To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the libra...To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DNA and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.展开更多
Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored...Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored the possible role of baterial symbionts of seagrasses Thalassia hemprichii, and Enhalus acoroides, which were successfully screened for antifouling activity against marine biofilm-forming bacteria isolated from the surrounding colonies of seagrasses. Bacterial symbionts were isolated and tested against biofilm-forming bacteria resulted in 4 bacterial symbionts capable of inhibiting the growth biofilm-forming isolates. Molecular identification based on 16S rRNA gene sequences revealed that the active bacterial symbionts belonged to the members of the genera Bacillus and Virgibacillus. Further tests of the crude extracts of the active bacterial symbionts supported the potential of these symbionts as the alternative source of environmentally friendly marine antifoulants.展开更多
The microbes associated with sponges play important roles in the nitrogen cycle of the coral reefs ecosystem,e.g.,nitrification,denitrification,and nitrogen fixation.However,the whole nitrogen-cycling network has rema...The microbes associated with sponges play important roles in the nitrogen cycle of the coral reefs ecosystem,e.g.,nitrification,denitrification,and nitrogen fixation.However,the whole nitrogen-cycling network has remained incomplete in any individual sponge holobiont.In this study,454 pyrosequencing of the 16S rRNA genes revealed that the sponge Spheciospongia vesparium from the South China Sea has a unique bacterial community(including 12 bacterial phyla),dominated particularly by the genus Shewanella(order Alteromonadales).A total of 10 functional genes,nifH,amoA,narG,napA,nirK,norB,nosZ,ureC,nrfA,and gltB,were detected in the microbiome of the sponge S.vesparium by gene-targeted analysis,revealing an almost complete nitrogen-cycling network in this sponge.Particularly,bacterial urea utilization and the whole denitrification pathway were highlighted.MEGAN analysis suggests that Proteobacteria(e.g.,Shewanella)and Bacteroidetes(e.g.,Bizionia)are probably involved in the nitrogen cycle in the sponge S.vesparium.展开更多
The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f.(an endangered leguminous tree)using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium ass...The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f.(an endangered leguminous tree)using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium associated with native populations of P.santalinus.The native arbuscular mycorrhizal fungi isolated from P.santalinus soils were identifi ed as(1)Glomus fasciculatum;(2)Glomus geosporum;and Glomus aggregatum.A nitrogenfi xing microbial symbiont was isolated from the root nodules of P.santalinus and identifi ed as Rhizobium aegyptiacum by 16s rRNA gene sequencing.These microbial symbionts were inoculated individually and in combination into P.santalinus seedling roots.After 90 days,growth and biomass had improved compared with uninoculated controls.Shoot and root lengths,number of leaves,stem circumference,number of root nodules,biomass,nutrient uptake and seedling quality index were signifi cantly increased by a combined inoculation of arbuscular mycorrhizal fungi+Rhizobium aegyptiacum.It was concluded that native microbial symbionts positively infl uenced P.santalinus seedling growth which will be helpful for successful fi eld establishment.展开更多
The ubiquitous incorporation of plastics into daily life,coupled with inefficient recycling practices,has resulted in the accumulation of millions of metric tons of plastic waste,that poses a serious threat to the Ear...The ubiquitous incorporation of plastics into daily life,coupled with inefficient recycling practices,has resulted in the accumulation of millions of metric tons of plastic waste,that poses a serious threat to the Earth's sustainability.Plastic pollution,a global problem,disrupts the ecological balance and endangers various life forms.Efforts to combat plastic pollution are underway,with a promising avenue being biological degradation facilitated by certain insects and their symbiotic gut microorganisms,particularly bacteria.This review consolidates existing knowledge on plastic degradation by insects and their influence on gut microbiota.Additionally,it delves into the potential mechanisms employed by insects in symbiosis with gut bacteria,exploring the bioconversion of waste plastics into value-added biodegradable polymers through mineralization.These insights hold significant promise for the bio-upcycling of plastic waste,opening new horizons for future biomanufacturing of high-value chemicals from plastic-derived compounds.Finally,we weigh the pros and cons of future research endeavors related to the bioprospection of plastic-degrading bacteria from underexplored insect species.We also underscore the importance of bioengineering depolymerases with novel characteristics,aiming for their application in the remediation and valorization of waste plastics.展开更多
Anastrepha fraterculus is a significant fruit fly pest in Argentina and other South American countries. Previous studies showed the key role of gut bacteria in the protection and nutrient assimilation of fruit flies, ...Anastrepha fraterculus is a significant fruit fly pest in Argentina and other South American countries. Previous studies showed the key role of gut bacteria in the protection and nutrient assimilation of fruit flies, particularly the importance of the biological fixation of nitrogen (diazotrophy). The presence of diazotrophic bacteria in A. fraterculus sp. 1 has been demonstrated through molecular, culture-independent methods. This study is aimed to characterize the composition and diversity of culturable gut bacteria of A. fraterculus sp. 1 males from different origins, and explore their metabolic roles, focusing on diazotrophic bacteria. Three male groups were studied: wild-caught (WW), lab-reared from wild larvae (WL), and lab-colony raised (LL). Gut bacteria were collected and characterized via 16S rRNA gene sequencing, with potential diazotrophs screened using selective media (SIL and NFb). Phylogenetic analysis of 16S rRNA gene mapped potential diazotrophs across the bacterial collection, while biochemical profiling and ARDRA (Amplified rDNA Restriction Analysis) were used to quickly differentiate diazotrophic bacteria. PCR testing for the nifH gene, associated with nitrogen fixation, was also performed. Bacterial diversity was highest in WW, followed by WL, and lowest in LL. In LL and WL, Enterobacter was the most frequent genus, while Klebsiella dominated in WW. Among the 20 SIL+ isolates identified, 10 came from WW, 9 from WL, and 1 from LL. One of these isolates (Enterobacter sp.) was tested as a supplement to the adult diet, without showing a beneficial effect on males pheromone calling behavior. Three isolates were also NFb+;two had the nifH gene. ARDRA was effective for rapid diazotroph discrimination. These findings highlight the potential of gut symbiotic bacteria in eco-friendly pest management strategies like the sterile insect technique (SIT). By using diazotrophic bacteria, protein requirements in artificial diets could be reduced, cutting costs and improving the affordability of SIT programs.展开更多
Microbial symbionts are essential or important partners to phloem-feeding insects.Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain ...Microbial symbionts are essential or important partners to phloem-feeding insects.Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts.In this study,using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex,which harbors the primary symbiont"Candidatus Portiera aleyrodidarum"and two secondary symbionts"Candidatus Hamiltonella defensa"and Rickettsia.Neither the primary nor the secondary symbionts were completely depleted in the adults(F0)that fed for 48 h on a diet treated with rifampicin at concentrations of 1100/zg/mL.However,both the primary and secondary symbionts were nearly completely depleted in the offspring(F 1)of the rifampicin-treated adults.Although the F1 adults produced some eggs(F2),most of the eggs failed to hatch and none of them reached the second instar,and consequently the rifampicin-treated whitefly colony vanished at the F2 generation.Interestingly,quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies,the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts.Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects ofrifampicin on host fitness were expressed when the females were treated by the antibiotic,and whether males were treated or not by the antibiotic had little contribution to the negative effects.These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies.However,the extinction of the whitefly colony at the second generation after rifampicin treatment indicates the potential of the antibiotic as a control agent of the whitefly pest.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
Ciliates are a dominant group in the marine sediment microecosystem,and their interactions with symbiotic prokaryotes are important for understanding the adaptation mechanisms of marine benthic eukaryotes.However,the ...Ciliates are a dominant group in the marine sediment microecosystem,and their interactions with symbiotic prokaryotes are important for understanding the adaptation mechanisms of marine benthic eukaryotes.However,the microbial communities(microbiome)associated with most benthic ciliates and the taxonomic attributes of the dominant symbiotic bacteria are unclear.In this study,we focused on Paraspathidium apofuscum,a ciliate prevalent in marine benthic environments,and comprehensively explored the diversity and cellular location of the microbiomes in two P.apofuscum isolates using single-cell-based full-length16S rRNA amplicon sequencing,phylogenetic analysis,and fluorescence in situ hybridization.The results showed that the P.apofuscum cell surface carried a highly diverse microbiome whose cellular localization was consistent with the positions of the ciliate's somatic dikinetids.The dominant genera in the microbiome,Pseudoalteromonas,Halobacteriovorax and Oceaniserpentilla,were associated with unicellular eukaryotes.In particular,Pseudoalteromonas likely uses ciliate-secreted metabolites as nutrients and plays a role in host physical protection or pathogen resistance.Halobacteriovorax and Oceaniserpentilla are newly discovered or rare bacterial genera innovatively found to have ecological niches in symbiosis with benthic ciliates.Comparison analysis indicates that the microbiomes associated with benthic ciliates display species and population specificity,which are attributed to several factors such as environmental physicochemical properties,host physiological states,and interactions among associated bacteria.This study provides important insights into the environmental adaptation of eukaryotes through a symbiotic mechanism in the marine benthic environment.展开更多
Ten marine sponge species from Rameswaram,southern India were studied for their filamentous fungal symbionts.The results suggest that fungal symbionts of marine sponges are hyperdiverse.Genera such as Acremonium,Alter...Ten marine sponge species from Rameswaram,southern India were studied for their filamentous fungal symbionts.The results suggest that fungal symbionts of marine sponges are hyperdiverse.Genera such as Acremonium,Alternaria,Aspergillus,Cladosporium,Fusarium and Penicillium were frequently isolated;no true marine fungal species were present.Species of Aspergillus were dominant and co-dominant in all the sponges screened.The fungal isolates produced antialgal,antifungal,antioxidant,antibiotic,antiinsect metabolites.A few fungi produced acetylcholinesterase inhibitors.展开更多
Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological...Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological activities of symbiont-derived secondary metabolites commonly referred to as "natural products", and highlights that symbiotic microbes represent an underexplored reservoir of natural products with unique scaffolds and promising significance in managing human healthcare and agricultural production.展开更多
Nutritional mutualism between insects and symbiotic bacteria is widespread.The various sap-feeding whitefly species within the Bemisia tabaci complex associate with the same obligate symbiont(Portiera)and multiple sec...Nutritional mutualism between insects and symbiotic bacteria is widespread.The various sap-feeding whitefly species within the Bemisia tabaci complex associate with the same obligate symbiont(Portiera)and multiple secondary symbionts.It is often assumed that some of the symbionts residing in the whiteflies play crucial roles in the nutritional physiology of their insect hosts.Although effort has been made to understand the functions of the whitefly symbionts,the metabolic complementarity offered by these symbionts to the hosts is not yet well understood.We examined two secondary symbionts,Arsenophonus and Wolbachia,in two species of the B.tabaci whitefly complex,provisionally named as Asia II 3 and China 1.Genomic sequence analyses revealed that Arsenophonus and Wolbachia retained genes responsible for the biosynthesis of B vitamins.We then conducted transcriptomic surveys of the bacteriomes in these two species of whiteflies together with that in another species named MED of this whitefly complex previously reported.The analyses indicated that several key genes in B vitamin syntheses from the three whitefly species were identical.Our findings suggest that,similar to another secondary symbiont Hamiltonella,Arsenophonus and Wolbachia function in the nutrient provision of host whiteflies.Although phylogenetically distant species of symbionts are associated with their respective hosts,they have evolved and retained similar functions in biosynthesis of some B vitamins.Such metabolic complementarity between whiteflies and symbionts represents an important feature of their coevolution.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
Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt...Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt,was recorded in a species of notorious pest whitefly,tentatively named as Asia II 1,from the Bemisia tabaci complex.The role of this Rickettsia in the biology of its host is unknown.Here we investigated the impact of RiTBt on the performance and virus transmission capacity of Asia II 1.RiTBt did not significantly affect the life history parameters of the whitefly when the host insect was reared on tobacco,tomato,and cotton,three host plants with relatively low,medium and high suitability to the whitefly.Intriguingly,RiTBt slightly enhanced whitefly transmission of cotton leaf curl Multan virus(CLCuMuV),a virus that is transmitted by the whitefly in the field and has caused extensive damage to cotton production.Specifically,compared with whiteflies without RiTBt,following a 48 h virus acquisition whiteflies with RiTBt had higher titer of virus and showed higher efficiency of virus transmission.A rickettsial secretory protein BtR242 was identified as a putative virus-binding protein,and was observed to interact with the coat protein of CLCuMuV in vitro.Viral infection of the whitefly downregulated gene transcript levels of the BtR242 gene.These observations indicate that RiTBt has limited impact on the biology of the Asia II 1 whitefly,and whether this symbiont has functions in the biology of other host whiteflies warrants future investigation.展开更多
We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial ...We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial symbionts deposited with feees or regur-gitated by feeding flies.We allowed laboratory-reared black blow flies,Phormia regina(Meigen),to feed and de fecate on bacterial Luria-Bertani medium solidified with agar,and isolated seven morphologically distinct bacterial colonies.We identified these us-ing matrix-assisted laser desorption/ionization mass spectrometry and sequencing of the 165 rRNA gene.In two-choice laboratory experiments,traps baited with cultures of Pro-teus mirabilis Hauser,Morganella morganii subsp.sibonii Jensen,or Serratia marcescens Bizio,captured significantly more flies than corresponding control jars baited with tryptic soy agar only.A mixture of seven bacterial strains as a trap bait was more attractive to flies than a single bacterial isolate(M.m.siboni).In a field experiment,traps baited with agar cultures of P:mirabilis and M.m siboni in combination captured significantly more flies than lraps baited with either bacterial isolate alone or the agar control.As evident by gas chromatography-mass spectrometry,the odor profiles of bacterial isolates differ,which may explain the additive effect of bacteria to the attractiveness of bacterial trap baits.As"generalist bacteria,"P mirabilis and M.m.sibonii growing on animal protein(beef liver)or plant protein(tofu)are similarly effective in attracting flies.Bacteria-derived airborne semiochemicals appear to mediate foraging by flies and to inform their feeding and oviposition decisions.展开更多
Microbial lysis of dimethylsulfoniopropionate(DMSP)is a key step in marine organic sulfur cycling and has been recently demonstrated to play an important role in mediating interactions between bacteria,algae,and zoopl...Microbial lysis of dimethylsulfoniopropionate(DMSP)is a key step in marine organic sulfur cycling and has been recently demonstrated to play an important role in mediating interactions between bacteria,algae,and zooplankton.To date,microbes that have been found to lyse DMSP are largely confined to free‐living and surface‐attached bacteria.In this study,we report for the first time that a symbiont(termed“Rhodobiaceae bacterium HWgs001”)in the gill of the marine scallop Argopecten irradians irradians can lyse and metabolize DMSP.Analysis of 16S rRNA gene sequences suggested that HWgs001 accounted for up to 93%of the gill microbiota.Microscopic observations suggested that HWgs001 lived within the gill tissue.Unlike symbionts of other bivalves,HWgs001 belongs to Alphaproteobacteria rather than Gammaproteobacteria,and no genes for carbon fixation were identified in its small genome.Moreover,HWgs001 was found to possess a dddP gene,responsible for the lysis of DMSP to acrylate.The enzymatic activity of dddP was confirmed using the heterologous expression,and in situ transcription of the gene in scallop gill tissues was demonstrated using reverse‐transcription PCR.Together,these results revealed a taxonomically and functionally unique symbiont,which represents the first‐documented DMSP‐metabolizing symbiont likely to play significant roles in coastal marine ecosystems.展开更多
基金This work was supported by High Tech R&D Program of China(Grant Nos.2002AA628130 and 2003AA624020)the National Natural Science Foundation of China(30171102)+2 种基金the Fund for Cheung Kong Scholar from the Cheung Kong Scholar Program of Ministry of Education of Chinathe Fund from the Natural Science Foundation of Shandong Province(No.Z2001C01)the High Tech R&D Program of Shandong Province(No.0121100107).The authors would like to thank Professor Li Jinhe of Institute of 0ceanology,Chinese Academy of Sciences,for the identification of the sponge.
文摘To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DNA and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.
文摘Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored the possible role of baterial symbionts of seagrasses Thalassia hemprichii, and Enhalus acoroides, which were successfully screened for antifouling activity against marine biofilm-forming bacteria isolated from the surrounding colonies of seagrasses. Bacterial symbionts were isolated and tested against biofilm-forming bacteria resulted in 4 bacterial symbionts capable of inhibiting the growth biofilm-forming isolates. Molecular identification based on 16S rRNA gene sequences revealed that the active bacterial symbionts belonged to the members of the genera Bacillus and Virgibacillus. Further tests of the crude extracts of the active bacterial symbionts supported the potential of these symbionts as the alternative source of environmentally friendly marine antifoulants.
基金Financial support from the National Natural Science Foundation of China(NSFC)(Nos.31861143020,41776138)was used to conduct this research and is greatly appreciated.
文摘The microbes associated with sponges play important roles in the nitrogen cycle of the coral reefs ecosystem,e.g.,nitrification,denitrification,and nitrogen fixation.However,the whole nitrogen-cycling network has remained incomplete in any individual sponge holobiont.In this study,454 pyrosequencing of the 16S rRNA genes revealed that the sponge Spheciospongia vesparium from the South China Sea has a unique bacterial community(including 12 bacterial phyla),dominated particularly by the genus Shewanella(order Alteromonadales).A total of 10 functional genes,nifH,amoA,narG,napA,nirK,norB,nosZ,ureC,nrfA,and gltB,were detected in the microbiome of the sponge S.vesparium by gene-targeted analysis,revealing an almost complete nitrogen-cycling network in this sponge.Particularly,bacterial urea utilization and the whole denitrification pathway were highlighted.MEGAN analysis suggests that Proteobacteria(e.g.,Shewanella)and Bacteroidetes(e.g.,Bizionia)are probably involved in the nitrogen cycle in the sponge S.vesparium.
基金a research project(No.IFGTB/NFRP 168)of the Indian Council of Forestry Research and Education,Dehra Dun.
文摘The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f.(an endangered leguminous tree)using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium associated with native populations of P.santalinus.The native arbuscular mycorrhizal fungi isolated from P.santalinus soils were identifi ed as(1)Glomus fasciculatum;(2)Glomus geosporum;and Glomus aggregatum.A nitrogenfi xing microbial symbiont was isolated from the root nodules of P.santalinus and identifi ed as Rhizobium aegyptiacum by 16s rRNA gene sequencing.These microbial symbionts were inoculated individually and in combination into P.santalinus seedling roots.After 90 days,growth and biomass had improved compared with uninoculated controls.Shoot and root lengths,number of leaves,stem circumference,number of root nodules,biomass,nutrient uptake and seedling quality index were signifi cantly increased by a combined inoculation of arbuscular mycorrhizal fungi+Rhizobium aegyptiacum.It was concluded that native microbial symbionts positively infl uenced P.santalinus seedling growth which will be helpful for successful fi eld establishment.
基金supported by the National Natural Science Foundation of China(32250410285)the National Key R&D Program of China(2023YFC3403600)Foreign Expert Program,Ministry of Science and Technology(MoST)of China(WGXZ2023020L).
文摘The ubiquitous incorporation of plastics into daily life,coupled with inefficient recycling practices,has resulted in the accumulation of millions of metric tons of plastic waste,that poses a serious threat to the Earth's sustainability.Plastic pollution,a global problem,disrupts the ecological balance and endangers various life forms.Efforts to combat plastic pollution are underway,with a promising avenue being biological degradation facilitated by certain insects and their symbiotic gut microorganisms,particularly bacteria.This review consolidates existing knowledge on plastic degradation by insects and their influence on gut microbiota.Additionally,it delves into the potential mechanisms employed by insects in symbiosis with gut bacteria,exploring the bioconversion of waste plastics into value-added biodegradable polymers through mineralization.These insights hold significant promise for the bio-upcycling of plastic waste,opening new horizons for future biomanufacturing of high-value chemicals from plastic-derived compounds.Finally,we weigh the pros and cons of future research endeavors related to the bioprospection of plastic-degrading bacteria from underexplored insect species.We also underscore the importance of bioengineering depolymerases with novel characteristics,aiming for their application in the remediation and valorization of waste plastics.
基金Funding was provided by FAO/IAEA contract 22515(CRP D42017),PICT-2019-04141,PIP-CONICET 0039PI USAL 2022-80020210100018.
文摘Anastrepha fraterculus is a significant fruit fly pest in Argentina and other South American countries. Previous studies showed the key role of gut bacteria in the protection and nutrient assimilation of fruit flies, particularly the importance of the biological fixation of nitrogen (diazotrophy). The presence of diazotrophic bacteria in A. fraterculus sp. 1 has been demonstrated through molecular, culture-independent methods. This study is aimed to characterize the composition and diversity of culturable gut bacteria of A. fraterculus sp. 1 males from different origins, and explore their metabolic roles, focusing on diazotrophic bacteria. Three male groups were studied: wild-caught (WW), lab-reared from wild larvae (WL), and lab-colony raised (LL). Gut bacteria were collected and characterized via 16S rRNA gene sequencing, with potential diazotrophs screened using selective media (SIL and NFb). Phylogenetic analysis of 16S rRNA gene mapped potential diazotrophs across the bacterial collection, while biochemical profiling and ARDRA (Amplified rDNA Restriction Analysis) were used to quickly differentiate diazotrophic bacteria. PCR testing for the nifH gene, associated with nitrogen fixation, was also performed. Bacterial diversity was highest in WW, followed by WL, and lowest in LL. In LL and WL, Enterobacter was the most frequent genus, while Klebsiella dominated in WW. Among the 20 SIL+ isolates identified, 10 came from WW, 9 from WL, and 1 from LL. One of these isolates (Enterobacter sp.) was tested as a supplement to the adult diet, without showing a beneficial effect on males pheromone calling behavior. Three isolates were also NFb+;two had the nifH gene. ARDRA was effective for rapid diazotroph discrimination. These findings highlight the potential of gut symbiotic bacteria in eco-friendly pest management strategies like the sterile insect technique (SIT). By using diazotrophic bacteria, protein requirements in artificial diets could be reduced, cutting costs and improving the affordability of SIT programs.
基金financially supported by the National Basic Research Program of China(Project No.2013 CB 127604)the National Natural Science Foundation of China(Project No.31390421).
文摘Microbial symbionts are essential or important partners to phloem-feeding insects.Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts.In this study,using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex,which harbors the primary symbiont"Candidatus Portiera aleyrodidarum"and two secondary symbionts"Candidatus Hamiltonella defensa"and Rickettsia.Neither the primary nor the secondary symbionts were completely depleted in the adults(F0)that fed for 48 h on a diet treated with rifampicin at concentrations of 1100/zg/mL.However,both the primary and secondary symbionts were nearly completely depleted in the offspring(F 1)of the rifampicin-treated adults.Although the F1 adults produced some eggs(F2),most of the eggs failed to hatch and none of them reached the second instar,and consequently the rifampicin-treated whitefly colony vanished at the F2 generation.Interestingly,quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies,the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts.Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects ofrifampicin on host fitness were expressed when the females were treated by the antibiotic,and whether males were treated or not by the antibiotic had little contribution to the negative effects.These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies.However,the extinction of the whitefly colony at the second generation after rifampicin treatment indicates the potential of the antibiotic as a control agent of the whitefly pest.
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supported by the National Natural Science Foundation of China(Nos.42176163 and 31970398)。
文摘Ciliates are a dominant group in the marine sediment microecosystem,and their interactions with symbiotic prokaryotes are important for understanding the adaptation mechanisms of marine benthic eukaryotes.However,the microbial communities(microbiome)associated with most benthic ciliates and the taxonomic attributes of the dominant symbiotic bacteria are unclear.In this study,we focused on Paraspathidium apofuscum,a ciliate prevalent in marine benthic environments,and comprehensively explored the diversity and cellular location of the microbiomes in two P.apofuscum isolates using single-cell-based full-length16S rRNA amplicon sequencing,phylogenetic analysis,and fluorescence in situ hybridization.The results showed that the P.apofuscum cell surface carried a highly diverse microbiome whose cellular localization was consistent with the positions of the ciliate's somatic dikinetids.The dominant genera in the microbiome,Pseudoalteromonas,Halobacteriovorax and Oceaniserpentilla,were associated with unicellular eukaryotes.In particular,Pseudoalteromonas likely uses ciliate-secreted metabolites as nutrients and plays a role in host physical protection or pathogen resistance.Halobacteriovorax and Oceaniserpentilla are newly discovered or rare bacterial genera innovatively found to have ecological niches in symbiosis with benthic ciliates.Comparison analysis indicates that the microbiomes associated with benthic ciliates display species and population specificity,which are attributed to several factors such as environmental physicochemical properties,host physiological states,and interactions among associated bacteria.This study provides important insights into the environmental adaptation of eukaryotes through a symbiotic mechanism in the marine benthic environment.
基金TSS and MD acknowledge the financial assistance by Department of Biotechnology(BT/PR10169/AAQ/03/376/2007),New Delhi,Government of India and Dr.G.Sivaleela,Zoological Survey of India,Chennai for identifying the sponge species.
文摘Ten marine sponge species from Rameswaram,southern India were studied for their filamentous fungal symbionts.The results suggest that fungal symbionts of marine sponges are hyperdiverse.Genera such as Acremonium,Alternaria,Aspergillus,Cladosporium,Fusarium and Penicillium were frequently isolated;no true marine fungal species were present.Species of Aspergillus were dominant and co-dominant in all the sponges screened.The fungal isolates produced antialgal,antifungal,antioxidant,antibiotic,antiinsect metabolites.A few fungi produced acetylcholinesterase inhibitors.
基金supported by the National High Technology Research and Development Program of China(2013AA092901)the National Natural Science Foundation of China(81121062,21132004,81421091)
文摘Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological activities of symbiont-derived secondary metabolites commonly referred to as "natural products", and highlights that symbiotic microbes represent an underexplored reservoir of natural products with unique scaffolds and promising significance in managing human healthcare and agricultural production.
基金supported by the National Natural Science Foundation of China(Project no.:31772173).
文摘Nutritional mutualism between insects and symbiotic bacteria is widespread.The various sap-feeding whitefly species within the Bemisia tabaci complex associate with the same obligate symbiont(Portiera)and multiple secondary symbionts.It is often assumed that some of the symbionts residing in the whiteflies play crucial roles in the nutritional physiology of their insect hosts.Although effort has been made to understand the functions of the whitefly symbionts,the metabolic complementarity offered by these symbionts to the hosts is not yet well understood.We examined two secondary symbionts,Arsenophonus and Wolbachia,in two species of the B.tabaci whitefly complex,provisionally named as Asia II 3 and China 1.Genomic sequence analyses revealed that Arsenophonus and Wolbachia retained genes responsible for the biosynthesis of B vitamins.We then conducted transcriptomic surveys of the bacteriomes in these two species of whiteflies together with that in another species named MED of this whitefly complex previously reported.The analyses indicated that several key genes in B vitamin syntheses from the three whitefly species were identical.Our findings suggest that,similar to another secondary symbiont Hamiltonella,Arsenophonus and Wolbachia function in the nutrient provision of host whiteflies.Although phylogenetically distant species of symbionts are associated with their respective hosts,they have evolved and retained similar functions in biosynthesis of some B vitamins.Such metabolic complementarity between whiteflies and symbionts represents an important feature of their coevolution.
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.
基金We thank Professor Myron Zalucki,The University of Queensland,Australia for editing the final version of the manuscript prior to submission.This work was financially supported by the National Natural Science Foundation of China(Project no.31772173).
文摘Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt,was recorded in a species of notorious pest whitefly,tentatively named as Asia II 1,from the Bemisia tabaci complex.The role of this Rickettsia in the biology of its host is unknown.Here we investigated the impact of RiTBt on the performance and virus transmission capacity of Asia II 1.RiTBt did not significantly affect the life history parameters of the whitefly when the host insect was reared on tobacco,tomato,and cotton,three host plants with relatively low,medium and high suitability to the whitefly.Intriguingly,RiTBt slightly enhanced whitefly transmission of cotton leaf curl Multan virus(CLCuMuV),a virus that is transmitted by the whitefly in the field and has caused extensive damage to cotton production.Specifically,compared with whiteflies without RiTBt,following a 48 h virus acquisition whiteflies with RiTBt had higher titer of virus and showed higher efficiency of virus transmission.A rickettsial secretory protein BtR242 was identified as a putative virus-binding protein,and was observed to interact with the coat protein of CLCuMuV in vitro.Viral infection of the whitefly downregulated gene transcript levels of the BtR242 gene.These observations indicate that RiTBt has limited impact on the biology of the Asia II 1 whitefly,and whether this symbiont has functions in the biology of other host whiteflies warrants future investigation.
文摘We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial symbionts deposited with feees or regur-gitated by feeding flies.We allowed laboratory-reared black blow flies,Phormia regina(Meigen),to feed and de fecate on bacterial Luria-Bertani medium solidified with agar,and isolated seven morphologically distinct bacterial colonies.We identified these us-ing matrix-assisted laser desorption/ionization mass spectrometry and sequencing of the 165 rRNA gene.In two-choice laboratory experiments,traps baited with cultures of Pro-teus mirabilis Hauser,Morganella morganii subsp.sibonii Jensen,or Serratia marcescens Bizio,captured significantly more flies than corresponding control jars baited with tryptic soy agar only.A mixture of seven bacterial strains as a trap bait was more attractive to flies than a single bacterial isolate(M.m.siboni).In a field experiment,traps baited with agar cultures of P:mirabilis and M.m siboni in combination captured significantly more flies than lraps baited with either bacterial isolate alone or the agar control.As evident by gas chromatography-mass spectrometry,the odor profiles of bacterial isolates differ,which may explain the additive effect of bacteria to the attractiveness of bacterial trap baits.As"generalist bacteria,"P mirabilis and M.m.sibonii growing on animal protein(beef liver)or plant protein(tofu)are similarly effective in attracting flies.Bacteria-derived airborne semiochemicals appear to mediate foraging by flies and to inform their feeding and oviposition decisions.
基金supported by the Key Research and Development Program of Shandong Province(No.2021 ZLGX03)the start-up fund from Ocean University of China(No.862101013141).
文摘Microbial lysis of dimethylsulfoniopropionate(DMSP)is a key step in marine organic sulfur cycling and has been recently demonstrated to play an important role in mediating interactions between bacteria,algae,and zooplankton.To date,microbes that have been found to lyse DMSP are largely confined to free‐living and surface‐attached bacteria.In this study,we report for the first time that a symbiont(termed“Rhodobiaceae bacterium HWgs001”)in the gill of the marine scallop Argopecten irradians irradians can lyse and metabolize DMSP.Analysis of 16S rRNA gene sequences suggested that HWgs001 accounted for up to 93%of the gill microbiota.Microscopic observations suggested that HWgs001 lived within the gill tissue.Unlike symbionts of other bivalves,HWgs001 belongs to Alphaproteobacteria rather than Gammaproteobacteria,and no genes for carbon fixation were identified in its small genome.Moreover,HWgs001 was found to possess a dddP gene,responsible for the lysis of DMSP to acrylate.The enzymatic activity of dddP was confirmed using the heterologous expression,and in situ transcription of the gene in scallop gill tissues was demonstrated using reverse‐transcription PCR.Together,these results revealed a taxonomically and functionally unique symbiont,which represents the first‐documented DMSP‐metabolizing symbiont likely to play significant roles in coastal marine ecosystems.
