Plant roots interact with diverse fungi that are essential for maintaining the productivity and sustainability of pasture ecosystems,but how these root-associated fungi(RAF)differ between forage species and how they r...Plant roots interact with diverse fungi that are essential for maintaining the productivity and sustainability of pasture ecosystems,but how these root-associated fungi(RAF)differ between forage species and how they respond to nutrient enrichment and fungicide application are not well understood.Here,we constructed an 11-year experiment involving fungicide application(with or without)nested within four levels of experimental nitrogen(N)addition treatments in an alpine pasture,and the RAF communities,root traits,tissue nutrients,and shoot biomass of two dominant forage species(Carex capillifolia and Elymus nutans)were analyzed.The RAF community composition showed striking differences between the plant species and was strongly affected by both N addition level and fungicide applications.Fungicide,but not N application,dramatically reduced the RAF richness of all functional guilds in both plant species,and fungicide also simplified the co-occurrence network of the RAF for C.capillifolia.The RAF community correlated strongly with root traits,whereas their relationships became weakened or even vanished at the level of the individual plant species.The importance of RAF to plant nutrients and productivity varied between plant species,with significant contributions in C.capillifolia but not in E.nutans.This is the first report elucidating the long-term effect of fungicides on RAF in alpine pastures,and our findings emphasize the host-specific responses of RAF community structure and function to anthropogenic disturbances.展开更多
Wheat-maize(WM)and wheat-soybean(WS)double-cropping rotation systems are predominant in the North China Plain,with implications for national agricultural output and sustainability.As rotation systems exert legacy effe...Wheat-maize(WM)and wheat-soybean(WS)double-cropping rotation systems are predominant in the North China Plain,with implications for national agricultural output and sustainability.As rotation systems exert legacy effects on soil health and crop productivity,the role of crop rotation in shaping the root-associated microbiome of the succeeding crops has emerged as a pivotal aspect of crop management research.Here,the effects of the preceding two cycles of WM and WS rotations on the recruitment and filtering of wheat root-associated bacterial communities across wheat developmental stages were investigated.Our results revealed that bacterial community diversity and composition were primarily influenced by compartment and developmental stage,while the preceding rotation systems had a slight but significant effect on wheat root-associated bacterial communities.The co-occurrence networks under WM were more complex in the wheat rhizosphere and rhizoplane,with the operational taxonomic units(OTUs)related to cellulolysis showing greater connectivity.The co-occurrence networks under WS were simple but stable in the rhizosphere and complex in the rhizoplane and endosphere,with the OTUs related to ureolysis and nitrogen fixation showing greater connectivity.While both stochastic and deterministic processes contributed to the assembly of wheat root-associated bacterial communities,the contributions of deterministic processes under WS were 19.4-38.5%higher than those under the WM rotation across the root-associated compartments,indicating the substantial impact of a soybean legacy effect on wheat root selection of microbes.Plant growthpromoting rhizobacteria with the potential to fix nitrogen,produce indole-3-acetic acid,and inhibit diseases such as Betaproteobacteriales,Azospirillales and Dyella sp.,were identified within the OTUs that were consistently enriched across all the wheat root-associated compartments and developmental stages,which were also important predictors of wheat yield.This study elucidates the role of crop rotation in modulating the dynamics of crop root-associated bacterial communities,and underscores the potential of targeted microbiome manipulation for optimizing wheat production and enhancing soil health.展开更多
Root-associated microbes play an essentialrole in mediating plant growth,health,and habitat adaptability.However,it is unknown which microbial taxa help develop host fitness and how habitats shape root-associated micr...Root-associated microbes play an essentialrole in mediating plant growth,health,and habitat adaptability.However,it is unknown which microbial taxa help develop host fitness and how habitats shape root-associated microbial assembly patterns.As an endemic species of subalpine forests in western Sichuan,China,Minjiang fir(Abies fargesii var.faxoniana)is dominant on cold-shaded northwestern slopes while absent on warm sunlit southwestern slopes.In this study,fungal and bacterial communities were investigated in three spatial compartments(endosphere,rhizosphere,and bulk soil)associated with Minjiang fir saplings on a cold-shaded northwestern slope and a warm sunlit southwestern slope.Habitats differentiated the microbial communities regardless of the spatial compartment and microbial taxa.Slope aspect variations caused shifts in root-associated(rhizosphere and endosphere)microbial compositions.Compared with the southwestern slope,the cold-shaded northwestern slope harbored a higher abundance of the growth-promoting bacteria Burkholderia and ectomycorrhizal fungi Cortinarius and Piloderma.The slope aspect had stronger effects on fungal diversity than bacterial diversity,with higher fungal endemism and lower bacterial endemism.Slope aspect variations were the dominant drivers of root-associated microbial communities,with lower contribution by soil properties and higher contribution by plant traits on the northwestern slope.Findings from this study could improve the understanding of plant habitat adaptability from the perspective of microbial community assembly.It is suggested that forest management should consider root-associated microbiomes for enhancing species fitness and habitat adaptability.展开更多
Root-associated microbes are critical for plant growth and nutrient acquisition. However, scant information exists on optimizing communities of beneficial root-associated microbes or the mechanisms underlying their in...Root-associated microbes are critical for plant growth and nutrient acquisition. However, scant information exists on optimizing communities of beneficial root-associated microbes or the mechanisms underlying their interactions with host plants. In this report, we demonstrate that rootassociated microbes are critical influencers of host plant growth and nutrient acquisition. Three synthetic communities(SynComs) were constructed based on functional screening of 1,893 microbial strains isolated from root-associated compartments of soybean plants. Functional assemblage of SynComs promoted significant plant growth and nutrient acquisition under both N/P nutrient deficiency and sufficiency conditions.Field trials further revealed that application of SynComs stably and significantly promoted plant growth, facilitated N and P acquisition, and subsequently increased soybean yield. Among the tested communities, SynCom1 exhibited the greatest promotion effect, with yield increases of up to 36.1% observed in two field sites. Further RNA-seq implied that SynCom application systemically regulates N and P signaling networks at the transcriptional level, which leads to increased representation of important growth pathways, especially those related to auxin responses. Overall,this study details a promising strategy for constructing SynComs based on functional screening,which are capable of enhancing nutrient acquisition and crop yield through the activities of beneficial root-associated microbes.展开更多
Phosphorus （P） deficiency is a major limitation for plant growth and development. Among the wide set of responses to cope with low soil P, plants increase their level of intracellular and secreted acid phosphatases ...Phosphorus （P） deficiency is a major limitation for plant growth and development. Among the wide set of responses to cope with low soil P, plants increase their level of intracellular and secreted acid phosphatases （APases）, which helps to catalyze inorganic phosphate （Pi） hydrolysis from organophosphates, in this study we characterized the rice （Oryza sativa） purple acid phosphatase 10a （OsPAPIOa）. OsPAPIOa belongs to group la of purple acid phosphatases （PAPs）, and clusters with the principal secreted PAPs in a variety of plant species including Arabidopsis. The transcript abundance of OsPAPIOa is specifically induced by Pi deficiency and is controlled by OsPHR2, the central transcription factor controlling Pi homeostasis. In gel activity assays of root and shoot protein extracts, it was revealed that OsPAPIOa is a major acid phosphatase isoform induced by Pi starvation. Constitutive overexpression of OsPAPIOa results in a significant increase of phosphatase activity in both shoot and root protein extracts. In vivo root 5-bromo.4-chloro-3-indolyl-phosphate （BCIP） assays and activity measurements on external media showed that OsPAPIOa is a root-associated APase. Furthermore, overexpression of OsPAPIOa significantly improved ATP hydrolysis and utilization compared with wild type plants. These results indicate that OsPAPIOa can potentially be used for crop breeding to improve the efficiency of P use.展开更多
Soil-derived microbiota associated with plant roots are conducive to plant growth and stress resistance.However,the spatio-temporal dynamics of microbiota in response to organochlorine pollution during the unstable ve...Soil-derived microbiota associated with plant roots are conducive to plant growth and stress resistance.However,the spatio-temporal dynamics of microbiota in response to organochlorine pollution during the unstable vegetative growth phase of rice is not well understood.In this study,we focused on the rice(Oryza sativa L.)microbiota across the bulk soil,rhizosphere and endosphere compartments during the vegetative growth phase in two different soils with and without lindane pollutant.The results showed that the factors of growth time,soil types and rhizo-compartments had significant influence on the microbial communities of rice,while lindane mostly stimulated the construction of endosphere microbiota at the vegetative phase.Active rice root-soil-microbe interactions induced an inhibition effect on lindane removal at the later vegetative growth phase in rice-growth-dependent anaerobic condition,likely due to the root oxygen loss and microbial mediated co-occurring competitive electron-consuming redox processes in soils.Each rhizocompartment owned distinct microbial communities,and therefore,presented specific ecologically functional categories,while the moderate functional differences were also affected by plants species and residual pollution stress.This work revealed the underground micro-ecological process of microbiota and especially their potential linkage to the natural attenuation of residual organochlorine such as lindane.展开更多
To improve crop yields,global food production needs sustainable agronomic tools like Plant Growth-Promoting Rhizobacteria(PGPR).Region-adapted PGPR strains are crucial to increasing peanut production.Argentina is the ...To improve crop yields,global food production needs sustainable agronomic tools like Plant Growth-Promoting Rhizobacteria(PGPR).Region-adapted PGPR strains are crucial to increasing peanut production.Argentina is the seventh-largest peanut producer,and Cordoba is the main region with 250,000 ha(75%of the total sowing area).This study aimed to isolate,identify,and characterize the biocontrol and growth promotion capacity of PGPR strains belonging to the Bacillus and Pseudomonas genera.The strains were tested against Sclerotinia minor,Sclerotium rolfsii,Fusarium verticillioides,and Aspergillus flavus for biocontrol assays.For growth promotion,pot trials used two peanut cultivars,ASEM 400 INTA and Granoleico,under 40%and 60%field capacity under two water regimes.The isolated strains were Bacillus velezensis,B.subtilis,B.tequilensis,B.safensis,B.altitudinis,and Pseudomonas psychrophila.These strains demonstrated in-vitro phosphorus solubilization,nitrogen fixation,ammonification,nitrification,enzyme releasing,phytohormones production,and high biocontrol capacity of over 75%.SC6 and RI3(both B.velezensis)and P10(P.psychrophila)exhibited outstanding performance.They significantly promoted peanut root biomass by more than 50%and leaf area by 30%,with increased chlorophyll content index and leaf relative water content,particularly under water stress conditions(40%field capacity).According to the results,RI3,SC6,and P10 could be classified as PGPR,which supports the results obtained in other field studies with these same microorganisms.Future investigations should prioritize the development of industrial formulations to assess their effectiveness in alternative crops and to incorporate them into other agricultural practices.展开更多
Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale ...Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale is limited.With evidence of consistent and substantial impact of harvest on soil microbial functional profiles across the region(despite a range of environmental conditions),the objective of this study was to determine the extent to which harvest also influences the structure of prokaryotic and fungal soil microbial communities,and how generalized these trends are throughout the geographic region.Paired soil samples were collected one year before and after harvest across nine second-growth Douglas-fir forests in the Pacific Northwest.Total community DNA was extracted from the soils,and high-throughput targeted gene sequencing of the 16 S r RNA gene for prokaryotes and the internal transcribed spacer(ITS)gene for fungi was performed.Alpha diversity was consistently and significantly higher after harvest;it was moderately so for fungal communities(+14.6%),but only marginally so for prokaryotic communities(+2.0%).Similarly,on average,a greater proportion of the variation in the community structure of fungi(20.1%)at each site was associated with forest harvest compared to that of prokaryotes(13.2%).Overall,the greatest influence of timber harvest on soil microbial communities appeared to be a relative depletion of ectomycorrhizal fungi,with a concomitant enrichment of saprotrophic fungi.Understanding the short-term responses of soil microbial communities across the region,particularly those of tree root-associated symbionts,may aid our understanding of the role soil microbial communities play in ecological succession.展开更多
Approaches for the cultivation-independent analysis of microbial communities are summarized as meta’omics,which predominantly includes metagenomic,-transcriptomic,-proteomic and-metabolomic studies.These have shown t...Approaches for the cultivation-independent analysis of microbial communities are summarized as meta’omics,which predominantly includes metagenomic,-transcriptomic,-proteomic and-metabolomic studies.These have shown that endophytic,root-associated and soil fungal communities are strongly shaped by associated plant species.The impact of plant identity on the composition of its litterssociated fungal community remains to be disentangled from the impact of litter chemistry.The composition of the plant community also shapes the fungal community.Most strikingly,adjacent plant species may share mycorrhizal symbionts even if the plants usually have different types of mycorrhizal fungi associated with them(ectomycorrhizal,ericoid and arbuscular mycorrhizal fungi).Environmental parameters weakly explain fungal community composition globally,and their effect is inconsistent at local and regional scales.Decrease in similarity among communities with increasing distance(i.e.distance decay)has been reported from local to global scales.This pattern is only exceptionally caused by spatial dispersal limitation of fungal propagules,but mostly due to the inability of the fungi to establish at the particular locality(i.e.environmental filtering or competitive exclusion).Fungal communities usually undergo pronounced seasonal changes and also differ between consecutive years.This indicates that development of the communities is usually not solely cyclic.Meta’omic studies challenge the classical view of plant litter decomposition.They show that mycorrhizal and(previously)endophytic fungi may be involved in plant litter decomposition and only partly support the idea of a succession from an Ascomycota to a Basidiomycota-dominated community.Furthermore,vertical separation of saprotrophic and mycorrhizal species in soil and sequential degradation from easily accessible to‘recalcitrant’plant compounds,such as lignin,can probably not be generalized.The current models of litter decomposition may therefore have to be eventually refined for certain ecosystems and environmental conditions.To gain deeper insights into fungal ecology,a meta’omic study design is outlined which focuses on environmental processes,because fungal communities are usually taxonomically diverse,but functionally redundant.This approach would initially identify dynamics of chemical shifts in the host and/or substrate by metametabolomics.Detected shifts would be subsequently linked to microbial activity by correlation with metatranscriptomic and/or metaproteomic data.A holistic trait-based approach might finally identify factors shaping taxonomic composition in communities against the dynamics of the environmental process(es)they are involved in.展开更多
基金supported by the National Key Research and Development Program of China(2023YFF0805602)the National Natural Science Foundation of China(U21A20186,32171579,32371592 and 32471674)the Natural Science Foundation of Gansu Province,China(23JRRA1029 and 23JRRA1034)。
文摘Plant roots interact with diverse fungi that are essential for maintaining the productivity and sustainability of pasture ecosystems,but how these root-associated fungi(RAF)differ between forage species and how they respond to nutrient enrichment and fungicide application are not well understood.Here,we constructed an 11-year experiment involving fungicide application(with or without)nested within four levels of experimental nitrogen(N)addition treatments in an alpine pasture,and the RAF communities,root traits,tissue nutrients,and shoot biomass of two dominant forage species(Carex capillifolia and Elymus nutans)were analyzed.The RAF community composition showed striking differences between the plant species and was strongly affected by both N addition level and fungicide applications.Fungicide,but not N application,dramatically reduced the RAF richness of all functional guilds in both plant species,and fungicide also simplified the co-occurrence network of the RAF for C.capillifolia.The RAF community correlated strongly with root traits,whereas their relationships became weakened or even vanished at the level of the individual plant species.The importance of RAF to plant nutrients and productivity varied between plant species,with significant contributions in C.capillifolia but not in E.nutans.This is the first report elucidating the long-term effect of fungicides on RAF in alpine pastures,and our findings emphasize the host-specific responses of RAF community structure and function to anthropogenic disturbances.
基金the National Natural Science Foundation of China(42107339)the China Agriculture Research System(CARS-04)。
文摘Wheat-maize(WM)and wheat-soybean(WS)double-cropping rotation systems are predominant in the North China Plain,with implications for national agricultural output and sustainability.As rotation systems exert legacy effects on soil health and crop productivity,the role of crop rotation in shaping the root-associated microbiome of the succeeding crops has emerged as a pivotal aspect of crop management research.Here,the effects of the preceding two cycles of WM and WS rotations on the recruitment and filtering of wheat root-associated bacterial communities across wheat developmental stages were investigated.Our results revealed that bacterial community diversity and composition were primarily influenced by compartment and developmental stage,while the preceding rotation systems had a slight but significant effect on wheat root-associated bacterial communities.The co-occurrence networks under WM were more complex in the wheat rhizosphere and rhizoplane,with the operational taxonomic units(OTUs)related to cellulolysis showing greater connectivity.The co-occurrence networks under WS were simple but stable in the rhizosphere and complex in the rhizoplane and endosphere,with the OTUs related to ureolysis and nitrogen fixation showing greater connectivity.While both stochastic and deterministic processes contributed to the assembly of wheat root-associated bacterial communities,the contributions of deterministic processes under WS were 19.4-38.5%higher than those under the WM rotation across the root-associated compartments,indicating the substantial impact of a soybean legacy effect on wheat root selection of microbes.Plant growthpromoting rhizobacteria with the potential to fix nitrogen,produce indole-3-acetic acid,and inhibit diseases such as Betaproteobacteriales,Azospirillales and Dyella sp.,were identified within the OTUs that were consistently enriched across all the wheat root-associated compartments and developmental stages,which were also important predictors of wheat yield.This study elucidates the role of crop rotation in modulating the dynamics of crop root-associated bacterial communities,and underscores the potential of targeted microbiome manipulation for optimizing wheat production and enhancing soil health.
基金jointly funded by the National Key Research and Development Program of China (No.2021YFD2200405)the National Natural Science Foundation of China (No.31930078)。
文摘Root-associated microbes play an essentialrole in mediating plant growth,health,and habitat adaptability.However,it is unknown which microbial taxa help develop host fitness and how habitats shape root-associated microbial assembly patterns.As an endemic species of subalpine forests in western Sichuan,China,Minjiang fir(Abies fargesii var.faxoniana)is dominant on cold-shaded northwestern slopes while absent on warm sunlit southwestern slopes.In this study,fungal and bacterial communities were investigated in three spatial compartments(endosphere,rhizosphere,and bulk soil)associated with Minjiang fir saplings on a cold-shaded northwestern slope and a warm sunlit southwestern slope.Habitats differentiated the microbial communities regardless of the spatial compartment and microbial taxa.Slope aspect variations caused shifts in root-associated(rhizosphere and endosphere)microbial compositions.Compared with the southwestern slope,the cold-shaded northwestern slope harbored a higher abundance of the growth-promoting bacteria Burkholderia and ectomycorrhizal fungi Cortinarius and Piloderma.The slope aspect had stronger effects on fungal diversity than bacterial diversity,with higher fungal endemism and lower bacterial endemism.Slope aspect variations were the dominant drivers of root-associated microbial communities,with lower contribution by soil properties and higher contribution by plant traits on the northwestern slope.Findings from this study could improve the understanding of plant habitat adaptability from the perspective of microbial community assembly.It is suggested that forest management should consider root-associated microbiomes for enhancing species fitness and habitat adaptability.
基金supported by the by National Natural Science Foundation of China(No.31830083)China National Key Program for Research and Development(No.2016YFD0100700)。
文摘Root-associated microbes are critical for plant growth and nutrient acquisition. However, scant information exists on optimizing communities of beneficial root-associated microbes or the mechanisms underlying their interactions with host plants. In this report, we demonstrate that rootassociated microbes are critical influencers of host plant growth and nutrient acquisition. Three synthetic communities(SynComs) were constructed based on functional screening of 1,893 microbial strains isolated from root-associated compartments of soybean plants. Functional assemblage of SynComs promoted significant plant growth and nutrient acquisition under both N/P nutrient deficiency and sufficiency conditions.Field trials further revealed that application of SynComs stably and significantly promoted plant growth, facilitated N and P acquisition, and subsequently increased soybean yield. Among the tested communities, SynCom1 exhibited the greatest promotion effect, with yield increases of up to 36.1% observed in two field sites. Further RNA-seq implied that SynCom application systemically regulates N and P signaling networks at the transcriptional level, which leads to increased representation of important growth pathways, especially those related to auxin responses. Overall,this study details a promising strategy for constructing SynComs based on functional screening,which are capable of enhancing nutrient acquisition and crop yield through the activities of beneficial root-associated microbes.
基金supported by the Sina-Australia Science Cooperation Fund(2010DFA31080)the National Natural Science Foundation(31172024)+1 种基金the Ministry of Science and Technology of China(20080242 and 2011ZX08004–001-03)the Zhejiang Bureau of Science and Technology (R3090229)
文摘Phosphorus （P） deficiency is a major limitation for plant growth and development. Among the wide set of responses to cope with low soil P, plants increase their level of intracellular and secreted acid phosphatases （APases）, which helps to catalyze inorganic phosphate （Pi） hydrolysis from organophosphates, in this study we characterized the rice （Oryza sativa） purple acid phosphatase 10a （OsPAPIOa）. OsPAPIOa belongs to group la of purple acid phosphatases （PAPs）, and clusters with the principal secreted PAPs in a variety of plant species including Arabidopsis. The transcript abundance of OsPAPIOa is specifically induced by Pi deficiency and is controlled by OsPHR2, the central transcription factor controlling Pi homeostasis. In gel activity assays of root and shoot protein extracts, it was revealed that OsPAPIOa is a major acid phosphatase isoform induced by Pi starvation. Constitutive overexpression of OsPAPIOa results in a significant increase of phosphatase activity in both shoot and root protein extracts. In vivo root 5-bromo.4-chloro-3-indolyl-phosphate （BCIP） assays and activity measurements on external media showed that OsPAPIOa is a root-associated APase. Furthermore, overexpression of OsPAPIOa significantly improved ATP hydrolysis and utilization compared with wild type plants. These results indicate that OsPAPIOa can potentially be used for crop breeding to improve the efficiency of P use.
基金the National Natural Science Foundation of China(41721001,41771269)China Agriculture Research System(CARS-04)the National Key Research and Development Program of China(2016YFD0800207).
文摘Soil-derived microbiota associated with plant roots are conducive to plant growth and stress resistance.However,the spatio-temporal dynamics of microbiota in response to organochlorine pollution during the unstable vegetative growth phase of rice is not well understood.In this study,we focused on the rice(Oryza sativa L.)microbiota across the bulk soil,rhizosphere and endosphere compartments during the vegetative growth phase in two different soils with and without lindane pollutant.The results showed that the factors of growth time,soil types and rhizo-compartments had significant influence on the microbial communities of rice,while lindane mostly stimulated the construction of endosphere microbiota at the vegetative phase.Active rice root-soil-microbe interactions induced an inhibition effect on lindane removal at the later vegetative growth phase in rice-growth-dependent anaerobic condition,likely due to the root oxygen loss and microbial mediated co-occurring competitive electron-consuming redox processes in soils.Each rhizocompartment owned distinct microbial communities,and therefore,presented specific ecologically functional categories,while the moderate functional differences were also affected by plants species and residual pollution stress.This work revealed the underground micro-ecological process of microbiota and especially their potential linkage to the natural attenuation of residual organochlorine such as lindane.
基金the Universidad Nacional de Co rdoba,Argentina,and the Secretaría de Cienciay Tecnología (UNC,SECyT) for the financial support of the CONSOLIDAR 2018–2022 project‘EFECTO DE LOS MICROORGANISMOS PROMOTORES DEL CRECIMIENTO SOBRE LA ECOFISIOLOGíA Y EL CONTROL DE ENFERMEDADES EN EL CULTIVO DE MANí.'the Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) for the doctoral fellowshipthe University of Córdoba (Spain) for the support provided through the “Plan Propio de Investigación” 2020–2024。
文摘To improve crop yields,global food production needs sustainable agronomic tools like Plant Growth-Promoting Rhizobacteria(PGPR).Region-adapted PGPR strains are crucial to increasing peanut production.Argentina is the seventh-largest peanut producer,and Cordoba is the main region with 250,000 ha(75%of the total sowing area).This study aimed to isolate,identify,and characterize the biocontrol and growth promotion capacity of PGPR strains belonging to the Bacillus and Pseudomonas genera.The strains were tested against Sclerotinia minor,Sclerotium rolfsii,Fusarium verticillioides,and Aspergillus flavus for biocontrol assays.For growth promotion,pot trials used two peanut cultivars,ASEM 400 INTA and Granoleico,under 40%and 60%field capacity under two water regimes.The isolated strains were Bacillus velezensis,B.subtilis,B.tequilensis,B.safensis,B.altitudinis,and Pseudomonas psychrophila.These strains demonstrated in-vitro phosphorus solubilization,nitrogen fixation,ammonification,nitrification,enzyme releasing,phytohormones production,and high biocontrol capacity of over 75%.SC6 and RI3(both B.velezensis)and P10(P.psychrophila)exhibited outstanding performance.They significantly promoted peanut root biomass by more than 50%and leaf area by 30%,with increased chlorophyll content index and leaf relative water content,particularly under water stress conditions(40%field capacity).According to the results,RI3,SC6,and P10 could be classified as PGPR,which supports the results obtained in other field studies with these same microorganisms.Future investigations should prioritize the development of industrial formulations to assess their effectiveness in alternative crops and to incorporate them into other agricultural practices.
基金supported by Weyerhaeuser Natural Resource Company.
文摘Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale is limited.With evidence of consistent and substantial impact of harvest on soil microbial functional profiles across the region(despite a range of environmental conditions),the objective of this study was to determine the extent to which harvest also influences the structure of prokaryotic and fungal soil microbial communities,and how generalized these trends are throughout the geographic region.Paired soil samples were collected one year before and after harvest across nine second-growth Douglas-fir forests in the Pacific Northwest.Total community DNA was extracted from the soils,and high-throughput targeted gene sequencing of the 16 S r RNA gene for prokaryotes and the internal transcribed spacer(ITS)gene for fungi was performed.Alpha diversity was consistently and significantly higher after harvest;it was moderately so for fungal communities(+14.6%),but only marginally so for prokaryotic communities(+2.0%).Similarly,on average,a greater proportion of the variation in the community structure of fungi(20.1%)at each site was associated with forest harvest compared to that of prokaryotes(13.2%).Overall,the greatest influence of timber harvest on soil microbial communities appeared to be a relative depletion of ectomycorrhizal fungi,with a concomitant enrichment of saprotrophic fungi.Understanding the short-term responses of soil microbial communities across the region,particularly those of tree root-associated symbionts,may aid our understanding of the role soil microbial communities play in ecological succession.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,project PE 1673/4-1).
文摘Approaches for the cultivation-independent analysis of microbial communities are summarized as meta’omics,which predominantly includes metagenomic,-transcriptomic,-proteomic and-metabolomic studies.These have shown that endophytic,root-associated and soil fungal communities are strongly shaped by associated plant species.The impact of plant identity on the composition of its litterssociated fungal community remains to be disentangled from the impact of litter chemistry.The composition of the plant community also shapes the fungal community.Most strikingly,adjacent plant species may share mycorrhizal symbionts even if the plants usually have different types of mycorrhizal fungi associated with them(ectomycorrhizal,ericoid and arbuscular mycorrhizal fungi).Environmental parameters weakly explain fungal community composition globally,and their effect is inconsistent at local and regional scales.Decrease in similarity among communities with increasing distance(i.e.distance decay)has been reported from local to global scales.This pattern is only exceptionally caused by spatial dispersal limitation of fungal propagules,but mostly due to the inability of the fungi to establish at the particular locality(i.e.environmental filtering or competitive exclusion).Fungal communities usually undergo pronounced seasonal changes and also differ between consecutive years.This indicates that development of the communities is usually not solely cyclic.Meta’omic studies challenge the classical view of plant litter decomposition.They show that mycorrhizal and(previously)endophytic fungi may be involved in plant litter decomposition and only partly support the idea of a succession from an Ascomycota to a Basidiomycota-dominated community.Furthermore,vertical separation of saprotrophic and mycorrhizal species in soil and sequential degradation from easily accessible to‘recalcitrant’plant compounds,such as lignin,can probably not be generalized.The current models of litter decomposition may therefore have to be eventually refined for certain ecosystems and environmental conditions.To gain deeper insights into fungal ecology,a meta’omic study design is outlined which focuses on environmental processes,because fungal communities are usually taxonomically diverse,but functionally redundant.This approach would initially identify dynamics of chemical shifts in the host and/or substrate by metametabolomics.Detected shifts would be subsequently linked to microbial activity by correlation with metatranscriptomic and/or metaproteomic data.A holistic trait-based approach might finally identify factors shaping taxonomic composition in communities against the dynamics of the environmental process(es)they are involved in.
