The newly-hatched nymphs of the small brown planthopper (SBPH), Laodelphax striatellus, including field and sensitive populations, were subjected to the high-temperature (35°C) treatment. The number of yeast-like...The newly-hatched nymphs of the small brown planthopper (SBPH), Laodelphax striatellus, including field and sensitive populations, were subjected to the high-temperature (35°C) treatment. The number of yeast-like endosymbiotes in SBPH reduced by 23.47%–34.23%, 57.86%–61.51% and 88.96%–90.71% after the high-temperature treatment for 1 d, 2 d, and 3 d, respectively. However, the size of yeast-like endosymbiotes was not obviously affected. Resistance of SBPH to three insecticides (imidacloprid, chlorpyrifos and fipronil) decreased with the increase of treatment time.展开更多
Toll-like receptors(TLRs) are the critical superfamily homologues that initiate sensing of the invasion of pathogens by the Toll pathway. As one of several intracellular nucleic acid-sensing TLRs, TLR13 is activated b...Toll-like receptors(TLRs) are the critical superfamily homologues that initiate sensing of the invasion of pathogens by the Toll pathway. As one of several intracellular nucleic acid-sensing TLRs, TLR13 is activated by an unmethylated motif present in the large ribosomal subunit of bacterial RNA. However, little attention has been paid to the function of TLR13 gene homologue from Laodelphax striatellus(designated as LsToll-13) in the immune response to rice stripe virus(RSV). Herein, LsToll-13 was cloned and characterized using RACE-PCR. Phylogenetic analysis showed that LsToll-13 was clustered with the TLR13 from six insects. Real-time PCR analysis demonstrated that the expression level of LsToll-13 was significantly reduced in L. striatellus with RSV infection compared with that in the naive strain. When the expression of LsToll-13 was significantly up-regulated at 6 h after bacterial infection, the expression of ribonucleoprotein(RNP) indicated that the RSV titer in the host insect was significantly suppressed. Upon knockdown of LsToll-13, using RNA interference(RNAi) in L. striatellus, the expression level of RNP was significantly increased with enhanced RSV accumulation, suggesting that LsToll-13 potentially protects L. striatellus from RSV infection. Taken together, our results indicated that LsToll-13 might be involved in the immune response of L. striatellus to RSV infection, and provided a new insight into further elucidating the molecular mechanisms of complex pathogen-host interactions and integrative pest management.展开更多
The endosymbiont Wolbachia manipulates host reproduction by several strategies, one of the most important of which is cytoplasmic incompatibility (CI). CI can be rescued when Wolbachia-infected males mate with females...The endosymbiont Wolbachia manipulates host reproduction by several strategies, one of the most important of which is cytoplasmic incompatibility (CI). CI can be rescued when Wolbachia-infected males mate with females infected with the same Wolbachia strain. However, the potential rescue mechanism of CI in the small brown planthopper Laodelphax striatellus is unclear. In this study, comparative transcriptome analysis was applied to explore the effect of Wolbachia on L. striatellus eggs. A total of 1387 differentially expressed genes were identified. RNA interference of 7 Wolbachia-upregulated key planthopper genes reduced egg reproduction, suggesting that Wolbachia might improve fecundity in L. striatellus by affecting these 7 genes. Suppressing the expression of another upregulated gene, NDUFA8 (encoding NADH dehydrogenase [ubiquinone] 1 α subcomplex subunit 8-like) by RNA interference significantly increased the mortality of early embryos without affecting the number of deposited eggs. Wolbachia infection upregulated the mRNA level of NDUFA8, and dsNDUFA8 treatment of Wolbachia-infected females recreated CI-like symptoms, suggesting that NDUFA8 is associated with the rescue phenotype. Because all L. striatellus populations worldwide are infected with Wolbachia, NDUFA8 is a potential pest control target.展开更多
Fatty acid synthase (FAS) is a multifunctional enzyme that plays an important role in the formation of fatty acids. The fatty acids take part in many processes, such as cell signaling and energy metabolism, and in ins...Fatty acid synthase (FAS) is a multifunctional enzyme that plays an important role in the formation of fatty acids. The fatty acids take part in many processes, such as cell signaling and energy metabolism, and in insects they are important in both cuticular hydrocarbon (CHC) formation and reproduction. Here we characterized the sequence structure and function of an FAS from the small brown planthopper (SBPH), Laodelphax striatellus. The full-length open reading frame (ORF) sequence of LsFAS1 was 7122 bp, encoding a predicted protein of 2373 amino acid residues. There were 7 functional domains in the LsFAS1 protein sequence. Gene expression screening by real-time quantitative polymerase chain reaction (RT-qPCR) showed that LsFAS1 was expressed in all developmental stages. Relative expression was highest at the 4th-instar and female adult stages. Among different tissues, the expression level of LsFAS1 in the ovary was the highest. Phylogenetic analysis showed that LsFAS1 clustered in a clade with 2 FASs from Nilaparvata lugens. Furthermore, these 3 FASs are related to cockroach BgFAS and locust LmFAS. After RNA interference-mediated knock-down, most treated insects died at eclosion. In addition, the lifespan of dsFAS1-treated female adults was shorter than that of the dsGFP-injected control, and offspring production decreased. Also, the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes decreased. Virgin females dissected at days 2 and 4 post-eclosion showed many matured oocytes in planthoppers treated with dsGFP but not with dsFAS1. These data highlight the importance of LsFAS1 in SBPH, including a role in reproduction.展开更多
To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper (SBPH) Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral (RS...To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper (SBPH) Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral (RSV) disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics (AUCPD or planthopper-day accumulation) or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.展开更多
Bacteria symbionts in herbivores play an important role in host biology and ecology,and are affected by environmental factors such as temperature,diet,habitat,antibiotics and so on.However,the effects of antibiotics o...Bacteria symbionts in herbivores play an important role in host biology and ecology,and are affected by environmental factors such as temperature,diet,habitat,antibiotics and so on.However,the effects of antibiotics on the microbiome of the small brown planthopper Laodelphax striatellus(SBPH)remain unclear.Here,we studied the effects of tetracycline on the diversity and composition of bacterial colonies in different tissues of SBPH using high throughput sequencing of 16S ribosomal RNA amplicons.Our results show that Proteobacteria,Firmicutes,Bacteroidetes,Actinobacteria were most abundant in SBPH,and the genera Asaia and Wolbachia were most abundant in all body parts of SBPH.Antibiotic treatment had persistent effects on the composition of the SBPH microbiome.Tetracycline depleted the population of Firmicutes,Bacteroidetes,Tenericutes and Fusobacteria,and nearly 100%eliminated Wolbachia,Bacteroides and Abiotrophia in SBPH.Together,these results suggest that antibiotic exposure affects the bacteria symbionts of different body parts in SBPH and will facilitate future studies of the bacterial symbionts of arthropod hosts.展开更多
Ecdysteroid hormone 20-hydroxyecdysone plays fundamental roles in in- sect postembryonic development and reproduction. Several cytochrome P450 mono- oxygenases (CYPs), encoded by the Halloween genes, have been docum...Ecdysteroid hormone 20-hydroxyecdysone plays fundamental roles in in- sect postembryonic development and reproduction. Several cytochrome P450 mono- oxygenases (CYPs), encoded by the Halloween genes, have been documented to be involved in ecdysteroidogenesis in representative insects in Diptera, Lepidoptera and Orthoptera. Here the putative Halloween gene Phantom (Phm, cyp306al) from a hemipteran insect species, the small brown planthopper Laodelphax striatellus, was cloned. LsPHM shows five insect conserved P450 motifs, that is, Helix-C, Helix-I, Helix-K, PERF and heme- binding motifs. Temporal and spatial expression patterns of LsPhm were evaluated by quantitative polymerase chain reaction. Through the fourth-instar and the early fifth-instar stages, LsPhm showed two expression peaks in day 2 and days 4-5 fourth-instar nymphs, and three troughs in day 1 and 3 fourth instars and day 1 fifth instars. On day 5 of the fourth-instar nymphs, LsPhm clearly had a high transcript level in the thorax where the prothoracic glands were located. Dietary introduction of double-stranded RNA (dsRNA) of LsPhm at the nymph stage successfully knocked down the target gene, decreased expres- sion level ofecdysone receptor (LsEcR) gene and caused a higher nymphal mortality rate and delayed development. Ingestion of 20-hydroxyecdysone on LsPhm-dsRNA-exposed nymphs did not increase LsPhm expression level, but almost completely rescued the LsEcR mRNA level, and relieved the negative effects on survival and development. Thus, our data suggest that the putative LsPhm encodes a ftmctional 25-hydroxylase that catalyzes the biosynthesis of ecdysteroids in L. striatellus.展开更多
Rice stripe virus(RSV)is the causative agent of rice stripe disease and is completely dependent on insect vectors for its plant-to-plant transmission.Laodelphax striatellus is the major insect vector for RSV.In this s...Rice stripe virus(RSV)is the causative agent of rice stripe disease and is completely dependent on insect vectors for its plant-to-plant transmission.Laodelphax striatellus is the major insect vector for RSV.In this study,we explored the interactions be-tween RSV infection and L.striatellus autophagy,a potential intrinsic antiviral mechanism in insects.We found that L.striatellus autophagic activity did not affect RSV infection;however,the autophagy related-8(Atg8)gene significantly enhanced virus infection.Dur-ing RSV initial infection within the L.striatellus midgut,silencing of Atg8 expression significantly decreased the phosphorylation of c-Jun N-terminal kinase(p-JNK);however,when RSV infection is absent,silencing of Atg8 did not alter p-JNK levels.Thesc results indicated that Atg8 might activate the JNK machinery by allowing more virus infection into cells.We further revealed that Atg8-deficiency significantly decreased RSV accumu-lation on the surface of the insect midgut epithelial cells,suggesting a receptor trafficking function of the y-aminobutyric acid receptor-associated protein family.Using the RSV ovary entry as a model,in which vitellogenin receptor(V gR)mediates RSV cell entry,we clarified that Atg8-deficiency decreased the abundance of V gR localizing on the cytomem-brane and disturbed the attachment of RSV in the germarium zones.Collectively,these results revealed an autophagy-independent function of L.striatellus Atg8 that enhances RSV initial infection by increasing virus attachment on the infection sites.展开更多
Small brown planthopper, Laodelphax striatellus (Fall6n) numbers usually drop sharply in the summer and revive quickly in the autumn. However, it is unclear whether and how the high temperature plays a role in this ...Small brown planthopper, Laodelphax striatellus (Fall6n) numbers usually drop sharply in the summer and revive quickly in the autumn. However, it is unclear whether and how the high temperature plays a role in this process. The effects of durations of heat exposure (33~C) on life-history traits were examined here. Exposure of adults for 1 day during the oviposition stage led to a very low survival of nymphs. The average longevity ofL. striatellus exposed for 1-31 days from oviposition was significantly longer than that of the control (27℃). Short-term (1-5 days) heat exposure of the third instar nymphs did not significantly influence eclosion, but exposure of the fourth instar nymphs significantly increased eclosion. Lifespan from egg to adult was significantly lengthened when the third instar nymphs were exposed to heat for 2-15 days, or the fourth instar were exposed for 10 days. The preoviposition period was prolonged by heat exposure of the third or fourth instar nymphs. Short-term heat exposure of less than 3 days of the third or fourth instar nymphs did not restrict fecundity, but when the exposure duration exceeded 5 days the total eggs per female and hatchability decreased. Exposure to high temperature increased the brachypter rate of adults. In summary, low survival and slowing development under heat exposure resulted in population decline in the summer, and the relatively high fecundity and brachypter rate led to quick revival in autumn. Temperature in the summer determines the rise and fall in numbers ofL. striatellus.展开更多
The virus disease threatening wheat production in Hulunbcir District of Inner - Mongolia was identified as NCMV (Northern Cereal Mosaic Virus) or WRSV (Wheat Rosette Stunt Virus) by tests of host range, transmission, ...The virus disease threatening wheat production in Hulunbcir District of Inner - Mongolia was identified as NCMV (Northern Cereal Mosaic Virus) or WRSV (Wheat Rosette Stunt Virus) by tests of host range, transmission, virus particle and scrology. The main vector for spreading the virus is planthopper, Laodelphax striatellus (Fallen), which overwinters in the stubbles of wheat underground. The overwintered virulifcrous nymphs emerged in late April is responsible for the early infection of the disease. Agropyron repens, an important perennial weed in cultivated regions, is also an important wild host of the virus and its vector. Severe loss is induced when wheat is infected before 3 - leaf stage. The disease incidence could be predicted by a model with the population and virulifcrous rate of overwintered vectors as independent variables.展开更多
Rice planthoppers are notorious plant sap-feeding pests which cause serious damage.While several microbes in rice planthoppers have been broadly characterized,the abundance and diversity of bacteria and fungi in field...Rice planthoppers are notorious plant sap-feeding pests which cause serious damage.While several microbes in rice planthoppers have been broadly characterized,the abundance and diversity of bacteria and fungi in field planthoppers are largely unknown.This study investigated the bacterial and fungal community compositions of Chinese wild rice planthoppers Laodelphax striatellus and Sogatella furcifera using parallel 16S rRNA gene amplicon and internal transcribed space region sequencing.The bacteria varied sig-nificantly between the species and were partitioned significantly by sex,tissues and host environments in each species.The majority of bacteria were affiliated with the genera Wol-bachia,Cardinium,Rickettsia and Pantoea.The abundance of Wolbachia was negatively correlated with that of Cardinium in both planthopper species.Compared with bacteria,the abundance and diversity of fiungi did not differ between sexes but both were enriched in the gut.The bacterial community as a whole showed no significant correlation with the fungal community.The majority of fungi were related to Sarocldium,Alternaria,Malasseria,Aspergillus and Curvularia.A phylogenetic analysis revealed that these fungi were closely related to botanic symbionts or pathogens.Our results provide novel insights into the bacteria and fungi of rice planthoppers.展开更多
文摘The newly-hatched nymphs of the small brown planthopper (SBPH), Laodelphax striatellus, including field and sensitive populations, were subjected to the high-temperature (35°C) treatment. The number of yeast-like endosymbiotes in SBPH reduced by 23.47%–34.23%, 57.86%–61.51% and 88.96%–90.71% after the high-temperature treatment for 1 d, 2 d, and 3 d, respectively. However, the size of yeast-like endosymbiotes was not obviously affected. Resistance of SBPH to three insecticides (imidacloprid, chlorpyrifos and fipronil) decreased with the increase of treatment time.
基金supported by grants from the National Natural Science Foundation of China (31572324)the General Program of Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China (16KJB180017)+2 种基金the College Students’ Innovation and Entrepreneurship Training Program Project of Jiangsu Province, China (201813843009Y)the Jiangsu Agricultural Scientific Self-innovation Fund, China (CX[15]1053)a grant from Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘Toll-like receptors(TLRs) are the critical superfamily homologues that initiate sensing of the invasion of pathogens by the Toll pathway. As one of several intracellular nucleic acid-sensing TLRs, TLR13 is activated by an unmethylated motif present in the large ribosomal subunit of bacterial RNA. However, little attention has been paid to the function of TLR13 gene homologue from Laodelphax striatellus(designated as LsToll-13) in the immune response to rice stripe virus(RSV). Herein, LsToll-13 was cloned and characterized using RACE-PCR. Phylogenetic analysis showed that LsToll-13 was clustered with the TLR13 from six insects. Real-time PCR analysis demonstrated that the expression level of LsToll-13 was significantly reduced in L. striatellus with RSV infection compared with that in the naive strain. When the expression of LsToll-13 was significantly up-regulated at 6 h after bacterial infection, the expression of ribonucleoprotein(RNP) indicated that the RSV titer in the host insect was significantly suppressed. Upon knockdown of LsToll-13, using RNA interference(RNAi) in L. striatellus, the expression level of RNP was significantly increased with enhanced RSV accumulation, suggesting that LsToll-13 potentially protects L. striatellus from RSV infection. Taken together, our results indicated that LsToll-13 might be involved in the immune response of L. striatellus to RSV infection, and provided a new insight into further elucidating the molecular mechanisms of complex pathogen-host interactions and integrative pest management.
基金supported by the National Natural Science Foundation of China(No.32020103011,32001905,and 31871976).
文摘The endosymbiont Wolbachia manipulates host reproduction by several strategies, one of the most important of which is cytoplasmic incompatibility (CI). CI can be rescued when Wolbachia-infected males mate with females infected with the same Wolbachia strain. However, the potential rescue mechanism of CI in the small brown planthopper Laodelphax striatellus is unclear. In this study, comparative transcriptome analysis was applied to explore the effect of Wolbachia on L. striatellus eggs. A total of 1387 differentially expressed genes were identified. RNA interference of 7 Wolbachia-upregulated key planthopper genes reduced egg reproduction, suggesting that Wolbachia might improve fecundity in L. striatellus by affecting these 7 genes. Suppressing the expression of another upregulated gene, NDUFA8 (encoding NADH dehydrogenase [ubiquinone] 1 α subcomplex subunit 8-like) by RNA interference significantly increased the mortality of early embryos without affecting the number of deposited eggs. Wolbachia infection upregulated the mRNA level of NDUFA8, and dsNDUFA8 treatment of Wolbachia-infected females recreated CI-like symptoms, suggesting that NDUFA8 is associated with the rescue phenotype. Because all L. striatellus populations worldwide are infected with Wolbachia, NDUFA8 is a potential pest control target.
基金the Jiangsu Agriculture Science and Technology Innovation Fund(grant no.CX(20)1004)the Earmarked Fund for China Agriculture Research System(grant no.CARS-01).
文摘Fatty acid synthase (FAS) is a multifunctional enzyme that plays an important role in the formation of fatty acids. The fatty acids take part in many processes, such as cell signaling and energy metabolism, and in insects they are important in both cuticular hydrocarbon (CHC) formation and reproduction. Here we characterized the sequence structure and function of an FAS from the small brown planthopper (SBPH), Laodelphax striatellus. The full-length open reading frame (ORF) sequence of LsFAS1 was 7122 bp, encoding a predicted protein of 2373 amino acid residues. There were 7 functional domains in the LsFAS1 protein sequence. Gene expression screening by real-time quantitative polymerase chain reaction (RT-qPCR) showed that LsFAS1 was expressed in all developmental stages. Relative expression was highest at the 4th-instar and female adult stages. Among different tissues, the expression level of LsFAS1 in the ovary was the highest. Phylogenetic analysis showed that LsFAS1 clustered in a clade with 2 FASs from Nilaparvata lugens. Furthermore, these 3 FASs are related to cockroach BgFAS and locust LmFAS. After RNA interference-mediated knock-down, most treated insects died at eclosion. In addition, the lifespan of dsFAS1-treated female adults was shorter than that of the dsGFP-injected control, and offspring production decreased. Also, the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes decreased. Virgin females dissected at days 2 and 4 post-eclosion showed many matured oocytes in planthoppers treated with dsGFP but not with dsFAS1. These data highlight the importance of LsFAS1 in SBPH, including a role in reproduction.
基金financially supported by the National High-Tech R&D Program of China (863 Program,2007AA10Z220)National Key Technologies R&D Program during the 11th Five-Year Plan period of China(2006BAD17B06)+3 种基金the National Basic Research Program of China (973 Program, 2002CB111400)Zhejiang Provincial Key Project (2009CB119203)Zhejiang Yangtze Delta Key Sci & Tech Collaborative Program,China (2004E60055)Jiaxing City Key Sci & Tech Project, China (2005AZ3002)
文摘To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper (SBPH) Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral (RSV) disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics (AUCPD or planthopper-day accumulation) or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.
基金This study was supported by the National Natural Science Foundation of China(31871976)as well as by a grant-in-aid for Joint Research(2017-AH-04)from the NJAU-MSU Asia-Hub Project.
文摘Bacteria symbionts in herbivores play an important role in host biology and ecology,and are affected by environmental factors such as temperature,diet,habitat,antibiotics and so on.However,the effects of antibiotics on the microbiome of the small brown planthopper Laodelphax striatellus(SBPH)remain unclear.Here,we studied the effects of tetracycline on the diversity and composition of bacterial colonies in different tissues of SBPH using high throughput sequencing of 16S ribosomal RNA amplicons.Our results show that Proteobacteria,Firmicutes,Bacteroidetes,Actinobacteria were most abundant in SBPH,and the genera Asaia and Wolbachia were most abundant in all body parts of SBPH.Antibiotic treatment had persistent effects on the composition of the SBPH microbiome.Tetracycline depleted the population of Firmicutes,Bacteroidetes,Tenericutes and Fusobacteria,and nearly 100%eliminated Wolbachia,Bacteroides and Abiotrophia in SBPH.Together,these results suggest that antibiotic exposure affects the bacteria symbionts of different body parts in SBPH and will facilitate future studies of the bacterial symbionts of arthropod hosts.
文摘Ecdysteroid hormone 20-hydroxyecdysone plays fundamental roles in in- sect postembryonic development and reproduction. Several cytochrome P450 mono- oxygenases (CYPs), encoded by the Halloween genes, have been documented to be involved in ecdysteroidogenesis in representative insects in Diptera, Lepidoptera and Orthoptera. Here the putative Halloween gene Phantom (Phm, cyp306al) from a hemipteran insect species, the small brown planthopper Laodelphax striatellus, was cloned. LsPHM shows five insect conserved P450 motifs, that is, Helix-C, Helix-I, Helix-K, PERF and heme- binding motifs. Temporal and spatial expression patterns of LsPhm were evaluated by quantitative polymerase chain reaction. Through the fourth-instar and the early fifth-instar stages, LsPhm showed two expression peaks in day 2 and days 4-5 fourth-instar nymphs, and three troughs in day 1 and 3 fourth instars and day 1 fifth instars. On day 5 of the fourth-instar nymphs, LsPhm clearly had a high transcript level in the thorax where the prothoracic glands were located. Dietary introduction of double-stranded RNA (dsRNA) of LsPhm at the nymph stage successfully knocked down the target gene, decreased expres- sion level ofecdysone receptor (LsEcR) gene and caused a higher nymphal mortality rate and delayed development. Ingestion of 20-hydroxyecdysone on LsPhm-dsRNA-exposed nymphs did not increase LsPhm expression level, but almost completely rescued the LsEcR mRNA level, and relieved the negative effects on survival and development. Thus, our data suggest that the putative LsPhm encodes a ftmctional 25-hydroxylase that catalyzes the biosynthesis of ecdysteroids in L. striatellus.
文摘Rice stripe virus(RSV)is the causative agent of rice stripe disease and is completely dependent on insect vectors for its plant-to-plant transmission.Laodelphax striatellus is the major insect vector for RSV.In this study,we explored the interactions be-tween RSV infection and L.striatellus autophagy,a potential intrinsic antiviral mechanism in insects.We found that L.striatellus autophagic activity did not affect RSV infection;however,the autophagy related-8(Atg8)gene significantly enhanced virus infection.Dur-ing RSV initial infection within the L.striatellus midgut,silencing of Atg8 expression significantly decreased the phosphorylation of c-Jun N-terminal kinase(p-JNK);however,when RSV infection is absent,silencing of Atg8 did not alter p-JNK levels.Thesc results indicated that Atg8 might activate the JNK machinery by allowing more virus infection into cells.We further revealed that Atg8-deficiency significantly decreased RSV accumu-lation on the surface of the insect midgut epithelial cells,suggesting a receptor trafficking function of the y-aminobutyric acid receptor-associated protein family.Using the RSV ovary entry as a model,in which vitellogenin receptor(V gR)mediates RSV cell entry,we clarified that Atg8-deficiency decreased the abundance of V gR localizing on the cytomem-brane and disturbed the attachment of RSV in the germarium zones.Collectively,these results revealed an autophagy-independent function of L.striatellus Atg8 that enhances RSV initial infection by increasing virus attachment on the infection sites.
文摘Small brown planthopper, Laodelphax striatellus (Fall6n) numbers usually drop sharply in the summer and revive quickly in the autumn. However, it is unclear whether and how the high temperature plays a role in this process. The effects of durations of heat exposure (33~C) on life-history traits were examined here. Exposure of adults for 1 day during the oviposition stage led to a very low survival of nymphs. The average longevity ofL. striatellus exposed for 1-31 days from oviposition was significantly longer than that of the control (27℃). Short-term (1-5 days) heat exposure of the third instar nymphs did not significantly influence eclosion, but exposure of the fourth instar nymphs significantly increased eclosion. Lifespan from egg to adult was significantly lengthened when the third instar nymphs were exposed to heat for 2-15 days, or the fourth instar were exposed for 10 days. The preoviposition period was prolonged by heat exposure of the third or fourth instar nymphs. Short-term heat exposure of less than 3 days of the third or fourth instar nymphs did not restrict fecundity, but when the exposure duration exceeded 5 days the total eggs per female and hatchability decreased. Exposure to high temperature increased the brachypter rate of adults. In summary, low survival and slowing development under heat exposure resulted in population decline in the summer, and the relatively high fecundity and brachypter rate led to quick revival in autumn. Temperature in the summer determines the rise and fall in numbers ofL. striatellus.
文摘The virus disease threatening wheat production in Hulunbcir District of Inner - Mongolia was identified as NCMV (Northern Cereal Mosaic Virus) or WRSV (Wheat Rosette Stunt Virus) by tests of host range, transmission, virus particle and scrology. The main vector for spreading the virus is planthopper, Laodelphax striatellus (Fallen), which overwinters in the stubbles of wheat underground. The overwintered virulifcrous nymphs emerged in late April is responsible for the early infection of the disease. Agropyron repens, an important perennial weed in cultivated regions, is also an important wild host of the virus and its vector. Severe loss is induced when wheat is infected before 3 - leaf stage. The disease incidence could be predicted by a model with the population and virulifcrous rate of overwintered vectors as independent variables.
基金This work was supported by the National Natural Science Foundation of China(No.31672035 and 31871976)the startup grant from Nanjing Agricultural University(No.804015 and 80900224).
文摘Rice planthoppers are notorious plant sap-feeding pests which cause serious damage.While several microbes in rice planthoppers have been broadly characterized,the abundance and diversity of bacteria and fungi in field planthoppers are largely unknown.This study investigated the bacterial and fungal community compositions of Chinese wild rice planthoppers Laodelphax striatellus and Sogatella furcifera using parallel 16S rRNA gene amplicon and internal transcribed space region sequencing.The bacteria varied sig-nificantly between the species and were partitioned significantly by sex,tissues and host environments in each species.The majority of bacteria were affiliated with the genera Wol-bachia,Cardinium,Rickettsia and Pantoea.The abundance of Wolbachia was negatively correlated with that of Cardinium in both planthopper species.Compared with bacteria,the abundance and diversity of fiungi did not differ between sexes but both were enriched in the gut.The bacterial community as a whole showed no significant correlation with the fungal community.The majority of fungi were related to Sarocldium,Alternaria,Malasseria,Aspergillus and Curvularia.A phylogenetic analysis revealed that these fungi were closely related to botanic symbionts or pathogens.Our results provide novel insights into the bacteria and fungi of rice planthoppers.