parasitoid by conferring a resistance against it or by altering life-history traits of the emerging parasitoids.Here,we assessed the effects of different protective bacterial symbionts on the entire sequence of the host-parasitoid interaction(i.e.,from parasitoid attack to offspring emergence)between the pea aphid,Acyrthosiphon pisum,and its main parasitoid,Aphidius ervi and their impacts on the life-history traits of the emerging parasitoids.To test whether symbiont-mediated phenotypes were general or specific to particular aphid-symbiont associations,we considered several aphid lineages,each harboring a different strain of either Hamiltonella defensa or Regiella insecticola,two protective symbionts commonly found in aphids.We found that symbiont species and strains had a weak effect on the ability of aphids to defend themselves against the parasitic wasps during the attack and a strong effect on aphid resistance against parasitoid development.While parasitism resistance was mainly determined by symbionts,their effects on host defensive behaviors varied from one aphid-symbiont association to another.Also,the symbiotic status of the aphid individuals had no impact on the attack rate of the parasitic wasps,the parasitoid emergence rate from parasitized aphids nor the life-history traits of the emerging parasitoids.Overall,no correlations between symbiont effects on the different stages of the host-parasitoid interaction was observed,suggesting no trade-offs or positive associations between symbiont-mediated phenotypes.Our study highlights the need to consider various sequences of the host-parasitoid interaction to better assess the outcomes of protective symbioses and understand the ecological and evolutionary dynamics of insect-symbiont associations.
文摘Multi-agent model is well-known to suit design of complex systems. This paradigm allows describing autonomous entities to interact together directly or through their environment. It is specially adapted to design 3D simulations taking into account spatial constraints on agents. In this work, we have designed a multi-agent model which adds a feature to the classical representation of agent: a body, encapsulating a physical model of the agent. We have applied this model to lipids and proteins belonging to the inner mitochondrial membrane, a biological membrane. Information provided by atomic structures is available through international databases and has been used to design a shape-based grain model for the agent body. We selected a model with three grains per molecule in which each grain is characterized by a type determining how they interact together and consequently the agent behaviors. Lipids and two kinds of protein structures have been described within this model allowing us to simulate their organization in membranes.
文摘The objective of the present study was to evaluate the resistance of 10 accessions to P. infestans, by in-vitro inoculation of detached leaflets with a complex isolation of the fungus. Late blight, caused by the fungus Phytophthora infestans Mont. De Bary, is one of the most important diseases of the potato crop, and can destroy complete plantations in a short space of time. Chile is considered as a sub-centre of the origin of cultivated potatoes with many native potato varieties in the country. The different resistance components demonstrated that within the material of Chilean native Solanum, there was a wide range of variation to late blight. The resistant control (R-8906384) and the accessions UCT-34-Cor presented the lowest infection efficiency, small sizes of the lesions and low levels of sporulation classifying them as the most resistant. This suggests low efficiency of the infection and high resistance to penetration in these materials. The more susceptible accessions often presented a good level of resistance for one or few components. It would be of great interest to go into the genetic control of the different resistance components to know if the same level of resistance expressed for a component by different accessions is under the same genetic control or not.
文摘Clubroot caused by the protist Plasmodiophora brassicae is a major disease affecting cultivated Brassica-ceae.Using a combination of quantitative trait locus(QTL)fine mapping,CRISPR-Cas9 validation,and extensive analyses of DNA sequence and methylation patterns,we revealed that the two adjacent neigh-boring NLR(nucleotide-binding and leucine-rich repeat)genes AT5G47260 and AT5G47280 cooperate in controlling broad-spectrum quantitative partial resistance to the root pathogen P.brassicae in Arabidopsis and that they are epigenetically regulated.The variation in DNA methylation is not associated with any nucleotide variation or any transposable element presence/absence variants and is stably inherited.Vari-ations in DNA methylation at the Pb-At5.2 QTL are widespread across Arabidopsis accessions and corre-late negatively with variations in expression of the two genes.Our study demonstrates that natural,stable,and transgenerationally inherited epigenetic variations can play an important role in shaping resistance to plant pathogens by modulating the expression of immune receptors.
文摘Herbivorous insects frequently harbor bacterial symbionts that affect their ecol- ogy and evolution. Aphids host the obligatory endosymbiont Buchnera, which is requiredfor reproduction, together with facultative symbionts whose frequencies vary across aphid populations. These maternally transmitted secondary symbionts have been particularlystudied in the pea aphid, Acyrthosiphon pisum, which harbors at least 8 distinct bacterial species （not counting Buchnera） having environmentally dependent effects on host fitness.In particular, these symbiont species are associated with pea aphid populations feeding on specific plants. Although they are maternally inherited, these bacteria are occasionallytransferred across insect lineages. One mechanism of such nonmaternal transfer is paternal transmission to the progeny during sexual reproduction. To date, transmission of secondarysymbionts during sexual reproduction of aphids has been investigated in only a handful of aphid lineages and 3 symbiont species. To better characterize this process, we investigatedinheritance patterns of 7 symbiont species during sexual reproduction of pea aphids through a crossing experiment involving 49 clones belonging to 9 host-specialized biotypes, and117 crosses. Symbiont species in the progeny were detected with diagnostic qualitative PCR at the fundatrix stage hatching from eggs and in later parthenogenetic generations.We found no confirmed case of paternal transmission of symbionts to the progeny, and we observed that maternal transmission of a particular symbiont species （Serratia symbiotica）was quite inefficient. We discuss these observations in respect to the ecology of the pea aphid.
文摘Interactions between plants and phytophagous insects play an important part in shaping the biochemical composition of plants. Reciprocally plant metabolites can influ- ence major life history traits in these insects and largely contribute to their fitness. Plant rhizospheric microorganisms are an important biotic factor modulating plant metabolites and adaptation to stress. While plant-insects or plant-microorganisms interactions and their consequences on the plant metabolite signature are well-documented, the impact of soil microbial communities on plant defenses against phytophagous insects remains poorly known. In this study, we used oilseed rape （Brassica napus） and the cabbage root fly （Delia radicum） as biological models to tackle this question. Even though D. radicum is a belowground herbivore as a larva, its adult life history traits depend on aboveground signals. We therefore tested whether soil microbial diversity influenced emergence rate and fitness but also fly oviposition behavior, and tried to link possible effects to modifications in leaf and root metabolites. Through a removal-recolonization experiment, 3 soil microbial modalities （＂high,＂ ＂medium,＂ ＂low＂） were established and assessed through amplicon sequencing of 16S and 18S ribosomal RNA genes. The ＂medium＂ modality in the rhizosphere significantly improved insect development traits. Plant-microorganism interactions were marginally associated to modulations of root metabolites profiles, which could partly explain these results. We highlighted the potential role of plant-microbial interaction in plant defenses against Delia radicum. Rhizospheric microbial communities must be taken into account when analyzing plant defenses against herbivores, being either below or aboveground.
文摘Symbiotic associations between microbes and insects are widespread, and it is frequent that several symbionts share the same host individual. Hence, interactions can occur between these symbionts, influencing their respective abundance within the host with consequences on its phenotype. Here, we investigate the effects of multiple infections in the pea aphid, Acyrthosiphon pisurn, which is the host of an obligatory and several facultative symbionts. In particular, we study the influence of a coinfection with 2 protective symbionts： Harniltonella defensa, which confers protection against parasitoids, and Rickettsiella viridis, which provides protection against fungal pathogens and predators. The effects of Hamiltonella-Rickettsiella coinfection on the respective abundance of the symbionts, host fitness and efficacy of enemy protection were studied. Asymmetrical interactions between the 2 protective symbionts have been found： when they coinfect the same aphid individuals, the Rickettsiella infection affected Hamiltonella abundance within hosts but not the Hamiltonella-mediated protective phenotype while the Hamiltonella infection negatively influences the Rickettsiella-mediated protective phenotype but not its abundance. Harboring the 2 protective symbionts also reduced the survival and fecundity of host individuals. Overall, this work highlights the effects of multiple infections on symbiont abundances and host traits that are likely to impact the maintenance of the symbiotic associations in natural habitats.
基金financial support from the French National Research Agency ANRthe National Research Council of Canada’s Genomics and Health Initiative program+2 种基金the German Federal Ministry of Education and Research (BMBF), within the European Knowledge-Based Bio-Economy (KBBE) consortium CONVIGOURthe Innovation Program "Breeding of climate-adapted crops" funded by the German Ministry of Consumer Protection, Nutrition and Agriculture, via the Federal Agency of Agriculture and Nutrition (BLE, Bonn)the German Society for the Promotion of Private Plant Breeding (GFP e.V.).
文摘The impact of osmotic stress on growth, physiolo- gy, and metabolism of winter oilseed rape （Brassica napus L.） was investigated by detailed analysis of biomass traits, hormone metabolites and osmolytes in two genetically unrelated drought-tolerant genotypes and two unrelated drought-sensitive genotypes. Seedlings were grown in vitro under controlled conditions and osmotic stress was simulated by applying a gradual treatment with polyethylene glycol （PEG 6ooo）, followed by hypo-osmotic treatment of variants used for metabolite determination. The results provide a basis for the identification of reliable selection criteria for drought resistance in oilseed rape. The in vitro cultivation system established during this study enabled effective discrimination of early osmotic stress responses between drought-resistant and -susceptible oilseed rape genotypes that also show large differences in relative seed yield under drought conditions in the field. Clear physiological and metabolic differences wereobserved between the drought-resistant and drought-sensitive genotypes, suggesting that osmotic adjustment is a key component of drought response in oilseed rape. Unexpected- ly, however, the drought-resistant genotypes did not show typical hormonal adjustment and osmolyte accumulation, suggesting that they possess alternative physiological mech- anisms enabling avoidance of stress symptoms.
基金the National Natural Science Foundation of China(grant nos.31972263,31901878 and 31772160)China Postdoctoral Science Foundation(grant no.2019M653773)。
文摘Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects.However,few studies have focused on chemosensory proteins(CSPs)for aphid host-location mechanisms.The roles of CSPs in searching for different Poaceae species(wheat,barley,triticale,maize and sorghum)were tested in Rhopalosiphum padi,an important cereal pest.The olfactometer assays showed that R.padi responds to plant odors.Seven R.padi CSP genes were identified.Influence of aphid morph,tissue and starvation state on expression patterns of CSPs was evaluated.Expression levels of CSPI,CSP4,CSP5 and CSP6 in winged aphids were significantly higher than those in wingless ones.Transcription levels of four genes(CSPI,CSP4,CSP5 and CSP6)were relatively higher in the head with antennae,and the four genes tended to be upregulated follow ing starvation.Silencing of three CSPs(CSP4,CSP5 and CSP6)altered aphid host-location behavior in response to the five different host plants tested.Three volatile compounds of host plants(octanal,[E]-2-hexenol and linalool)have signif-icant attraction to winged R.padi according to the four-arm olfactometer tests.Molecular docking predicted hydrogen bonding sites which played key roles in the binding of CSP4,CSP5 and CSP6 with volatile compounds.Knockdown of CSP4 or CSP5 significantly decreased the staying time of R.padi in the arms with octanal.However,knockdown of CSP6 could not affect the response of R.padi to octanal.These results bring evidence for the involvement of three CSPs in R.padi host-location behavior.
基金supported by the Investissement d’Avenir program of the French National Agency of Research for the project GENIUS(ANR-11-BTBR-0001_GENIUS)the Institut Carnot Plant2Pro program for the project POTATOCRISPsupported by the ANR project Immunereceptor(ANR-15-CE20-0007).
文摘Since its discovery as a bacterial adaptive immune system and its development for genome editing in eukaryotes,the CRISPR technology has revolutionized plant research and precision crop breeding.The CRISPR toolbox holds great promise in the production of crops with genetic disease resistance to increase agriculture resilience and reduce chemical crop protection with a strong impact on the environment and public health.In this review,we provide an extensive overviewon recent breakthroughs in CRISPR technology,including the newly developed prime editing system that allows precision gene editing in plants.We present how each CRISPR tool can be selected for optimal use in accordance with its specific strengths and limitations,and illustrate how the CRISPR toolbox can foster the development of genetically pathogen-resistant crops for sustainable agriculture.
基金funded by the China Scholarship Council(grant number:201506300039)supported by the French Government through the "Investments for the Future" programs LABEX SIGNALIFE ANR-ll-LABX-0028-01 and IDEX UCAJedi ANR-15-IDEX-01.
文摘The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we investigated whether and how the presence of certain FS could affect phenoloxidase(PO)activity,a key component of insect innate immunity,under normal and stressed conditions.For this,we used clones of A.pisum of difTerent genetic backgrounds(LLOl,YR2 and T3-8V1)lacking FS or harboring one or two(Regiella insecticola,Hamiltonella defensa,Serratia symbiotica Rickettsiella viridis).Gene expression and proteomics analyses of the aphid hemolymph indicated that the two A.pisum POs,PPOl and PP02,are expressed and translated into proteins.The level of PPO genes expression as well as the amount of PPO proteins and phenoloxidase activity in the hemolymph depended on both the aphid genotype and FS species.In particular,H.defensa and R.insecticola,but not S.symbiotica-h R.viridis,caused a sharp decrease in PO activity by interfering with both transcription and translation.The microinjection of different types of stressors(yeast,Escherichia coli,latex beads)in the YR2 lines hosting different symbionts affected the survival rate of aphids and,in most cases,also decreased the expression of PPO genes after 24 h.The amount and activity of PPO proteins varied according to the type of FS and stressor,without clear corresponding changes in gene expression.These data demonstrate that the presence of certain FS influences an important component of pea aphid immunity.
文摘Many aphid species exhibit a variation in reproductive mode which is influenced by winter climate regimes,with cyclical parthenogenetic (CP)lines dominating in cold winter areas (because they produce cold-resistant eggs)and obligate parthenogenetic (OP) ones in mild winter regions (because of their parthenogenetic overwintering).Genetic studies on several aphid species have shown that the OP trait can be transmitted during sexual events involving the 2 types of lines.This genetic system could be considered as a local safeguarding mechanism for OP alleles in case severe frost would have killed all parthenogenetically overwintering individuals.However,this strategy would only be efficient in restoring local polymorphism in breeding systems if the newly hatched OP recombinants remain competitive over their CP counterparts.In this study we compared egg hatching sequences of CP and OP F1 clones from several crosses obtained for 2 cereal aphid species,Sitobion avenae (constant 5℃,8 h of light)and Rhopalosiphum padi (winter outdoor conditions).For S.avenae,we obtained F1 offspring from 6 crosses, involving 4 clones while in R.padi F1 were obtained from 11 crosses involving 14 clones. We showed that in both species proportions of OP clones were higher in the first half of the progeny relative to the second half.In addition,F1 OP clones hatched in the mean about a week earlier than their CP sibs,which gives them a demographic advantage at the start of the growth season.We then discussed the consequences of this fitness advantage for the maintenance and spread of the OP trait in aphid populations.
