Cucumber (Cucumis sativus) is one of the most widely used vegetable in the world,and different pesticides have been extensively used for controlling the insects and disease pathogens of this plant.However,little is kn...Cucumber (Cucumis sativus) is one of the most widely used vegetable in the world,and different pesticides have been extensively used for controlling the insects and disease pathogens of this plant.However,little is known about how the pesticides affect the microbial community in cucumber phyllosphere.This study was the first attempt to assess the impact of pyrethroid insecticide cyperemethrin on the microbial communities of cucumber phyllosphere using biochemical and genetic approaches.Phospholipid fatty ac...展开更多
Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere....Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.展开更多
The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high lev...The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate (filtrate to fungal spores inocula mixed in proportion 1 : 50). These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.展开更多
Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity ...Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity is limited.The aim of this study is to identify the environmental factors that drive phyllosphere algal community composition and diversity in rainforests.For this purpose,we used single molecule real-time sequencing of full-length 18S rDNA to characterize the composition of phyllosphere microalgal communities growing on four host tree species(Ficus tikoua,Caryota mitis,Arenga pinnata,and Musa acuminata) common to three types of forest over four months at the Xishuangbanna Tropical Botanical Garden,Yunnan Province,China.Environmental 18S rDNA sequences revealed that the green algae orders Watanabeales and Trentepohliales were dominant in almost all algal communities and that phyllosphere algal species richness and biomass were lower in planted forest than in primeval and reserve rainforest.In addition,algal community composition differed significantly between planted forest and primeval rainforest.We also found that algal communities were affected by soluble reactive phosphorous,total nitrogen,and ammonium contents.Our findings indicate that algal community structure is significantly related to forest type and host tree species.Furthermore,this study is the first to identify environmental factors that affect phyllosphere algal communities,significantly contributing to future taxonomic research,especially for the green algae orders Watanabeales and Trentepohliales.This research also serves as an important reference for molecular diversity analysis of algae in other specific habitats,such as epiphytic algae and soil algae.展开更多
Neighborhood gardens serve as sensitive sites for human microbial encounters,with phyllosphere microbes directly impacting our respiratory health.Yet,our understanding remains limited on how factors like season,garden...Neighborhood gardens serve as sensitive sites for human microbial encounters,with phyllosphere microbes directly impacting our respiratory health.Yet,our understanding remains limited on how factors like season,garden age,and land use shape the risk of respiratory diseases(RDs)tied to these garden microbes.Here we examined the microbial communities within the phyllosphere of 72 neighborhood gardens across Shanghai,spanning different seasons(warm and cold),garden ages(old and young),and locales(urban and rural).We found a reduced microbial diversity during the cold season,except for Gammaproteobacteria which exhibited an inverse trend.While land use influenced the microbial composition,urban and rural gardens had strikingly similar microbial profiles.Alarmingly,young gardens in the cold season hosted a substantial proportion of RDs-associated species,pointing towards increased respiratory inflammation risks.In essence,while newer gardens during colder periods show a decline in microbial diversity,they have an increased presence of RDs-associated microbes,potentially escalating respiratory disease prevalence.This underscores the pivotal role the garden age plays in enhancing both urban microbial diversity and respiratory health.展开更多
Planktonic microorganisms have been recognized as important components in biogeochemical cycling in lakes.However,research into the impact of phyllosphere microorganisms,particularly those involved in carbon cycling,o...Planktonic microorganisms have been recognized as important components in biogeochemical cycling in lakes.However,research into the impact of phyllosphere microorganisms,particularly those involved in carbon cycling,on CO_(2) fluxes in macrophyte-dominated lakes within the context of global environmental changes remains scarce.Here,by employing high-throughput sequencing techniques,we experimentally tested how nutrient enrichment,top-down effects of fish and increases in dissolved organic carbon(DOC)affect CO_(2) exchange flux at the water-air interface by altering the community structure and functioning of phyllosphere bacteria on macrophytes.We found that our mesocosm ecosystems exhibited a net absorption of CO_(2),but nutrient enrichment significantly decreased the absorption ability.Mantel tests and multiple regression modeling also showed that eutrophication-associated parameters(total nitrogen,total phosphorus and ammonium nitrogen),pH,and extinction coefficient were the key drivers influencing abundance of phyllosphere functional microorganisms.In addition,these experimental treatments significantly altered the composition,diversity and co-occurrence networks of carbon cyclingassociated phyllosphere microorganisms,which impacted the CO_(2) flux.Structural equation models and linear regression further showed that the Shannon Index of phyllosphere functional microorganisms related to carbon cycling(rather than plant volume inhabited-PVI)had a significant positive impact on CO_(2) fixation.This means that environmental changes—especially eutrophication—may hinder carbon sequestration by decreasing the diversity of phyllosphere microorganisms rather than reducing the abundance of submerged macrophytes.This study increases our understanding of carbon cycling processes in aquatic environments from a management perspective by emphasizing the importance of protecting the diversity of phyllosphere microorganisms in macrophyte-dominated lakes.展开更多
Background:Plant phyllosphere microbes are important for the host plant's protection.Plant growth-promoting rhizobacteria(PGPR)and Trichoderma are common biocontrol agents(BCAs)for disease management.Pathogens and...Background:Plant phyllosphere microbes are important for the host plant's protection.Plant growth-promoting rhizobacteria(PGPR)and Trichoderma are common biocontrol agents(BCAs)for disease management.Pathogens and BCAs can change the rhizosphere microbial composition;however,the effect of PGPR or Trichoderma on plant phyllosphere microbes,particularly for mesocosms involving the interaction between pathogens and BCAs,is not well known.Methods:High-throughput sequencing was used to identify the phyllosphere bacterial community of common vetch interacting with Colletotrichum spinaciae,two PGPRs(Bacillus subtilis and Bacillus licheniformis),and Trichoderma longibrachiatum.We evaluated anthracnose severity,phyllosphere bacteria diversity and composition,and the relationship between the activities of plant defense enzymes and hormonal molecules in plants treated with individual and combined inoculations of PGPRs,Trichoderma,and C.spinaciae.Results:PGPR or Trichoderma alone reduced disease severity.Trichoderma reduced the salicylic acid content,PGPR increased the catalase activity in plants,and co-inoculation of PGPR and Trichoderma decreased the salicylic acid content.Inoculation of PGPR and Trichoderma individually or in combination changed the disease-associated phyllosphere bacteria,and this effect was related to plant defense enzymes and hormonal molecules.Conclusions:We suggest that the plant defense response induced by PGPR and Trichoderma results in the enrichment of a fraction of favorable chloroplastic bacteria,which facilitates plant defense against diseases.展开更多
Plants are colonized by various microorganisms in natural environments.While many studies have demonstrated key roles of the rhizosphere microbiota in regulating biological processes such as nutrient acquisition and r...Plants are colonized by various microorganisms in natural environments.While many studies have demonstrated key roles of the rhizosphere microbiota in regulating biological processes such as nutrient acquisition and resistance against abiotic and biotic challenges,less is known about the role of the phyllosphere microbiota and how it is established and maintained.This review provides an update on current understanding of phyllosphere community assembly and the mechanisms by which plants and microbes establish the phyllosphere microbiota for plant health.展开更多
Phyllosphere is an important reservoir of antibiotic resistance genes(ARGs),but the transfer mechanism of ARGs from soil and air to phyllosphere remains unclear.This study demonstrated that soil-air-phyllosphere was t...Phyllosphere is an important reservoir of antibiotic resistance genes(ARGs),but the transfer mechanism of ARGs from soil and air to phyllosphere remains unclear.This study demonstrated that soil-air-phyllosphere was the dominant ARG transfer pathway,and blocking it by film mulching can reduce typical phyllosphere ARGs in lettuce by 80.7%-98.7%(89.5%on average).To further eliminate phyllosphere ARGs in lettuce grown with film mulching,the internal soil-endosphere-phyllosphere transfer pathway deserves more attention.We analyzed the ARG hosts and the resistome in lettuce rhizosphere and phyllosphere with film mulching via hybrid Illumina-Nanopore sequencing.Pseudomonas sp.7SR1 was more abundant than other ARG hosts,accounting for 1.0%and 47.1%of the total bacteria in rhizosphere and phyllosphere,respectively.The species has flagella that can promote mobility and can excrete extracellular polymeric substances and/or surfactant-like microbial products,which benefits its colonization in the phyllosphere.Impeding the migration of Pseudomonas sp.7SR1 via the soil-endosphere-phyllosphere pathway would be effective to further reduce ARGs in phyllosphere.Multidrug resistant genes were predominant in phyllosphere(40.3%of the total),and 87.6%of the phyllosphere ARGs were located on chromosomes,indicating relatively low horizontal gene transfer(HGT)potentials.This study provides insights into the transfer mechanism,hosts,and control strategies of phyllosphere ARGs in typical plants.展开更多
A bacterium capable of degrading dichlorvos was isolated from the rape phyllosphere and designated YD4. The strain was identified as Flavobacterium sp., based on its phenotypic features and 16S rRNA gene sequence. Str...A bacterium capable of degrading dichlorvos was isolated from the rape phyllosphere and designated YD4. The strain was identified as Flavobacterium sp., based on its phenotypic features and 16S rRNA gene sequence. Strain YD4 was able to utilize dichlorvos as the sole source of phosphorus. In situ enhanced bioremedia- tion of dichlorvos by YD4 was hereafter studied. Chlorpyrifos and phoxim could also be degraded by this strain as the sole phosphorus source. A higher degradation rate of dichlorvos was observed after spraying YD4 onto the surface of rape leaves when compared to the sterilized- YD4 and water-treated samples. The results indicated that pesticide-degrading epiphytic bacterium could become a new way for in situ phyllosphere bioremediation where the hostile niche is unsuitable for other pesticide-degrading bacteria isolated from soil and water.展开更多
Chemical exposure can indirectly affect leaf microbiota communities,but the mechanism driving this phenomenon remains largely unknown.Results revealed that the co-exposure of glyphosate and multi-carbon nanotubes(CNTs...Chemical exposure can indirectly affect leaf microbiota communities,but the mechanism driving this phenomenon remains largely unknown.Results revealed that the co-exposure of glyphosate and multi-carbon nanotubes(CNTs)caused a synergistic inhibitory effect on the growth and metabolism of Arabidopsis thaliana shoots.However,only a slight inhibitory effect was induced by nanotubes or glyphosate alone at the tested concentrations.Several intermediate metabolites of nitrogen metabolism and fatty acid synthesis pathways were upregulated under the combined treatment,which increased the amount of energy required to alleviate the disruption caused by the combined treatment.Additionally,compared with the two individual treatments,the glyphosate/nanotube combination treatment induced greater fluctuations in the phyllosphere bacterial community members with low abundance(relative abundance(RA)<1%)at both the family and genus levels,and among these bacteria some plant growth promotion and nutrient supplement related bacteria were markable increased.Strikingly,strong correlations between phyllosphere bacterial diversity and metabolites suggested a potential role of leaf metabolism,particularly nitrogen and carbohydrate metabolism,in restricting the range of leaf microbial taxa.These correlations between phyllosphere bacterial diversity and leaf metabolism will improve our understanding of plant-microbe interactions and the extent of their drivers of variation and the underlying causes of variability in bacterial community composition.展开更多
Bacterial populations coexisting in the phyllosphere niche have important effects on plant health. Quorum sensing (QS) allows bacteria to communicate via diffusible signal molecules, but QS-dependent behaviors in ph...Bacterial populations coexisting in the phyllosphere niche have important effects on plant health. Quorum sensing (QS) allows bacteria to communicate via diffusible signal molecules, but QS-dependent behaviors in phyllosphere bacterial populations are poorly understood. We investigate the dense and diverse N-acyl-homoserine lactone (AHL)-producing phyllosphere bacteria living on tobacco leaf surfaces via a culture-dependent method and 16S rRNA gene sequencing. Our results indicated that approximately 7.9%-11.7% of the culturable leaf-associated bacteria have the ability to produce AHL based on the assays using whole-cell biosensors. Sequencing of the 16S rRNA gene assigned the AHL-producing strains to two phylogenetic groups, with Gammaproteobacteria (93%) as the predominant group, followed by Alphaproteobacteria. All of the AHL-producing Alphaproteobacteria were affiliated with the genus Rhizobium, whereas the AHL-producing bacteria belonging to the Gammaproteobacteria mainly fell within the genera Pseudomonas, Acinetobacter, Citrobacter, Enterobacter, Pantoea and Serratia. The bioassays of supernatant extracts revealed that a portion of the strains have a remarkable AHL profile for AHL induction activity using the two different biosensors, and one compound in the active extract of a representative isolate, NTL223, corresponded to 3-oxo-hexanoyl-homoserine lactone. A large population size and diversity of bacteria capable of AHL-driven QS were found to cohabit on leaves, implying that cross-communication based AHL-type QS may be common in the phyllosphere. Furthermore, this study provides a general snapshot of a potential valuable application of AHL-producing bacteria inhabiting leaves for their presumable ecological roles in the phyllosphere.展开更多
Imazethapyr(IM)is a widely used acetolactate synthase-inhibiting chiral herbicide.It has long-term residuals that may be absorbed by the human body through the edible parts of plants,such as vegetable leaves or fruits...Imazethapyr(IM)is a widely used acetolactate synthase-inhibiting chiral herbicide.It has long-term residuals that may be absorbed by the human body through the edible parts of plants,such as vegetable leaves or fruits.Here,we selected a model plant,Arabidopsis thaliana,to determine the effects of R-IM and S-IM on its leaf structure,photosynthetic efficiency,and metabolites,as well as the structures of microorganisms in the phyllosphere,after 7 days of exposure.Our results indicated enantiomeric differences in plant growth between R-IM and S-IM;133μg/kg R-IM showed heavier inhibition of photosynthetic efficiency and greater changes to subcellular structure than S-IM.R-IM and S-IM also had different effects on metabolism and leaf microorganisms.S-IM mainly increased lipid compounds and decreased amino acids,while R-IM increased sugar accumulation.The relative abundance of Moraxellaceae human pathogenic bacteria was increased by R-IM treatment,indicating that R-IM treatment may increase leaf surface pathogenic bacteria.Our research provides a new perspective for evaluating the harmfulness of pesticide residues in soil,phyllosphere microbiome changes via the regulation of plant metabolism,and induced pathogenic bacterial accumulation risks.展开更多
Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host...Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous.Utilizing high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest China.Functional annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities.Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal community.Comparison across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant characteristics.FAPROTAX prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form plants.FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa.Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly.Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted both bacterial and fungal community composition,with fungal community composition showing a closer association with leaf nutrients and physiology compared with bacterial community composition.The distinct responses of bacterial and fungal communities to plant traits were attributed to the differing properties of bacteria and fungi,such as bacteria having higher potential dispersal rates and broader ecological niches than fungi.Overall,the results indicate that phyllosphere bacterial and fungal communities undergo similar community assembly processes,with fungi being more influenced by plant characteristics than bacteria.These findings offer novel insights into the ecology of phyllosphere microbial communities of desert plants.展开更多
Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species. However, the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood. We inv...Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species. However, the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood. We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes: Vallisneria natans and Hydrilla verticillata in Taihu Lake, Jiangsu, China, using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes. The results show that: (1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria, and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria, including Burkholderiales, was the most abundant bacterial group on both plants. Cyanobacteria and Gammaproteobacteria were the second largest groups on V. natans and H. verticillata, respectively. Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations. Both ANOSIM of the T-RFLP data and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants. Therefore, the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific, which may aid in understanding the ecological functions of submerged macrophytes in general.展开更多
Endophytic fungal isolates(139 no.)were obtained from 143(62 roots,18 fruits and 54 leaves)samples of 15 different varieties of banana collected from 10 sites in Assam,India during 2018-2019.Overall isolation fr...Endophytic fungal isolates(139 no.)were obtained from 143(62 roots,18 fruits and 54 leaves)samples of 15 different varieties of banana collected from 10 sites in Assam,India during 2018-2019.Overall isolation frequency from surface-sterilized tissue ranged from 10%-80%(as per site)and 6%-70%(as per variety of banana).All isolates were segregated into 40 different types on the basis of macromorphological and micro morphological characteristics.Forty different fungal taxa were isolated belonging to 14 genera including Absidia,Arthrinium,Aspergillus,Bipolaris,Cladosporium,Curvularia,Dendrophion,Fusarium,Humicola,Mortierella,Mucor,Penicillium,Paecilomyces,Verticillium and one mycelium sterile.Among them,Cladosporium cladosporioidies and Paecilomyces sp.frequently occurred in most of the sites surveyed whereas Cladospoirum cladosporioides and Aspergillus sp.8,Fusarium graminseram were most frequently isolated from different varieties.However,all sites differed in their fungal diversity.Banana samples from Narigoan and Jorhat have been found with maximum fungal species followed by marigoan samples so as to Banana varieties Amrit Sagar endowed 27 no.of fungi followed by Jehaji and Honda which were associated with a maximum 14 fungal sp.Isolation frequency and relative abundance of Cladosporium cladosporiodes(80%,4.6),Paecilomyces farinosus(80%,4.6)followed by Penicillium ruburm,Aspergillus sp.8&9(70%,4.02)were recorded as maximum comparatively in different sites.However,Aspergillus sp.8,Mortieralla sp.and Pacilomyces farinosus are isolated frequently from different banana varieties(73.33%,4.93).展开更多
Soil salinity is a worldwide problem threatening crop yields.Some plant growth-promoting rhizobacteria(PGPR)could survive in high salt environment and assist plant adaptation to stress.Nevertheless,the genomic and met...Soil salinity is a worldwide problem threatening crop yields.Some plant growth-promoting rhizobacteria(PGPR)could survive in high salt environment and assist plant adaptation to stress.Nevertheless,the genomic and metabolic features,as well as the regulatory mechanisms promoting salt tolerance in plants by these bacteria remain largely unknown.In the current work,a novel halotolerant PGPR strain,namely,Bacillus sp.strain RA can enhance tomato tolerance to salt stress.Comparative genomic analysis of strain RA with its closely related species indicated a high level of evolutionary plasticity exhibited by strain-specific genes and evolutionary constraints driven by purifying selection,which facilitated its genomic adaptation to salt-affected soils.The transcriptome further showed that strain RA could tolerate salt stress by balancing energy metabolism via the reprogramming of biosynthetic pathways.Plants exude a plethora of metabolites that can strongly influence plant fitness.The accumulation of myo-inositol in leaves under salt stress was observed,leading to the promotion of plant growth triggered by Bacillus sp.strain RA.Importantly,myo-inositol serves as a selective force in the assembly of the phyllosphere microbiome and the recruitment of plant-beneficial species.It promotes destabilizing properties in phyllosphere bacterial co-occurrence networks,but not in fungal networks.Furthermore,interdomain interactions between bacteria and fungi were strengthened by myo-inositol in response to salt stress.This work highlights the genetic adaptation of RA to salt-affected soils and its ability to impact phyllosphere microorganisms through the adjustment of myo-inositol metabolites,thereby imparting enduring resistance against salt stress in tomato.展开更多
A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investiga...A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater (MGW) and potato wastewater (PW) as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW (1:9).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
Imazethapyr (IM) is an acetolactate synthase (ALS)-inhibiting herbicide that has been widely used in recent years.However,IM spraying can lead to the accumulation of herbicide residues in leaves.Here,we determined the...Imazethapyr (IM) is an acetolactate synthase (ALS)-inhibiting herbicide that has been widely used in recent years.However,IM spraying can lead to the accumulation of herbicide residues in leaves.Here,we determined the effects of IM spraying on the plant growth and leaf surface microbial communities of Arabidopsis thaliana after 7 and 14 days of exposure.The results suggested that IM spraying inhibited plant growth.Fresh weight decreased to 48% and 26% of the control value after 7 and 14 days,respectively,of 0.035 kg/ha IM exposure.In addition,anthocyanin content increased 9.2-fold and 37.2-fold relative to the control content after 7 and 14 days of treatment,respectively.Furthermore,IM spraying destroyed the cell structures of the leaves,as evidenced by increases in the number of starch granules and the stomatal closure rate.Reductions in photosynthetic efficiency and antioxidant enzyme activity were observed after IM spraying,especially after 14 days of exposure.The diversity and evenness of the leaf microbiota were not affected by IM treatment,but the composition of community structure at the genus level was altered by IM spraying.Imazethapyr application increased the abundance of Pseudomonas,a genus that includes species pathogenic to plants and humans,indicating that IM potentially increased the abundance of pathogenic bacteria on leaves.Our findings increase our understanding of the relationships between herbicide application and the microbial community structures on plant leaves,and they provide a new perspective for studying the ecological safety of herbicide usage.展开更多
基金the National Natural Science Foundation of China (No.30600082)the Australian Research Council (ARC) International Linkage Fellowship (No.LX0560210).
文摘Cucumber (Cucumis sativus) is one of the most widely used vegetable in the world,and different pesticides have been extensively used for controlling the insects and disease pathogens of this plant.However,little is known about how the pesticides affect the microbial community in cucumber phyllosphere.This study was the first attempt to assess the impact of pyrethroid insecticide cyperemethrin on the microbial communities of cucumber phyllosphere using biochemical and genetic approaches.Phospholipid fatty ac...
基金supported by the National Natural Science Foundation of China (No.30600082,20777089)the "Knowledge Innovation" Program of Chinese Academy of Sciences (No.kzcx1-yw-06-03)the Key Technologies R&D Program of China (No.2008BADA7B01)
文摘Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.
基金State Tobacco Monopoly Administration of China (110200201008)
文摘The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate (filtrate to fungal spores inocula mixed in proportion 1 : 50). These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.
基金supported by the National Natural Science Foundation of China (Grant no.31870189 and 32000168)。
文摘Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity is limited.The aim of this study is to identify the environmental factors that drive phyllosphere algal community composition and diversity in rainforests.For this purpose,we used single molecule real-time sequencing of full-length 18S rDNA to characterize the composition of phyllosphere microalgal communities growing on four host tree species(Ficus tikoua,Caryota mitis,Arenga pinnata,and Musa acuminata) common to three types of forest over four months at the Xishuangbanna Tropical Botanical Garden,Yunnan Province,China.Environmental 18S rDNA sequences revealed that the green algae orders Watanabeales and Trentepohliales were dominant in almost all algal communities and that phyllosphere algal species richness and biomass were lower in planted forest than in primeval and reserve rainforest.In addition,algal community composition differed significantly between planted forest and primeval rainforest.We also found that algal communities were affected by soluble reactive phosphorous,total nitrogen,and ammonium contents.Our findings indicate that algal community structure is significantly related to forest type and host tree species.Furthermore,this study is the first to identify environmental factors that affect phyllosphere algal communities,significantly contributing to future taxonomic research,especially for the green algae orders Watanabeales and Trentepohliales.This research also serves as an important reference for molecular diversity analysis of algae in other specific habitats,such as epiphytic algae and soil algae.
基金supported by the Natural Science Foundation of China(Project number:32371843)the Science and Technology Commission of Shanghai Municipality(Project number:22230713300).
文摘Neighborhood gardens serve as sensitive sites for human microbial encounters,with phyllosphere microbes directly impacting our respiratory health.Yet,our understanding remains limited on how factors like season,garden age,and land use shape the risk of respiratory diseases(RDs)tied to these garden microbes.Here we examined the microbial communities within the phyllosphere of 72 neighborhood gardens across Shanghai,spanning different seasons(warm and cold),garden ages(old and young),and locales(urban and rural).We found a reduced microbial diversity during the cold season,except for Gammaproteobacteria which exhibited an inverse trend.While land use influenced the microbial composition,urban and rural gardens had strikingly similar microbial profiles.Alarmingly,young gardens in the cold season hosted a substantial proportion of RDs-associated species,pointing towards increased respiratory inflammation risks.In essence,while newer gardens during colder periods show a decline in microbial diversity,they have an increased presence of RDs-associated microbes,potentially escalating respiratory disease prevalence.This underscores the pivotal role the garden age plays in enhancing both urban microbial diversity and respiratory health.
基金financially supported by the National Natural Science Foundation of China(9225130432371644)Scientific Research and Innovation Project of Postgraduate Students in the Academic Degree of Yunnan University(KC-23233782).
文摘Planktonic microorganisms have been recognized as important components in biogeochemical cycling in lakes.However,research into the impact of phyllosphere microorganisms,particularly those involved in carbon cycling,on CO_(2) fluxes in macrophyte-dominated lakes within the context of global environmental changes remains scarce.Here,by employing high-throughput sequencing techniques,we experimentally tested how nutrient enrichment,top-down effects of fish and increases in dissolved organic carbon(DOC)affect CO_(2) exchange flux at the water-air interface by altering the community structure and functioning of phyllosphere bacteria on macrophytes.We found that our mesocosm ecosystems exhibited a net absorption of CO_(2),but nutrient enrichment significantly decreased the absorption ability.Mantel tests and multiple regression modeling also showed that eutrophication-associated parameters(total nitrogen,total phosphorus and ammonium nitrogen),pH,and extinction coefficient were the key drivers influencing abundance of phyllosphere functional microorganisms.In addition,these experimental treatments significantly altered the composition,diversity and co-occurrence networks of carbon cyclingassociated phyllosphere microorganisms,which impacted the CO_(2) flux.Structural equation models and linear regression further showed that the Shannon Index of phyllosphere functional microorganisms related to carbon cycling(rather than plant volume inhabited-PVI)had a significant positive impact on CO_(2) fixation.This means that environmental changes—especially eutrophication—may hinder carbon sequestration by decreasing the diversity of phyllosphere microorganisms rather than reducing the abundance of submerged macrophytes.This study increases our understanding of carbon cycling processes in aquatic environments from a management perspective by emphasizing the importance of protecting the diversity of phyllosphere microorganisms in macrophyte-dominated lakes.
基金China Modern Agriculture Research System,Grant/Award Number:CARS-22 Green Manure。
文摘Background:Plant phyllosphere microbes are important for the host plant's protection.Plant growth-promoting rhizobacteria(PGPR)and Trichoderma are common biocontrol agents(BCAs)for disease management.Pathogens and BCAs can change the rhizosphere microbial composition;however,the effect of PGPR or Trichoderma on plant phyllosphere microbes,particularly for mesocosms involving the interaction between pathogens and BCAs,is not well known.Methods:High-throughput sequencing was used to identify the phyllosphere bacterial community of common vetch interacting with Colletotrichum spinaciae,two PGPRs(Bacillus subtilis and Bacillus licheniformis),and Trichoderma longibrachiatum.We evaluated anthracnose severity,phyllosphere bacteria diversity and composition,and the relationship between the activities of plant defense enzymes and hormonal molecules in plants treated with individual and combined inoculations of PGPRs,Trichoderma,and C.spinaciae.Results:PGPR or Trichoderma alone reduced disease severity.Trichoderma reduced the salicylic acid content,PGPR increased the catalase activity in plants,and co-inoculation of PGPR and Trichoderma decreased the salicylic acid content.Inoculation of PGPR and Trichoderma individually or in combination changed the disease-associated phyllosphere bacteria,and this effect was related to plant defense enzymes and hormonal molecules.Conclusions:We suggest that the plant defense response induced by PGPR and Trichoderma results in the enrichment of a fraction of favorable chloroplastic bacteria,which facilitates plant defense against diseases.
基金This work was supported by the Chinese Academy of Sciences,Center for Excellence in Molecular Plant Sciences/Institute of Plant Physiology and Ecology,National Key Laboratory of Molecular Plant Genetics and the Chinese Academy of Sciences Strategic Priority Research Program(type B,project no.XDB27040211).
文摘Plants are colonized by various microorganisms in natural environments.While many studies have demonstrated key roles of the rhizosphere microbiota in regulating biological processes such as nutrient acquisition and resistance against abiotic and biotic challenges,less is known about the role of the phyllosphere microbiota and how it is established and maintained.This review provides an update on current understanding of phyllosphere community assembly and the mechanisms by which plants and microbes establish the phyllosphere microbiota for plant health.
基金supported by the National Natural Science Foundation of China(Nos.21836003 and 21621005)the National Key Research and Development Program of China(No.2020YFC1806903)。
文摘Phyllosphere is an important reservoir of antibiotic resistance genes(ARGs),but the transfer mechanism of ARGs from soil and air to phyllosphere remains unclear.This study demonstrated that soil-air-phyllosphere was the dominant ARG transfer pathway,and blocking it by film mulching can reduce typical phyllosphere ARGs in lettuce by 80.7%-98.7%(89.5%on average).To further eliminate phyllosphere ARGs in lettuce grown with film mulching,the internal soil-endosphere-phyllosphere transfer pathway deserves more attention.We analyzed the ARG hosts and the resistome in lettuce rhizosphere and phyllosphere with film mulching via hybrid Illumina-Nanopore sequencing.Pseudomonas sp.7SR1 was more abundant than other ARG hosts,accounting for 1.0%and 47.1%of the total bacteria in rhizosphere and phyllosphere,respectively.The species has flagella that can promote mobility and can excrete extracellular polymeric substances and/or surfactant-like microbial products,which benefits its colonization in the phyllosphere.Impeding the migration of Pseudomonas sp.7SR1 via the soil-endosphere-phyllosphere pathway would be effective to further reduce ARGs in phyllosphere.Multidrug resistant genes were predominant in phyllosphere(40.3%of the total),and 87.6%of the phyllosphere ARGs were located on chromosomes,indicating relatively low horizontal gene transfer(HGT)potentials.This study provides insights into the transfer mechanism,hosts,and control strategies of phyllosphere ARGs in typical plants.
文摘A bacterium capable of degrading dichlorvos was isolated from the rape phyllosphere and designated YD4. The strain was identified as Flavobacterium sp., based on its phenotypic features and 16S rRNA gene sequence. Strain YD4 was able to utilize dichlorvos as the sole source of phosphorus. In situ enhanced bioremedia- tion of dichlorvos by YD4 was hereafter studied. Chlorpyrifos and phoxim could also be degraded by this strain as the sole phosphorus source. A higher degradation rate of dichlorvos was observed after spraying YD4 onto the surface of rape leaves when compared to the sterilized- YD4 and water-treated samples. The results indicated that pesticide-degrading epiphytic bacterium could become a new way for in situ phyllosphere bioremediation where the hostile niche is unsuitable for other pesticide-degrading bacteria isolated from soil and water.
基金supported by the National Natural Science Foundation of China(Nos.21777144,21976161,41907210)the Changjiang Scholars and Innovative Research Team in University(No.IRT_17R97)。
文摘Chemical exposure can indirectly affect leaf microbiota communities,but the mechanism driving this phenomenon remains largely unknown.Results revealed that the co-exposure of glyphosate and multi-carbon nanotubes(CNTs)caused a synergistic inhibitory effect on the growth and metabolism of Arabidopsis thaliana shoots.However,only a slight inhibitory effect was induced by nanotubes or glyphosate alone at the tested concentrations.Several intermediate metabolites of nitrogen metabolism and fatty acid synthesis pathways were upregulated under the combined treatment,which increased the amount of energy required to alleviate the disruption caused by the combined treatment.Additionally,compared with the two individual treatments,the glyphosate/nanotube combination treatment induced greater fluctuations in the phyllosphere bacterial community members with low abundance(relative abundance(RA)<1%)at both the family and genus levels,and among these bacteria some plant growth promotion and nutrient supplement related bacteria were markable increased.Strikingly,strong correlations between phyllosphere bacterial diversity and metabolites suggested a potential role of leaf metabolism,particularly nitrogen and carbohydrate metabolism,in restricting the range of leaf microbial taxa.These correlations between phyllosphere bacterial diversity and leaf metabolism will improve our understanding of plant-microbe interactions and the extent of their drivers of variation and the underlying causes of variability in bacterial community composition.
基金supported by the National Natural Science Foundation of China (No.21177145, 20977106)the Key Laboratory of Pollution Processes and Environmental Criteria (Nankai University), Ministry of Education (No.KL-PPEC-2010-3)
文摘Bacterial populations coexisting in the phyllosphere niche have important effects on plant health. Quorum sensing (QS) allows bacteria to communicate via diffusible signal molecules, but QS-dependent behaviors in phyllosphere bacterial populations are poorly understood. We investigate the dense and diverse N-acyl-homoserine lactone (AHL)-producing phyllosphere bacteria living on tobacco leaf surfaces via a culture-dependent method and 16S rRNA gene sequencing. Our results indicated that approximately 7.9%-11.7% of the culturable leaf-associated bacteria have the ability to produce AHL based on the assays using whole-cell biosensors. Sequencing of the 16S rRNA gene assigned the AHL-producing strains to two phylogenetic groups, with Gammaproteobacteria (93%) as the predominant group, followed by Alphaproteobacteria. All of the AHL-producing Alphaproteobacteria were affiliated with the genus Rhizobium, whereas the AHL-producing bacteria belonging to the Gammaproteobacteria mainly fell within the genera Pseudomonas, Acinetobacter, Citrobacter, Enterobacter, Pantoea and Serratia. The bioassays of supernatant extracts revealed that a portion of the strains have a remarkable AHL profile for AHL induction activity using the two different biosensors, and one compound in the active extract of a representative isolate, NTL223, corresponded to 3-oxo-hexanoyl-homoserine lactone. A large population size and diversity of bacteria capable of AHL-driven QS were found to cohabit on leaves, implying that cross-communication based AHL-type QS may be common in the phyllosphere. Furthermore, this study provides a general snapshot of a potential valuable application of AHL-producing bacteria inhabiting leaves for their presumable ecological roles in the phyllosphere.
基金supported by the National Natural Science Foundation of China(Nos.21777144,21976161)the CAS Pioneer Hundred Talents Program(H.F.Qian)the Xinjiang Uighur Autonomous Region Talent Project(H.F.Qian)。
文摘Imazethapyr(IM)is a widely used acetolactate synthase-inhibiting chiral herbicide.It has long-term residuals that may be absorbed by the human body through the edible parts of plants,such as vegetable leaves or fruits.Here,we selected a model plant,Arabidopsis thaliana,to determine the effects of R-IM and S-IM on its leaf structure,photosynthetic efficiency,and metabolites,as well as the structures of microorganisms in the phyllosphere,after 7 days of exposure.Our results indicated enantiomeric differences in plant growth between R-IM and S-IM;133μg/kg R-IM showed heavier inhibition of photosynthetic efficiency and greater changes to subcellular structure than S-IM.R-IM and S-IM also had different effects on metabolism and leaf microorganisms.S-IM mainly increased lipid compounds and decreased amino acids,while R-IM increased sugar accumulation.The relative abundance of Moraxellaceae human pathogenic bacteria was increased by R-IM treatment,indicating that R-IM treatment may increase leaf surface pathogenic bacteria.Our research provides a new perspective for evaluating the harmfulness of pesticide residues in soil,phyllosphere microbiome changes via the regulation of plant metabolism,and induced pathogenic bacterial accumulation risks.
基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A351)the Joint Fund of National Natural Science Foundation of China(U2003214)+1 种基金the Key Project of Xinjiang Uygur Autonomous Region Natural Science Foundation(2022D01D083)the Tianchi Talent Introduction Project of Xinjiang Uygur Autonomous Region.We thank Mr.LI Yonggang,Mrs.DU Fang,Mrs.SHEN Hui,Mrs.PAN Qi,and Mrs.MENG Huanhuan for providing help with the experiment in the field.
文摘Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous.Utilizing high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest China.Functional annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities.Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal community.Comparison across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant characteristics.FAPROTAX prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form plants.FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa.Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly.Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted both bacterial and fungal community composition,with fungal community composition showing a closer association with leaf nutrients and physiology compared with bacterial community composition.The distinct responses of bacterial and fungal communities to plant traits were attributed to the differing properties of bacteria and fungi,such as bacteria having higher potential dispersal rates and broader ecological niches than fungi.Overall,the results indicate that phyllosphere bacterial and fungal communities undergo similar community assembly processes,with fungi being more influenced by plant characteristics than bacteria.These findings offer novel insights into the ecology of phyllosphere microbial communities of desert plants.
基金Supported by the National Natural Science Foundation of China(No.40730528)the National Basic Research Program of China(973Program)(No.2008CB418104)+2 种基金the Knowledge Innovation Project of Chinese Academy of Sciences(No.KZCX2-YW-JC302)the Jiangsu Provincial Science Foundation(No.BK2009024)the Frontier Foundation of Nanjing Institute of Geography & Limnology,Chinese Academy of Sciences(No.09SL021001)
文摘Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species. However, the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood. We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes: Vallisneria natans and Hydrilla verticillata in Taihu Lake, Jiangsu, China, using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes. The results show that: (1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria, and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria, including Burkholderiales, was the most abundant bacterial group on both plants. Cyanobacteria and Gammaproteobacteria were the second largest groups on V. natans and H. verticillata, respectively. Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations. Both ANOSIM of the T-RFLP data and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants. Therefore, the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific, which may aid in understanding the ecological functions of submerged macrophytes in general.
基金funded by Department of Biotechnology,Govt.of India,New Delhi under network project under NER-BPMC-DBT-NER/AGRI/33/2016.
文摘Endophytic fungal isolates(139 no.)were obtained from 143(62 roots,18 fruits and 54 leaves)samples of 15 different varieties of banana collected from 10 sites in Assam,India during 2018-2019.Overall isolation frequency from surface-sterilized tissue ranged from 10%-80%(as per site)and 6%-70%(as per variety of banana).All isolates were segregated into 40 different types on the basis of macromorphological and micro morphological characteristics.Forty different fungal taxa were isolated belonging to 14 genera including Absidia,Arthrinium,Aspergillus,Bipolaris,Cladosporium,Curvularia,Dendrophion,Fusarium,Humicola,Mortierella,Mucor,Penicillium,Paecilomyces,Verticillium and one mycelium sterile.Among them,Cladosporium cladosporioidies and Paecilomyces sp.frequently occurred in most of the sites surveyed whereas Cladospoirum cladosporioides and Aspergillus sp.8,Fusarium graminseram were most frequently isolated from different varieties.However,all sites differed in their fungal diversity.Banana samples from Narigoan and Jorhat have been found with maximum fungal species followed by marigoan samples so as to Banana varieties Amrit Sagar endowed 27 no.of fungi followed by Jehaji and Honda which were associated with a maximum 14 fungal sp.Isolation frequency and relative abundance of Cladosporium cladosporiodes(80%,4.6),Paecilomyces farinosus(80%,4.6)followed by Penicillium ruburm,Aspergillus sp.8&9(70%,4.02)were recorded as maximum comparatively in different sites.However,Aspergillus sp.8,Mortieralla sp.and Pacilomyces farinosus are isolated frequently from different banana varieties(73.33%,4.93).
基金supported by the National Natural Science Research Foundation of China(Grant No.32272040)the National Key R&D Program of China(Grant No.2022YFD1201702)+2 种基金the Natural Science Foundation Youth Project of Shandong Province(Grant No.ZR2022QC191)the Agricultural Fine Seed Project of Shandong Province(Grant No.2021LZGC006)the Special Funds for TaiShan Scholars(Grant No.tsqn202211106).
文摘Soil salinity is a worldwide problem threatening crop yields.Some plant growth-promoting rhizobacteria(PGPR)could survive in high salt environment and assist plant adaptation to stress.Nevertheless,the genomic and metabolic features,as well as the regulatory mechanisms promoting salt tolerance in plants by these bacteria remain largely unknown.In the current work,a novel halotolerant PGPR strain,namely,Bacillus sp.strain RA can enhance tomato tolerance to salt stress.Comparative genomic analysis of strain RA with its closely related species indicated a high level of evolutionary plasticity exhibited by strain-specific genes and evolutionary constraints driven by purifying selection,which facilitated its genomic adaptation to salt-affected soils.The transcriptome further showed that strain RA could tolerate salt stress by balancing energy metabolism via the reprogramming of biosynthetic pathways.Plants exude a plethora of metabolites that can strongly influence plant fitness.The accumulation of myo-inositol in leaves under salt stress was observed,leading to the promotion of plant growth triggered by Bacillus sp.strain RA.Importantly,myo-inositol serves as a selective force in the assembly of the phyllosphere microbiome and the recruitment of plant-beneficial species.It promotes destabilizing properties in phyllosphere bacterial co-occurrence networks,but not in fungal networks.Furthermore,interdomain interactions between bacteria and fungi were strengthened by myo-inositol in response to salt stress.This work highlights the genetic adaptation of RA to salt-affected soils and its ability to impact phyllosphere microorganisms through the adjustment of myo-inositol metabolites,thereby imparting enduring resistance against salt stress in tomato.
基金supported by the National Natural Science Foundation of China (No. 30600082)the Knowledge Innovation Program of Chinese Academy of Sciences (No.KSCX2-YW-G-054-2)the Key Technologies R&D Program of China (No. 2008BADA7B01)
文摘A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater (MGW) and potato wastewater (PW) as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW (1:9).
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.
基金supported by the National Natural Science Foundation of China(Nos.21777144,21577128)the CAS Pioneer Hundred Talents Program(H.F.Qian)the Xinjiang Uighur Autonomous Region Talent Project(H.F.Qian)
文摘Imazethapyr (IM) is an acetolactate synthase (ALS)-inhibiting herbicide that has been widely used in recent years.However,IM spraying can lead to the accumulation of herbicide residues in leaves.Here,we determined the effects of IM spraying on the plant growth and leaf surface microbial communities of Arabidopsis thaliana after 7 and 14 days of exposure.The results suggested that IM spraying inhibited plant growth.Fresh weight decreased to 48% and 26% of the control value after 7 and 14 days,respectively,of 0.035 kg/ha IM exposure.In addition,anthocyanin content increased 9.2-fold and 37.2-fold relative to the control content after 7 and 14 days of treatment,respectively.Furthermore,IM spraying destroyed the cell structures of the leaves,as evidenced by increases in the number of starch granules and the stomatal closure rate.Reductions in photosynthetic efficiency and antioxidant enzyme activity were observed after IM spraying,especially after 14 days of exposure.The diversity and evenness of the leaf microbiota were not affected by IM treatment,but the composition of community structure at the genus level was altered by IM spraying.Imazethapyr application increased the abundance of Pseudomonas,a genus that includes species pathogenic to plants and humans,indicating that IM potentially increased the abundance of pathogenic bacteria on leaves.Our findings increase our understanding of the relationships between herbicide application and the microbial community structures on plant leaves,and they provide a new perspective for studying the ecological safety of herbicide usage.