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1.
World J Microbiol Biotechnol ; 35(8): 128, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375920

RESUMO

Large patch disease, caused by Rhizoctonia solani AG2-2, is the most devastating disease in Zoysiagrass (Zoysia japonica). Current large patch disease control strategies rely primarily upon the use of chemical pesticides. Streptomyces sp. S8 is known to possess exceptional antagonistic properties that could potentially suppress the large patch pathogen found at turfgrass plantations. This study aims to demonstrate the feasibility of using the strain as a biological control mechanism. Sequencing of the S8 strain genome revealed a valinomycin biosynthesis gene cluster. This cluster is composed of the vlm1 and vlm2 genes, which are known to produce antifungal compounds. In order to verify this finding for the large patch pathogen, a valinomycin biosynthesis knockout mutant was created via the CRISPR/Cas9 system. The mutant lost antifungal activity against the large patch pathogen. Consequently, it is anticipated that eco-friendly microbial preparations derived from the S8 strain can be utilized to biologically control large patch disease.


Assuntos
Antifúngicos/metabolismo , Antifúngicos/farmacologia , Rhizoctonia/efeitos dos fármacos , Streptomyces/metabolismo , Valinomicina/metabolismo , Valinomicina/farmacologia , Vias Biossintéticas/genética , Técnicas de Inativação de Genes , Genoma Bacteriano , Família Multigênica , Controle Biológico de Vetores/métodos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Poaceae/microbiologia , Rhizoctonia/crescimento & desenvolvimento , Análise de Sequência de DNA , Streptomyces/genética
2.
J Environ Sci (China) ; 84: 133-143, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31284905

RESUMO

In this study, raw Arundo donax (A. donax) pieces were applied as carbon source and biofilm carriers for denitrification in a lab-scale moving bed biofilm reactor (MBBR) for the treatment of reverse osmosis concentrate gathered from local wastewater reuse plant. At stable phase (about 60 days), efficient denitrification performance was obtained with 73.2% ±â€¯19.5% NO3--N average removal and 8.10 ±â€¯3.45 g N/(m3·day) NO3--N average volumetric removal rate. Mass balance analysis showed that 4.84 g A. donax was required to remove 1 g TN. Quantitative real-time PCR analysis results showed that the copy numbers of 16S r-RNA, narG, nirS, nosZ and anammox gene of carrier biofilm and suspended activated sludge in the declination phase (BF2 and AS2) were lower than those of samples in the stable phase (BF1 and AS1), and relatively higher copy numbers of nirS and nirK genes with lower abundance of narG and nosZ genes were observed. High-throughput sequencing analysis was conducted for BF2 and AS2, and similar dominant phyla and classes with different abundance were obtained. The class Gammaproteobacteria affiliated with the phylum Proteobacteria was the most dominant microbial community in both BF2 (52.6%) and AS2 (41.7%). The PICRUSt prediction results indicated that 33 predictive specific genes were related to denitrification process, and the relative abundance of 18 predictive specific genes in BF2 were higher than those in AS2.


Assuntos
Reatores Biológicos/microbiologia , Desnitrificação , Consórcios Microbianos , Nitrogênio/isolamento & purificação , Poaceae/química , Poaceae/microbiologia , Purificação da Água
3.
Ecotoxicol Environ Saf ; 182: 109382, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31255867

RESUMO

Polycyclic aromatic hydrocarbons (PAH) have become a threat for the conservation of wetlands worldwide. The halophyte Spartina densiflora has shown to be potentially useful for soil phenanthrene phytoremediation, but no studies on bacteria-assisted hydrocarbon phytoremediation have been carried out with this halophyte. In this work, three phenanthrene-degrading endophytic bacteria were isolated from S. densiflora tissues and used for plant inoculation. Bacterial bioaugmentation treatments slightly improved S. densiflora growth, photosynthetic and fluorescence parameters. But endophyte-inoculated S. densiflora showed lower soil phenanthrene dissipation rates than non-inoculated S. densiflora (30% below) or even bulk soil (23% less). Our work demonstrates that endophytic inoculation on S. densiflora under greenhouse conditions with the selected PAH-degrading strains did not significantly increase inherent phenanthrene soil dissipation capacity of the halophyte. It would therefore be advisable to provide effective follow-up of bacterial colonization, survival and metabolic activity during phenanthrene soil phytoremediation.


Assuntos
Bactérias/metabolismo , Fenantrenos/análise , Poaceae/metabolismo , Plantas Tolerantes a Sal/metabolismo , Poluentes do Solo/análise , Solo/química , Biodegradação Ambiental , Endófitos/metabolismo , Fotossíntese , Poaceae/microbiologia , Plantas Tolerantes a Sal/microbiologia , Microbiologia do Solo , Áreas Alagadas
4.
Plant Dis ; 103(8): 2108-2112, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31215853

RESUMO

Clavibacter nebraskensis is the causal agent of Goss's leaf blight and wilt, an important disease of maize in the United States and Canada. The epidemiology and ecology of this bacterial pathogen are poorly understood. Infested maize residue is often considered to be the primary source of inoculum for maize; however, the potential for many other plant species to be infected and serve as inoculum sources is unknown. The goal of this study was to determine if C. nebraskensis could infect, survive, and grow on common weed, crop, and grass species. Seedling leaves of 18 plant species that grow in maize production areas in the United States were inoculated with this pathogen in a controlled environment and in the field. Lesion development, bacterial streaming, and pathogen population size on leaves were then determined and used as criteria to evaluate host-pathogen interactions. Woolly cupgrass (Eriochloa villosa) and the native prairie grasses big bluestem (Andropogon gerardii) and little bluestem (Schizachyrium scoparium) developed lesions and bacterial streaming, identifying them as hosts and susceptible to infection. To our knowledge, this is the first report of these grass species being hosts of C. nebraskensis. Ten other grass species, including wheat and oats, were identified as potential sustaining hosts that maintained epiphytic or endophytic pathogen populations >106 colony forming units per leaf sample but displayed no evidence of infection. Five broadleaf species tested were nonhosts based on the three criteria. This study suggests that multiple plant species support infection and growth of C. nebraskensis and further elucidates the ecology of this pathogen and the epidemiology of Goss's wilt.


Assuntos
Micrococcaceae , Plantas , Canadá , Pradaria , Especificidade de Hospedeiro , Viabilidade Microbiana , Micrococcaceae/crescimento & desenvolvimento , Micrococcaceae/fisiologia , Plantas/microbiologia , Poaceae/microbiologia , Zea mays/microbiologia
5.
Sci Total Environ ; 686: 264-275, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31181514

RESUMO

Seagrass meadows store globally-significant quantities of organic 'blue' carbon. These blue carbon stocks are potentially vulnerable to anthropogenic stressors (e.g. coastal development, climate change). Here, we tested the impact of oxygen exposure and warming (major consequences of human disturbance) on rates of microbial carbon break-down in seagrass sediments. Active microbes occurred throughout seagrass sediment profiles, but deep, ancient sediments (~5000 yrs. old) contained only 3% of the abundance of active microbes as young, surface sediments (<2 yrs. old). Metagenomic analysis revealed that microbial community structure and function changed with depth, with a shift from proteobacteria and high levels of genes involved in sulfur cycling in the near surface samples, to a higher proportion of firmicutes and euraracheota and genes involved in methanogenesis at depth. Ancient carbon consisted almost entirely (97%) of carbon considered 'thermally recalcitrant', and therefore presumably inaccessible to microbial attack. Experimental warming had little impact on carbon; however, exposure of ancient sediments to oxygen increased microbial abundance, carbon uptake and sediment carbon turnover (34-38 fold). Overall, this study provides detailed characterization of seagrass blue carbon (chemical stability, age, associated microbes) and suggests that environmental disturbances that expose coastal sediments to oxygen (e.g. dredging) have the capacity to diminish seagrass sediment carbon stocks by facilitating microbial remineralisation.


Assuntos
Mudança Climática , Poaceae/microbiologia , Organismos Aquáticos/microbiologia , Carbono/análise , Sequestro de Carbono , Oxigênio , Proteobactérias , Microbiologia da Água
6.
Curr Microbiol ; 76(7): 888-895, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31093691

RESUMO

Lindane is an organochlorine pesticide that is highly persistent in the environment. The amassing of lindane has been identified worldwide and has been found to be very toxic to the environment, human, and animal health. Therefore, urgent consideration and management of the problem is necessary. The current study intends to isolate and identify lindane degrading rhizospheric bacteria from Phragmites karka and to study its degradation kinetics. Also, plant growth promoting potential of the bacterium was evaluated in the presence and absence of studied pesticide. Rhizospheric bacteria were isolated by standard enrichment technique in Mineral Salt Medium. Microbacterium sp. P27 showed the highest degradation percentage, 82.7 ± 1.79% for 50 mg l-1 lindane, after 15 days. Degradation was also studied at different concentrations of lindane. Maximum degradation was achieved at 10 mg l-1 followed by 50 mg l-1 and 100 mg l-1 lindane. Microbacterium sp. P27 showed positive result for Indole-3-acetic acid production, ammonia production, and 1-aminocyclopropane-1-carboxylate deaminase activity. Presence of lindane revealed a concentration-dependent decrease in plant growth promoting activity. Since the isolated bacterial strain possesses lindane degrading capacity and also other characters that help in plant growth promotion, the isolate can be an important candidate for the progress of bioremediation strategy.


Assuntos
Actinomycetales/fisiologia , Hexaclorocicloexano/metabolismo , Reguladores de Crescimento de Planta/fisiologia , Plantas/microbiologia , Rizosfera , Microbiologia do Solo , Poluentes do Solo/metabolismo , Actinomycetales/metabolismo , Biodegradação Ambiental , Hexaclorocicloexano/toxicidade , Inseticidas/metabolismo , Inseticidas/toxicidade , Desenvolvimento Vegetal/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Poaceae/microbiologia , Poluentes do Solo/toxicidade
7.
J Microbiol ; 57(9): 725-731, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31124044

RESUMO

A Gram-staining-positive, motile and short-rod-shaped actinobacterium designated 9W16Y-2T was isolated from surface-sterilized leaves of reed (Phragmites australis) collected from Taklamakan Desert in Xinjiang Uygur Autonomous Region, China. Colonies were pale greenish yellow, circular, smooth, and convex. The 16S rRNA gene sequence of strain 9W16Y-2T exhibited highest sequence similarities with Aeromicrobium camelliae CGMCC 1.12942T (99.0%) and Aeromicrobium erythreum NRRL B-3381T (97.2%). Phylogenetic analyses based on 16S rRNA gene sequences and single-copy phylogenetic marker genes (pMGs) showed that strain 9W16Y-2T belonged to the genus Aeromicrobium and formed a monophyletic clade with Aeromicrobium camelliae CGMCC 1.12942T. Furthermore, average nucleotide identity (ANI) and DNA-DNA hybridization (DDH) clearly separated strain 9W16Y-2T from the other species of the genus Aeromicrobium with values below the thresholds for species delineation. The G+C content of the genomic DNA is 68.9 mol%. The diagnostic diamino acid of the cell-wall peptidoglycan was LL-diaminopimelic acid. The predominant menaquinone was MK-9(H4). The major fatty acids (> 10% of the total fatty acids) were C18:0 10-methyl (TBSA) (28.2%), C16:0 (21.0%), C16:0 2-OH (20.8%) and C18:1ω9c (12.8%). The polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, an unidentified aminophospholipid and an unidentified lipid. Based on the phylogenic, phenotypic and chemotaxonomic features, strain 9W16Y-2T represents a novel species of the genus Aeromicrobium, for which the name Aeromicrobium endophyticum sp. nov. is proposed. The type strain is 9W16Y-2T (= CGMCC 1.13876T = JCM 33141T).


Assuntos
Actinobacteria/isolamento & purificação , Endófitos/isolamento & purificação , Poaceae/microbiologia , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/metabolismo , Técnicas de Tipagem Bacteriana , Parede Celular/química , Parede Celular/metabolismo , China , DNA Bacteriano/genética , Endófitos/classificação , Endófitos/genética , Endófitos/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Peptidoglicano/química , Peptidoglicano/metabolismo , Filogenia , RNA Ribossômico 16S/genética
8.
Environ Int ; 129: 105-117, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31125730

RESUMO

Understanding how microbial communities change with environmental degradation and restoration may offer new insights into the understudied ecology that connects humans, microbiota, and the natural world. Immunomodulatory microbial diversity and 'Old Friends' are thought to be supplemented from biodiverse natural environments, yet deficient in anthropogenically disturbed or degraded environments. However, few studies have compared the microbiomes of natural vs. human-altered environments and there is little knowledge of which microbial taxa are representative of ecological restoration-i.e. the assisted recovery of degraded ecosystems typically towards a more natural, biodiverse state. Here we use novel bootstrap-style resampling of site-level soil bacterial 16S rRNA gene environmental DNA data to identify genus-level indicators of restoration from a 10-year grassy eucalypt woodland restoration chronosequence at Mt Bold, South Australia. We found two key indicator groups emerged: 'opportunistic taxa' that decreased in relative abundance with restoration and more stable and specialist, 'niche-adapted taxa' that increased. We validated these results, finding seven of the top ten opportunists and eight of the top ten niche-adapted taxa displayed consistent differential abundance patterns between human-altered vs. natural samples elsewhere across Australia. Extending this, we propose a two-dimensional mapping for ecosystem condition based on the proportions of these divergent indicator groups. We also show that restoring a more biodiverse ecosystem at Mt Bold has increased the potentially immune-boosting environmental microbial diversity. Furthermore, environmental opportunists including the pathogen-containing genera Bacillus, Clostridium, Enterobacter, Legionella and Pseudomonas associated with disturbed ecosystems. Our approach is generalizable with potential to inform DNA-based methods for ecosystem assessment and help target environmental interventions that may promote microbiota-mediated human health gains.


Assuntos
Ecossistema , Florestas , Microbiota , Poaceae/microbiologia , Austrália , Biodiversidade , Humanos , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo
9.
World J Microbiol Biotechnol ; 35(6): 81, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31134389

RESUMO

TiO2 nanoparticles (TiO2NPs) is one of the most widely used nanomaterials. Arbuscular mycorrhizal fungi (AMF) are an important and widely distributed group of soil microorganisms, which promote the absorption of nutrients by host plants and increase their tolerance to contaminants. However, the effects and mechanisms of AMF on plant TiO2NPs tolerance in wetland habitats are not clear. In this experiment, under the conditions of three soil moisture contents (drought 50%, normal 70% and flooding 100%) and four TiO2NPs concentrations (0, 100, 200 and 500 mg kg-1), the effects of Funneliformis mosseae on the growth, antioxidant enzyme activities, osmotic substances and the absorption and accumulation of Ti in the Phragmites australis (reed) seedlings were studied. The results showed that the inoculation of F. mosseae under three moisture content conditions significantly increased the plant nutrition and root activities of reeds. Compared with the non-inoculated control, inoculation with F. mosseae increased the activities of antioxidant enzymes, the contents of chlorophyll, proline, soluble protein, and free amino acids, and significantly reduced the contents of malondialdehyde (MDA) and reactive oxygen species (ROS) of leaves. The accumulating ability of inoculated reeds to Ti was significantly higher than that of non-inoculated controls (P < 0.05), and inoculation of F. mosseae changed the distribution of Ti in reeds, increased the accumulation of Ti in roots. It's confirmed that inoculation of F. mosseae under three water conditions could improve the plant growth and nutrition, the activities of antioxidant enzymes, and enhance the reeds tolerance to TiO2NPs in this study.


Assuntos
Glomeromycota/fisiologia , Nanopartículas/toxicidade , Poaceae/efeitos dos fármacos , Poaceae/microbiologia , Plântula/crescimento & desenvolvimento , Estresse Fisiológico , Titânio/toxicidade , Água/metabolismo , Aminoácidos/metabolismo , Antioxidantes/metabolismo , Clorofila/metabolismo , Secas , Tolerância a Medicamentos , Malondialdeído/metabolismo , Osmose , Desenvolvimento Vegetal , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/microbiologia , Microbiologia do Solo , Áreas Alagadas
10.
Curr Microbiol ; 76(7): 824-834, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31020346

RESUMO

An edible gall is formed between the third and fourth nodes beneath the apical meristem near the base of Zizania latifolia shoots. This gall is harbored by and interacts with the smut fungus Ustilago esculenta. The gall is also a valuable vegetable called "white bamboo," jiaobai or gausun in China and makomotake in Japan. Five samples of the galls harvested at different stages of swelling were used to isolate microorganisms by culturing. Isolated fungal and bacterial colonies were identified by DNA sequencing and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, respectively. Several strains of U. esculenta as well as 6 other species of fungi and 10 species of bacteria were isolated. The microbiome was also evaluated by simple and outlined DNA profiling with automated rRNA intergenic spacer analysis (ARISA), and the amount of DNA of U. esculenta was determined by qPCR. At least 16 species of fungi and 40 species of bacteria were confirmed by ARISA of the overall sample. Interestingly, the greatest bacterial diversity, i.e., 18 species, was observed in the most mature sample, whereas the fungal diversity observed in this sample, i.e., 4 species, was rather poor. Based on qPCR, U. esculenta occurred in samples from all stages; however, the abundance of U. esculenta exhibited unique U-shaped relationships with growth. These results may explain why the interaction between U. esculenta and Z. latifolia also influences the unique microbial diversity observed throughout the growth stages of the swollen shoot, although the limited sample size does not allow conclusive findings.


Assuntos
Biodiversidade , Interações entre Hospedeiro e Microrganismos/fisiologia , Caules de Planta/microbiologia , Poaceae/microbiologia , Ustilago/fisiologia , Verduras/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , DNA Espaçador Ribossômico/genética , Microbiota/genética , Caules de Planta/crescimento & desenvolvimento , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA , Ustilago/classificação , Ustilago/genética , Ustilago/isolamento & purificação , Verduras/crescimento & desenvolvimento
11.
J Basic Microbiol ; 59(6): 609-620, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30980724

RESUMO

Revegetation is widely used to enhance degraded topsoil recovery with the enhancements of soil nutrient accumulation and soil structure stabilization. Arbuscular mycorrhizal fungi (AMF) are important for the allocation of carbon into the soil and the formation of soil aggregates. Thus, we hypothesized that AMF could construct more niches for other microbes during revegetation, making AMF keystone taxa of soil. Soil fungal and bacterial communities were investigated under a revegetation experiment and correlation networks between soil fungi and bacteria were constructed. Simultaneously, the plant growth level, soil properties and structure, and soil microbial carbon decomposition abilities were measured. The results revealed that AMF were the most central fungi at the phylum (degree = 3), class (degree = 11), and family (degree = 15) levels. The reads number of AMF were positively correlated with both fungal (R2 = 0.431, P < 0.001) and bacterial (R2 = 0.106, P = 0.044) richness. Higher colonization of AMF in roots and/or more AMF extraradical mycelium and spores in soil indicated a better plant growth, more stable soil aggregates, and a higher carbon decomposition ratio. Our results highlight that AMF are keystone taxa in revegetation, as they play significant roles in enhancing the recovery of the belowground microbiome diversity, soil structure stability, and nutrients cycling. The positive roles of AMF in revegetation support the application of AMF in ecosystem recovery.


Assuntos
Recuperação e Remediação Ambiental , Microbiota , Micorrizas/fisiologia , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Carbono/metabolismo , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Micorrizas/classificação , Micorrizas/crescimento & desenvolvimento , Micorrizas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Solo/química , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Tibet
12.
Artigo em Inglês | MEDLINE | ID: mdl-30708940

RESUMO

Ecological stoichiometry has been widely used to determine how plant-soil systems respond to global change and to reveal which factors limit plant growth. Arbuscular mycorrhizal fungi (AMF) can increase plants' uptake of nutrients such as nitrogen (N) and phosphorus (P), thereby altering plant and soil stoichiometries. To understand the regulatory effect of AMF feedback on plants and soil stoichiometry under global change, a microcosm experiment was conducted with warming and N input. The C4 grass Setaria viridis, C3 grass Leymus chinensis, and Chenopodiaceae species Suaeda corniculata were studied. The results showed that the mycorrhizal benefits for the C4 grass S. viridis were greater than those for the C3 grass L. chinensis, whereas for the Chenopodiaceae species S. corniculata, AMF symbiosis was antagonistic. Under N input and a combination of warming and N input, AMF significantly decreased the N:P ratios of all three species. Under N input, the soil N content and the N:P ratio were decreased significantly in the presence of AMF, whereas the soil C:N ratio was increased. These results showed that AMF can reduce the P limitation caused by N input and improve the efficiency of nutrient utilization, slow the negative influence of global change on plant growth, and promote grassland sustainability.


Assuntos
Mudança Climática , Micorrizas/fisiologia , Nutrientes/metabolismo , Poaceae/metabolismo , Solo/química , China , Pradaria , Nitrogênio/análise , Nitrogênio/metabolismo , Nutrientes/análise , Fósforo/análise , Fósforo/metabolismo , Poaceae/classificação , Poaceae/microbiologia , Especificidade da Espécie
13.
Mar Pollut Bull ; 140: 171-178, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30803632

RESUMO

Microbial communities in wetland soils play vital roles in biogeochemical cycling of nutrients. In this study, the soil samples were collected from Suaeda, reed and Suaeda-reed hybrid zones in Shuangtaizi River Estuary, Northeast China, and the rhizosphere bacterial communities were compared using Illumina MiSeq sequencing. The microbial richness, diversity and structure of bacterial communities varied greatly in reed and Suaeda. Canonical correspondence analysis and Mantel test indicated that pH was the most significant factor (P < 0.05) in bacterial community assembly. Proteobacteria was the most dominant phylum, accounting for 45.7-58.0% of the total sequences. Thioprofundum, Thiohalomonas and Exiguobacterium were the predominant genera in Suaeda, while Exiguobacterium, Gillisia, Desulfomonile, Citrobacter, Thioprofundum and Acinetobacter were the core species in reed. PICRUSt analysis revealed similar functional profiles of rhizosphere microbiota in reed and Suaeda. Nitrate reduction related genes were abundant for nitrogen metabolism, whereas assimilatory sulfate reduction was the major process for sulfur metabolism.


Assuntos
Chenopodiaceae/microbiologia , Microbiota , Poaceae/microbiologia , Proteobactérias/isolamento & purificação , Rizosfera , Microbiologia do Solo , Áreas Alagadas , Chenopodiaceae/crescimento & desenvolvimento , China , Estuários , Poaceae/crescimento & desenvolvimento , Rios , Solo/química
14.
Antonie Van Leeuwenhoek ; 112(7): 1087-1094, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30707396

RESUMO

In this study, a Gram-negative, rod-shaped, endophytic bacterial strain (RS1T) capable of producing large amounts of exopolysaccharides was isolated from a stem of Miscanthus sinensis. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RS1T is closely related to Mucilaginibacter kameinonensis NBRC 102645T (98.72%), followed by Mucilaginibacter gossypiicola Gh-48T (97.56%) and Mucilaginibacter oryzae DSM 19975T (97.36%). The DNA G + C content of strain RS1T was determined to be 42.80 mol%. ANIb and GGDC values from genomic comparison between the genomes of strain RS1T and the related reference species were less than 95% and 70%, respectively. The major cellular fatty acids (more than 10% of total fatty acids) were identified as iso-C15: 0, C16:0, iso-C17:0-3OH and summed feature 3 (C16: 1ω7c and/or iso-C15:02-OH). The only isoprenoid quinone detected was MK-7. Based on the physiological, genotypic and genomic characteristics, strain RS1T is concluded to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter endophyticus sp. nov. is proposed (type strain RS1T = KCTC 62785T = GDMCC 1.1414T).


Assuntos
Bacteroidetes/isolamento & purificação , Endófitos/isolamento & purificação , Poaceae/microbiologia , Polissacarídeos/metabolismo , Técnicas de Tipagem Bacteriana , Bacteroidetes/classificação , Bacteroidetes/genética , Bacteroidetes/metabolismo , Composição de Bases , DNA Bacteriano/genética , Endófitos/classificação , Endófitos/genética , Endófitos/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Filogenia , Caules de Planta/microbiologia , RNA Ribossômico 16S/genética
15.
Curr Microbiol ; 76(3): 338-345, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30680440

RESUMO

The diversities of soil bacterial communities in the Phragmites australis, Phalaris arundinacea, and non-plantation constructed wetlands were compared and analyzed by through high-throughput Illumina sequencing. At the phylum level, the ten dominant bacterial phyla in the three types of constructed wetlands were the same. At the genus level, the three most dominant bacterial genera in the three types of constructed wetlands were the same. The non-plantation constructed wetland (Nop-cw) had the highest diversity of soil bacterial community. The introduction of P. australis or P. arundinacea did not increase diversity of the soil bacterial communities in the constructed wetlands but greatly changed the compositions and potential function of the soil bacterial communities, especially some bacterial genera involved in pollutant removal. So it was predicted that the P. australis constructed wetland (Pau-cw) had a larger capacity for the removal of heavy metals and sulfur than the P. arundinacea constructed wetland (Par-cw), and the nitrification capacity of the P. arundinacea constructed wetland was stronger than that of the P. australis constructed wetland. The above results not only clarified the differences among the soil bacterial communities of the constructed wetlands with different plants in terms of diversity but also revealed the decontamination mechanism of the constructed wetlands to some degree.


Assuntos
Bactérias/metabolismo , Biodiversidade , Poaceae/microbiologia , Microbiologia do Solo , Poluentes do Solo/metabolismo , Áreas Alagadas , Bactérias/classificação , Biodegradação Ambiental , Ambiente Construído , Metais Pesados/metabolismo , Microbiota , Nitrificação , Poaceae/classificação , Especificidade da Espécie , Enxofre/metabolismo
16.
Am J Vet Res ; 80(1): 87-94, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30605026

RESUMO

OBJECTIVE To determine whether Mycobacterium bovis remains viable in ensiled forages. SAMPLE Alfalfa, mixed mostly grass, and corn silages. PROCEDURES For each of 10 sampling days, six 250-g replicate samples of each feedstuff were created and placed in a film pouch that could be vacuum sealed to simulate the ensiling process. Within each set of replicate samples, 4 were inoculated with 10 mL of mycobacterial liquid culture medium containing viable M bovis and 2 were inoculated with 10 mL of sterile mycobacterial liquid culture medium (controls) on day 0. Pouches were vacuum sealed and stored in the dark at room temperature. On the designated sampling day, 1 control pouch was submitted for forage analysis, and the other pouches were opened, and forage samples were obtained for M bovis culture and analysis with a PCR assay immediately and 24 hours later. RESULTS None of the control samples had positive M bovis culture or PCR assay results. Among M bovis-inoculated samples, the organism was not cultured from alfalfa and corn silage for > 2 days but was cultured from mixed mostly grass silage for 28 days after inoculation and ensiling initiation. Mycobacterium bovis DNA was detected by PCR assay in samples of all 3 feedstuffs throughout the 112-day observation period. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that properly ensiled forages would be an unlikely source for M bovis transmission to cattle. Further research is necessary to determine whether ensiling kills M bovis or forces it to become dormant and, if the latter, elucidate the conditions that cause it to revert to an infectious state.


Assuntos
Ração Animal/microbiologia , Criação de Animais Domésticos , Microbiologia de Alimentos , Mycobacterium bovis/fisiologia , Animais , Bovinos , Medicago/microbiologia , Medicago sativa/microbiologia , Poaceae/microbiologia , Silagem/microbiologia , Tuberculose Bovina/microbiologia , Zea mays/microbiologia
17.
Plant Dis ; 103(3): 411-416, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30605001

RESUMO

Sclerotinia sclerotiorum causes Sclerotinia stem rot (SSR) (also called white mold), resulting in stem rot and death of many common herbaceous ornamental plant species. Resistant plants would be useful to manage SSR; however, the host range of S. sclerotiorum is unclear. The goal of this study was to determine how the ornamental graminoids Pennisetum glaucum, Setaria italica, Juncus inflexus, Carex flagellifera, Isolepis cernua, and Acorus gramineus respond to inoculation with S. sclerotiorum. Plants were inoculated in the field and in controlled environments at 13, 16, 19, or 22°C with or without wounding, and evaluated for SSR. Inoculated detached leaves were stained to examine infection and oxalate oxidase production. A. gramineus developed SSR in field and controlled environments. Sclerotinia stem rot was not observed on P. glaucum in field environments. The disease developed on P. glaucum and S. italica in controlled environments, and severity increased with decreasing temperature and wounding. J. inflexus, C. flagellifera, and I. cernua developed no or minor symptoms of SSR in field and controlled environments. Mycelia penetrated A. gramineus leaves 24 h after inoculation (HAI) and P. glaucum at 48 HAI, but did not penetrate J. inflexus at 24, 48, or 96 HAI. Oxalate oxidase was not detected in inoculated leaves of these ornamental graminoids. The results illuminate S. sclerotiorum's interactions with monocots and broaden the understanding of SSR resistance in ornamental grasses.


Assuntos
Ascomicetos , Doenças das Plantas , Poaceae , Ascomicetos/fisiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Poaceae/microbiologia
18.
Toxins (Basel) ; 11(1)2018 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-30587763

RESUMO

Alkaloids are usually thought to be responsible for protecting endophyte-infected (EI) grasses from their herbivores. For EI grasses that produce few alkaloids, can endophyte infection enhance their resistance to herbivores? Related studies are limited. In the Inner Mongolian steppe, Achnatherum sibiricum is highly infected by Epichloë endophytes, but produces few alkaloids. Locusts are the common insect herbivores of grasses. In this study, A. sibiricum was used as plant material. Methyl jasmonate (MJ, when applied exogenously, can induce responses similar to herbivore damage) treatment was performed. The effects of endophyte infection and MJ treatment on the resistance of A. sibiricum to Locusta migratoria were studied. We found that locusts preferred EF (endophyte-free) plants to EI plants in both choice and no-choice feeding experiments. Endophyte infection enhanced the resistance of A. sibiricum to locusts. Endophyte infection decreased soluble sugar concentrations, while it increased the total phenolic content and phenylalanine ammonia lyase (PAL) activity, which may contribute to the resistance of A. sibiricum to locusts. There was an interaction effect between MJ treatment and endophyte infection on the growth of the host. MJ treatment was a negative regulator of the plant growth-promoting effects of endophyte infection. There was no interaction effect between MJ treatment and endophyte infection on the defense characteristics of the host. In groups not exposed to locusts, MJ treatment and endophyte infection had a similar effect in decreasing the soluble sugar content, while increasing the total phenolic content and the PAL activity. In groups exposed to locusts, the effect of MJ treatment on the above characteristics disappeared, while the effect of endophyte infection became more obvious. All of these results suggest that even for endophytes producing few alkaloids, they could still increase the resistance of native grasses to insect herbivores. Furthermore, endophyte infection might mediate the defense responses of the host, independent of jasmonic acid (JA) pathways.


Assuntos
Acetatos/farmacologia , Ciclopentanos/farmacologia , Endófitos , Epichloe , Gafanhotos/fisiologia , Herbivoria , Oxilipinas/farmacologia , Poaceae/efeitos dos fármacos , Poaceae/microbiologia , Animais , Compostos Fitoquímicos/metabolismo , Poaceae/crescimento & desenvolvimento , Poaceae/metabolismo
19.
Ying Yong Sheng Tai Xue Bao ; 29(12): 4145-4151, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30584743

RESUMO

Endophytic fungi and arbuscular mycorrhizal (AM) fungi are important components of grassland ecosystem. Endophytes can reduce colonization rates of their host plants by AM fungi. In this study, Achnatherum sibiricum, infected by Epichlo sibiricum (Es) or E. gansuensis (Eg), was adopted as experimental material. The effect of Epichlo endophyte culture filtrate, root exudates and aqueous extracts from the leaves (including fresh and dead leaves) on the spore germination rates of AM fungi (Glomus mosseae and Glomus etunicatum) were evaluated. The results showed that culture filtration of Epichlo endophyte significantly inhibited the germination rate of AM fungi spores. Root exudates of infected plants only significantly inhibited the germination of G. etunicatum spores, and such effect was not related to the endophytic species. The leaf aqueous extracts had no significant effect on the germination rate of G. mosseae spores. Only the aqueous extract of Es-infected dead leaves significantly reduced the spore germination rate of G. etunicatum. In natural ecosystem, Epichlo endophytes are normally internally hosted in plants, which may affect the spore germination of AM fungi by affecting the root exudates of the host plants.


Assuntos
Endófitos , Micorrizas , Raízes de Plantas/microbiologia , Poaceae/microbiologia , Fungos , Glomeromycota , Esporos Fúngicos
20.
BMC Genomics ; 19(1): 705, 2018 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-30253736

RESUMO

BACKGROUND: Powdery mildew (PM) is one of the most important and widespread plant diseases caused by biotrophic fungi. Notably, while monocot (grass) PM fungi exhibit high-level of host-specialization, many dicot PM fungi display a broad host range. To understand such distinct modes of host-adaptation, we sequenced the genomes of four dicot PM biotypes belonging to Golovinomyces cichoracearum or Oidium neolycopersici. RESULTS: We compared genomes of the four dicot PM together with those of Blumeria graminis f.sp. hordei (both DH14 and RACE1 isolates), B. graminis f.sp. tritici, and Erysiphe necator infectious on barley, wheat and grapevine, respectively. We found that despite having a similar gene number (6620-6961), the PM genomes vary from 120 to 222 Mb in size. This high-level of genome size variation is indicative of highly differential transposon activities in the PM genomes. While the total number of genes in any given PM genome is only about half of that in the genomes of closely related ascomycete fungi, most (~ 93%) of the ascomycete core genes (ACGs) can be found in the PM genomes. Yet, 186 ACGs were found absent in at least two of the eight PM genomes, of which 35 are missing in some dicot PM biotypes, but present in the three monocot PM genomes, indicating remarkable, independent and perhaps ongoing gene loss in different PM lineages. Consistent with this, we found that only 4192 (3819 singleton) genes are shared by all the eight PM genomes, the remaining genes are lineage- or biotype-specific. Strikingly, whereas the three monocot PM genomes possess up to 661 genes encoding candidate secreted effector proteins (CSEPs) with families containing up to 38 members, all the five dicot PM fungi have only 116-175 genes encoding CSEPs with limited gene amplification. CONCLUSIONS: Compared to monocot (grass) PM fungi, dicot PM fungi have a much smaller effectorome. This is consistent with their contrasting modes of host-adaption: while the monocot PM fungi show a high-level of host specialization, which may reflect an advanced host-pathogen arms race, the dicot PM fungi tend to practice polyphagy, which might have lessened selective pressure for escalating an with a particular host.


Assuntos
Ascomicetos/genética , Genoma Fúngico , Especificidade de Hospedeiro/genética , Doenças das Plantas/microbiologia , Adaptação Fisiológica , Ascomicetos/classificação , Ascomicetos/patogenicidade , Deleção de Genes , Perfilação da Expressão Gênica , Genes Fúngicos , Tamanho do Genoma , Sequenciamento de Nucleotídeos em Larga Escala , Micélio/genética , Micélio/metabolismo , Técnicas de Tipagem Micológica , Poaceae/microbiologia
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