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1.
Ecotoxicol Environ Saf ; 202: 110958, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800230

RESUMO

Phytoremediation is an effective way to repair heavy metal contaminated soil and rhizosphere microorganisms play an important role in plant regulation. Nevertheless, little information is known about the variation of microbial metabolic activities and community structure in rhizosphere during phytoremediation. In this study, the rhizosphere soil microbial metabolic activities and community structure of Trifolium repensL. during Cd-contaminated soil phytoremediation, were analyzed by Biolog EcoPlate™ and high-throughput sequencing. The uptake in the roots of Trifolium repensL. grown in 5.68 and 24.23 mg/kg Cd contaminated soil was 33.51 and 84.69 mg/kg respectively, causing the acid-soluble Cd fractions decreased 7.3% and 5.4%. Phytoremediation significantly influenced microbial community and Trifolium repensL. planting significantly increased the rhizosphere microbial population, diversity, the relative abundance of plant growth promoting bacteria (Kaistobacter and Flavisolibacter), and the utilization of difficultly metabolized compounds. The correlation analysis among substrate utilization and microbial communities revealed that the relative abundance increased microorganisms possessed stronger carbon utilization capacity, which was beneficial to regulate the stability of plant-microbial system. Collectively, the results of this study provide fundamental insights into the microbial metabolic activities and community structure during heavy metal contaminated soil phytoremediation, which may aid in the bioregulation of phytoremediation.


Assuntos
Cádmio/toxicidade , Microbiota/efeitos dos fármacos , Rizosfera , Microbiologia do Solo , Poluentes do Solo/toxicidade , Solo/química , Trifolium/efeitos dos fármacos , Biodegradação Ambiental , Cádmio/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poluentes do Solo/metabolismo , Trifolium/crescimento & desenvolvimento , Trifolium/metabolismo , Trifolium/microbiologia
2.
PLoS One ; 15(8): e0237194, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760135

RESUMO

We aimed to profile the metabolism of soybean roots that were infected with soybean cyst nematodes and treated with Bacillus simplex to identify metabolic differences that may explain nematode resistance. Compared with control soybean roots, B. simplex-treated soybean roots contained lower levels of glucose, fructose, sucrose, and trehalose, which reduced the nematodes' food source. Furthermore, treatment with B. simplex led to higher levels of melibiose, gluconic acid, lactic acid, phytosphingosine, and noradrenaline in soybean roots, which promoted nematocidal activity. The levels of oxoproline, maltose, and galactose were lowered after B. simplex treatment, which improved disease resistance. Collectively, this study provides insight into the metabolic alterations induced by B. simplex treatment, which affects the interactions with soybean cyst nematodes.


Assuntos
Bacillus/patogenicidade , Resistência à Doença , Metaboloma , Nematoides/patogenicidade , Soja/parasitologia , Animais , Metabolismo dos Carboidratos , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Raízes de Plantas/parasitologia , Soja/metabolismo , Soja/microbiologia
3.
PLoS One ; 15(8): e0236796, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780734

RESUMO

It is well-known that different plant species, and even plant varieties, promote different assemblages of the microbial communities associated with them. Here, we investigate how microbial communities (bacteria and fungi) undergo changes within the influence of woody plants (two olive cultivars, one tolerant and another susceptible to the soilborne fungal pathogen Verticillium dahliae, plus wild Holm oak) grown in the same soil but with different management (agricultural versus native). By the use of metabarcoding sequencing we determined that the native Holm oak trees rhizosphere bacterial communities were different from its bulk soil, with differences in some genera like Gp4, Gp6 and Solirubrobacter. Moreover, the agricultural management used in the olive orchard led to belowground microbiota differences with respect to the natural conditions both in bulk soils and rhizospheres. Indeed, Gemmatimonas and Fusarium were more abundant in olive orchard soils. However, agricultural management removed the differences in the microbial communities between the two olive cultivars, and these differences were minor respect to the olive bulk soil. According to our results, and at least under the agronomical conditions here examined, the composition and structure of the rhizospheric microbial communities do not seem to play a major role in olive tolerance to V. dahliae.


Assuntos
Microbiota/genética , Olea/microbiologia , Quercus/microbiologia , Microbiologia do Solo , DNA Fúngico/química , DNA Fúngico/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Raízes de Plantas/microbiologia , Análise de Componente Principal , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Rizosfera , Análise de Sequência de DNA , Verticillium/genética , Verticillium/patogenicidade
4.
PLoS One ; 15(8): e0234099, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810132

RESUMO

Two common ecological assumptions are that host generalist and rare species are poorer competitors relative to host specialist and more abundant counterparts. While these assumptions have received considerable study in both plant and animals, how they apply to ectomycorrhizal fungi remains largely unknown. To investigate how interspecific competition may influence the anomalous host associations of the rare ectomycorrhizal generalist fungus, Suillus subaureus, we conducted a seedling bioassay. Pinus strobus seedlings were inoculated in single- or two-species treatments of three Suillus species: S. subaureus, S. americanus, and S. spraguei. After 4 and 8 months of growth, seedlings were harvested and scored for mycorrhizal colonization as well as dry biomass. At both time points, we found a clear competitive hierarchy among the three ectomycorrhizal fungal species: S. americanus > S. subaureus > S. spraguei, with the competitive inferior, S. spraguei, having significantly delayed colonization relative to S. americanus and S. subaureus. In the single-species treatments, we found no significant differences in the dry biomasses of P. strobus seedlings colonized by each Suillus species, suggesting none was a more effective plant symbiont. Taken together, these results indicate that the rarity and anomalous host associations exhibited by S. subaureus in natural settings are not driven by inherently poor competitive ability or host growth promotion, but that the timing of colonization is a key factor determining the outcome of ectomycorrhizal fungal competitive interactions.


Assuntos
Micorrizas/crescimento & desenvolvimento , Pinus/microbiologia , Simbiose/fisiologia , Basidiomycota/classificação , Basidiomycota/genética , Basidiomycota/crescimento & desenvolvimento , Biomassa , Interações entre Hospedeiro e Microrganismos/fisiologia , Especificidade de Hospedeiro/genética , Especificidade de Hospedeiro/fisiologia , Pinus/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia
5.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1356-1364, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748593

RESUMO

Salinity is the most important factor for the growth of crops. It is an effective method to alleviate the toxic effect caused by salt stress using saline-alkali-tolerant and growth-promoting bacteria in agriculture. Seven salt-tolerant bacteria were screened from saline-alkali soil, and the abilities of EPS production, alkalinity reduction and IAA production of the selected strains were investigated. A dominant strain DB01 was evaluated. The abilities of EPS production, alkalinity reduction and IAA production of strain DB01 were 0.21 g/g, 8.7% and 8.97 mg/L, respectively. The isolate was identified as Halomonas aquamarina by partial sequencing analysis of its 16S rRNA genes, and had the ability to inhibit the growth of Fusarium oxysporum f. sp., Alternaria solani, Phytophthora sojae and Rhizoctonia cerealis. It also could promote root length and germination rate of wheat seedlings under salt stress. Halomonas aquamarina can provide theoretical basis for the development of soil microbial resources and the application in saline-alkali soil improvement.


Assuntos
Álcalis , Raízes de Plantas , Tolerância ao Sal , Microbiologia do Solo , Álcalis/metabolismo , Bactérias/efeitos dos fármacos , Bactérias/genética , Halomonas/genética , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Tolerância ao Sal/genética , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Solo/química , Triticum/microbiologia
6.
PLoS One ; 15(7): e0235932, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645087

RESUMO

We tested whether post-fire seedling establishment of common boreal tree and expanding shrub species at treeline and in Arctic tundra is facilitated by co-migration of boreal forest mycorrhizal fungi. Wildfires are anticipated to facilitate biome shifts at the forest-tundra ecotone by improving seedbed conditions for recruiting boreal species; at the same time fire alters the composition and availability of mycorrhizal fungi critical to seedling performance. To determine the role of root-associated fungi (RAF) in post-fire seedling recruitment and future biome shifts, we outplanted four dominant boreal tree and shrub species inoculated with one of three treatments at treeline and in tundra: burned boreal forest, unburned boreal forest, or a control treatment of sterilized inoculum. We compared survivorship, growth, and physiological performance of the seedlings in relation to mycorrhizal inoculum treatment and among host species, characterized the RAF communities based on ITS-rDNA sequencing of individual root tips sampled from surviving seedlings, and tested for correlations between RAF composition and the inoculation treatments, host species, and duration of the experiment. We explored correlations between RAF composition and seedling metrics. Both live and sterile autoclaved inoculation treatments had similar effects on seedling survivorship and growth for all species. RAF composition did not vary by treatment, suggesting that most colonization was due to local fungi. However, seedling traits and growth were correlated with RAF species composition, colonization, and the relative abundance of specific RAF taxa. Picea sp. performance in particular showed strong co-variation with RAF metrics. Our results suggest that mycorrhizal co-migration is not a primary limiting factor to boreal seedling recruitment because the experimental provision of inoculum did not affect seedling recruitment; yet, RAF did influence seedling performance, particularly resident RAF at treeline and in tundra, suggesting that mycorrhizal fungi are important to vegetation processes at the treeline-tundra ecotone.


Assuntos
Micorrizas/fisiologia , Árvores/microbiologia , Incêndios Florestais , Basidiomycota/fisiologia , Picea/crescimento & desenvolvimento , Picea/microbiologia , Raízes de Plantas/microbiologia , Populus/crescimento & desenvolvimento , Populus/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Especificidade da Espécie , Taiga , Árvores/crescimento & desenvolvimento , Tundra
7.
Int J Syst Evol Microbiol ; 70(7): 4358-4363, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32618556

RESUMO

A novel Gram-positive, aerobic and motile endophytic actinomycete, designated TRM 65233T, was isolated from the root of Peganum harmala L. collected from Xinjiang Uygur Autonomous Region of China. The isolate had white aerial mycelium and brown substrate mycelium on Gause's synthetic agar. Growth occurred at 10-40 °C, pH 6-9 with NaCl concentration of 0-6 % (w/v). Strain TRM 65233T contained meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The whole-cell hydrolysates included glucose and galactose as the major whole-cell sugars. The menaquinones were MK-9 (H4) and MK-7. The major cellular fatty acids were iso-C16 : 0, iso-C15 : 0 and anteiso-C17 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phospholipids, phosphatidylinositol and one unidentified lipid. Strain TRM 65233T showed the highest 16S rRNA gene sequence similarity to Actinokineospora cianjurensis BTCC B-558T (98.13 %), Actinokineospora auranticolor IFO 16518T (98.06 %), Actinokineospora spheciospongiae EG49T (97.99 %), Actinokineospora baliensis ID03-0561T (97.97 %), Actinokineospora mzabensis PAL84T (97.95 %) and Actinokineospora bangkokensis 44EHWT (97.06 %). The isolate was distinguished from these phylogenetically related strains by digital DNA-DNA hybridization and average nucleotide identity analyses and by a range of physiological and biochemical characteristics. The G+C content of the genomic DNA was 72.6 mol%. On the basis of polyphasic taxonomic data, strain TRM 65233T represents a novel species of the genus Actinokineospora, for which the name Actinokineospora pegani sp. nov. is proposed. The type strain is TRM 65233T (KCTC 49342=CCTCC AA 2019050).


Assuntos
Actinobacteria/classificação , Peganum/microbiologia , Filogenia , Raízes de Plantas/microbiologia , Actinobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
8.
Int J Syst Evol Microbiol ; 70(6): 3845-3851, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32501782

RESUMO

A novel endophytic actinomycete, designated strain p1410T, was isolated from the root of cattail pollen (Typha angustifolia L.) and characterized using a polyphasic approach. The strain had morphological characteristics and chemotaxonomic properties identical to those of members of the genus Nonomuraea. It produced spiral chains of spores on aerial mycelium as well as forming a pseudosporangium. Whole-cell hydrolysates contained meso-diaminopimelic acid, glucose, ribose and madurose. The menaquinones detected were MK-9(H2), MK-9(H4) and MK-9(H0). The major fatty acids were 10-methyl C17 : 0, iso-C16 : 0 and C17 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol mannoside and an unknown glycolipid. The DNA G+C content of the draft genome sequence, consisting of 11.4 Mbp, was 70.9 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain p1410T belongs to the genus Nonomuraea with the highest sequence similarity to Nonomuraea candida HMC10T (98.6 %), but phylogenetically clustered with Nonomuraea endophytica YIM 65601T (98.4 %) and Nonomuraea longicatena NRRL 15532T (98.3 %). Based on its phenotypic characteristics, DNA-DNA relatedness and average nucleotide identity, the strain is considered to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea typhae sp. nov. is proposed. The type strain is p1410T (=CCTCC AA 2019044T=JCM 33461T).


Assuntos
Actinobacteria/classificação , Filogenia , Raízes de Plantas/microbiologia , Typhaceae/microbiologia , Actinobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
9.
Arch Microbiol ; 202(8): 2169-2179, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32519022

RESUMO

Bacillus methylotrophicus has been demonstrated to promote growth of various plants, whereas the promoting effect of B. methylotrophicus on rice growth has been rarely reported. In this study, B. methylotrophicus DD-1, capable of efficiently promoting the growth of rice, was isolated from the root soil of rice plants. The isolate exhibited potassium-solubilizing (1.18 mg/L), Indole-3-acetic acid (IAA) (87.26 mg/L), Gibberellic acid (GA) (25.91 mg/L) and Siderophore production activity (52.32%). As indicated from the result, plant growth parameters (e.g., dry weight, tiller number, root and shoot length) of rice seedlings treated with the isolate DD-1 were more effective than those of the control group in pot and soilless culture experiments. Moreover, the adsorption capacity of rice roots which were soaked in the bacterial suspension of isolate increased with the increase in concentration and absorption time. In sterilized and unsterilized soil, conformation of root colonization activity by bacterial isolate established by its nearer existence to the rice root. Thus, the B. methylotrophicus DD-1 enhances plant growth promotion by multifarious growth promoting and root colonization traits, thereby augmenting potassium level in soil. Henceforth, the potential bacterium could be exploited for the development of biological fertilizer, leading towards sustainable agronomy.


Assuntos
Bacillus/fisiologia , Oryza/microbiologia , Raízes de Plantas/microbiologia , Plântula/microbiologia , Microbiologia do Solo , Bacillus/isolamento & purificação , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/crescimento & desenvolvimento , Desenvolvimento Vegetal , Plântula/crescimento & desenvolvimento , Sideróforos/metabolismo
10.
Arch Microbiol ; 202(8): 2279-2289, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32535790

RESUMO

Soils are rich in organics, particularly those that support the growth of plants. These organics are possible sources of sustainable energy, and a microbial fuel cell (MFC) system can potentially be used for this purpose. In this, the soil organic content expelled from plant root was possibly converted into electrical energy through the microbial metabolic process. The integration of MFC systems with living plant root system is a novel approach, which will facilitate sustainable resource for energy production. Therefore, the objective of this study is to electrochemically evaluate the paddy field MFCs (PF-MFCs) performance and methane emission under organic and conventional fertilization systems in paddy fields, and its impact on bacterial communities involved in bioelectricity production. Graphite (anode) and carbon (cathode) electrode MFC systems were configured and assembled in organic and conventionally fertilized paddy fields. The anode and bulk soil-associated bacterial communities were examined using high-throughput Illumina MiSeq sequencing platform. Our results revealed that the maximum electricity production and power density were observed in CFPF-MFC with less methane emission compared to OFPF-MFC. The next-generation sequencing (NGS) libraries showed that the bacterial population was significantly increased in the organic-fertilized field and the enhanced occurrence of the Geobacteraceae family in CFPF-MFC anode. By enhancing Geobacteraceae occurrence on the anode, the conventional fertilization improved the bioelectricity production with less methane emission. Further extension in the establishment of plant MFCs in various sedimentary environments will solve the global energy crisis.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Fertilizantes , Microbiologia do Solo , Carbono , Eletrodos/microbiologia , Raízes de Plantas/microbiologia , Solo/química
11.
Arch Microbiol ; 202(9): 2419-2428, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32591911

RESUMO

For sustainable agriculture in saline soil, extensive exploitation of salt-tolerant plant growth-promoting (PGP) bacteria and other symbiotic bacteria is required. This study was carried out to evaluate the efficiency of native salt-tolerant rice rhizobacteria for plant growth promotion under salt stress. A total of 188 bacteria were screened for assessing salt-tolerant capacity and nine isolates tolerating 12% NaCl (w/v) concentration were selected. Biochemical and molecular identification revealed that the salt-tolerant bacteria belonged to Bacillus sp, Exiguobacterium sp, Enterobacter sp, Lysinibacillus sp, Stenotrophomonas sp, Microbacterium sp, and Achromobacter sp. The increase in NaCl concentration from 2 to 4% decreases the PGP activities such as IAA production, P solubilization, K solubilization, and nitrate reduction. The effects of inoculation of salt-tolerant bacteria on the growth and different physiological properties of rice (Oryza sativa) were studied. It was found that the salinity affected the root and shoot length of the control plants; however, bacterial inoculant were found to effectively promote the growth of paddy under salinity stress. Further, bacterial inoculants substantially enhanced total chlorophyll, proline, total phenol, and oxidative damage such as electrolyte leakage and membrane stability index under salt stress. This study suggests that salt-tolerant PGP bacteria may be used for cultivation of O. sativa in salinized agricultural lands.


Assuntos
Fenômenos Fisiológicos Bacterianos , Oryza/microbiologia , Estresse Salino , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Clorofila/metabolismo , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Salinidade , Plantas Tolerantes a Sal/microbiologia , Solo/química , Simbiose/fisiologia
12.
Proc Natl Acad Sci U S A ; 117(28): 16649-16659, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32586957

RESUMO

Low availability of nitrogen (N) is often a major limiting factor to crop yield in most nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi are beneficial symbionts of most land plants that enhance plant nutrient uptake, particularly of phosphate. A growing number of reports point to the substantially increased N accumulation in many mycorrhizal plants; however, the contribution of AM symbiosis to plant N nutrition and the mechanisms underlying the AM-mediated N acquisition are still in the early stages of being understood. Here, we report that inoculation with AM fungus Rhizophagus irregularis remarkably promoted rice (Oryza sativa) growth and N acquisition, and about 42% of the overall N acquired by rice roots could be delivered via the symbiotic route under N-NO3 - supply condition. Mycorrhizal colonization strongly induced expression of the putative nitrate transporter gene OsNPF4.5 in rice roots, and its orthologs ZmNPF4.5 in Zea mays and SbNPF4.5 in Sorghum bicolor OsNPF4.5 is exclusively expressed in the cells containing arbuscules and displayed a low-affinity NO3 - transport activity when expressed in Xenopus laevis oocytes. Moreover, knockout of OsNPF4.5 resulted in a 45% decrease in symbiotic N uptake and a significant reduction in arbuscule incidence when NO3 - was supplied as an N source. Based on our results, we propose that the NPF4.5 plays a key role in mycorrhizal NO3 - acquisition, a symbiotic N uptake route that might be highly conserved in gramineous species.


Assuntos
Proteínas de Transporte de Ânions/metabolismo , Glomeromycota/fisiologia , Micorrizas/fisiologia , Nitrogênio/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Transporte de Ânions/genética , Regulação da Expressão Gênica de Plantas , Nitratos/metabolismo , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Sorghum/genética , Sorghum/metabolismo , Sorghum/microbiologia , Zea mays/genética , Zea mays/metabolismo , Zea mays/microbiologia
13.
Ecotoxicol Environ Saf ; 201: 110816, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32521370

RESUMO

Mine tailings contain dangerously high levels of toxic metals which pose a constant threat to local ecosystems. Few naturally grown native plants can colonize tailings site and the existence of their root-associated microbial populations is poorly understood. The objective of this study was to give further insights into the interactions between native plants and their microbiota during natural attenuation of abandoned V-Ti magnetite mine tailings. In the present work, we first examined the native plants' potential for phytoremediation using plant/soil analytical methods and then investigated the root microbial communities and their inferred functions using 16 S rRNA-based metagenomics. It was found that in V-Ti magnetite mine tailings the two dominant plants Bothriochloa ischaemum and Typha angustifolia were able to increase available nitrogen in the rhizosphere soil by 23.3% and 53.7% respectively. The translocation factors (TF) for both plants indicated that B. ischaemum was able to accumulate Pb (TF = 1.212), while T. angustifolia was an accumulator of Mn (TF = 2.502). The microbial community structure was more complex in the soil associated with T. angustifolia than with B. ischaemum. The presence of both plants significantly reduced the population of Acinetobacter. Specifically, B. ischaemum enriched Massilia, Opitutus and Hydrogenophaga species while T. angustifolia significantly increased rhizobia species. Multivariate analyses revealed that among all tested soil variables Fe and total organic carbon (TOC) could be the key factors in shaping the microbial structure. The putative functional analysis indicated that soil sample of B. ischaemum was abundant with nitrate/nitrite reduction-related functions while that of T. angustifolia was rich in nitrogen fixing functions. The results indicate that these native plants host a diverse range of soil microbes, whose community structure can be shaped by plant types and soil variables. It is also possible that these plants can be used to improve soil nitrogen content and serve as bioaccumulators for Pb or Mn for phytoremediation purposes.


Assuntos
Óxido Ferroso-Férrico/toxicidade , Microbiota/efeitos dos fármacos , Raízes de Plantas/microbiologia , Poluentes do Solo/toxicidade , Titânio/toxicidade , Vanádio/toxicidade , Biodegradação Ambiental , China , Óxido Ferroso-Férrico/análise , Metagenômica , Microbiota/genética , Mineração , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Rhizobium , Rizosfera , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Titânio/análise , Typhaceae/crescimento & desenvolvimento , Typhaceae/microbiologia , Vanádio/análise
14.
Int J Syst Evol Microbiol ; 70(7): 4171-4178, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32552985

RESUMO

A novel Gram-stain-negative strain, designated ZYY5T, was isolated from rice roots. Results of 16S rRNA gene analysis indicated that strain ZYY5T was a member of the genus Dickeya, with a highest similarity to Dickeya zeae DSM 18068T (98.5%). The major fatty acids were summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:0 and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c). Multi-locus sequence analysis using five concatenated genes (16S rRNA, atpD, infB, recA and gyrB) and phylogenomic analysis based on 2940 core gene sequences showed that strain ZYY5T formed a robust cluster with strains EC1, ZJU1202, DZ2Q, NCPPB 3531 and CSL RW192, while separated from the other strains of D. zeae. The orthologous average nucleotide identity (ANI) and digital DNA-DNAhybridization (dDDH) values among these six strains ranged from 96.8-99.9% and 73.7-99.8%, which supported that they were belonged to the same species. However, strain ZYY5T shared 58.4 of dDDH and 94.5% of ANI values with type strain D. zeae DSM 18068T, which were lower than the proposed species boundary cut-off for dDDH and ANI. The genomic analysis revealed that strain ZYY5T contained virulence-associated genes, which is same as the phylogenetic-related strains of the genus Dickeya. Based on the results of the polyphasic approaches, we propose that strain ZYY5T represents a novel species in the genus Dickeya, for which the name Dickeya oryzae sp. nov. (=JCM 33020 T=ACCC 61554 T) is proposed. Strains EC1, ZJU1202, DZ2Q, NCPPB 3531 and CSL RW192 should also be classified in the same genomospecies of D. oryzae same as ZYY5T.


Assuntos
Enterobacteriaceae/classificação , Oryza/microbiologia , Filogenia , Raízes de Plantas/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Enterobacteriaceae/isolamento & purificação , Ácidos Graxos/química , Genes Bacterianos , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
15.
Chemosphere ; 258: 127386, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32559495

RESUMO

Contamination of agricultural land with heavy metal is a serious biological and environmental issue. Such threat can be challenged by exploring the plant symbiotic microbes that can improve plant growth through phyto-hormones secretion and chromate chelation. In the current study, chromate resistant rhizospheric Staphylococcus arlettae strain MT4 was isolated from the rhizosphere of Malvestrum tricuspadatum L. The strain showed potential to secrete phytohormones and plant growth promoting secondary metabolites under induced chromate stress, making it a best suitable candidate in chromate stress alleviation. Moreover, the rhizobacterium MT4 significantly promoted the net assimilation and relative growth rate of sunflower grown in the presence of chromate (100 ppm). Chromate stress alleviation strategy of MT4 strain was three-fold. MT4 alleviated chromate stress and promoted the sunflower growth by suppressing the chromate intake by the host, modulating phytohormones and strengthening of the host's antioxidant system. The improved antioxidant system was confirmed by noticing lower ROS accumulation and improved ROS scavenging, lower peroxidase activity and higher accumulation of phenols and flavonoids.


Assuntos
Antioxidantes/metabolismo , Cromatos/toxicidade , Helianthus/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Rizosfera , Poluentes do Solo/toxicidade , Staphylococcus/crescimento & desenvolvimento , Biodegradação Ambiental , Cromatos/metabolismo , Helianthus/metabolismo , Helianthus/microbiologia , Oxirredução , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poluentes do Solo/metabolismo , Staphylococcus/metabolismo
16.
PLoS One ; 15(6): e0234537, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574172

RESUMO

Plant-soil feedback studies attempt to understand the interplay between composition of plant and soil microbial communities. A growing body of literature suggests that plant species can coexist when they interact with a subset of the soil microbial community that impacts plant performance. Most studies focus on the microbial community in the soil rhizosphere; therefore, the degree to which the bacterial community within plant roots (root-endophytic compartment) influences plant-microbe interactions remains relatively unknown. To determine if there is an interaction between conspecific vs heterospecific soil microbes and plant performance, we sequenced root-endophytic bacterial communities of five tallgrass-prairie plant species, each reciprocally grown with soil microbes from each hosts' soil rhizosphere. We found evidence of plant-soil feedbacks for some pairs of plant hosts; however, the strength and direction of feedbacks varied substantially across plant species pairs-from positive to negative feedbacks. Additionally, each plant species harbored a unique subset of root-endophytic bacteria. Conspecifics that hosted similar bacterial communities were more similar in biomass than individuals that hosted different bacterial communities, suggesting an important functional link between root-endophytic bacterial community composition and plant fitness. Our findings suggest a connection between an understudied component of the root-endophytic microbiome and plant performance, which may have important implications in understanding plant community composition and coexistence.


Assuntos
Microbiota/genética , Desenvolvimento Vegetal/genética , Plantas/microbiologia , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Endófitos/classificação , Endófitos/genética , Pradaria , Filogenia , Raízes de Plantas/genética , Raízes de Plantas/microbiologia , Plantas/genética , RNA Ribossômico 16S/genética , Rizosfera
17.
PLoS One ; 15(6): e0234546, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32589642

RESUMO

Perennial crops in agricultural systems can increase sustainability and the magnitude of ecosystem services, but yield may depend upon biotic context, including soil mutualists, pathogens and cropping diversity. These biotic factors themselves may interact with abiotic factors such as drought. We tested whether perennial crop yield depended on soil microbes, water availability and crop diversity by testing monocultures and mixtures of three perennial crop species: a novel perennial grain (intermediate wheatgrass-Thinopyrum intermedium-- that produces the perennial grain Kernza®), a potential perennial oilseed crop (Silphium intregrifolium), and alfalfa (Medicago sativa). Perennial crop performance depended upon both water regime and the presence of living soil, most likely the arbuscular mycorrhizal (AM) fungi in the whole soil inoculum from a long term perennial monoculture and from an undisturbed native remnant prairie. Specifically, both Silphium and alfalfa strongly benefited from AM fungi. The presence of native prairie AM fungi had a greater benefit to Silphium in dry pots and alfalfa in wet pots than AM fungi present in the perennial monoculture soil. Kernza did not benefit from AM fungi. Crop mixtures that included Kernza overyielded, but overyielding depended upon inoculation. Specifically, mixtures with Kernza overyielded most strongly in sterile soil as Kernza compensated for poor growth of Silphium and alfalfa. This study identifies the importance of soil biota and the context dependence of benefits of native microbes and the overyielding of mixtures in perennial crops.


Assuntos
Agricultura , Medicago sativa/fisiologia , Plantas Daninhas/crescimento & desenvolvimento , Estresse Fisiológico/fisiologia , Biota/fisiologia , Produtos Agrícolas/fisiologia , Ecossistema , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/microbiologia , Micorrizas/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Microbiologia do Solo , Simbiose/fisiologia
18.
Int J Food Microbiol ; 326: 108646, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32413802

RESUMO

The effects of using contaminated seed and water on the persistence and internalization of Salmonella Newport in organic spinach cultivars- Lazio, Space, Emilia and Waitiki were studied. Seeds were contaminated by either immersing in a suspension of Salmonella and then sprouted or were sprouted in Salmonella contaminated water in the dark at 25 °C. After 5 days, germinated sprouts were analyzed for S. Newport population and internalization. Germinated sprouts were potted in soil and grown in a plant incubator for 4 weeks. Leaves, stems and roots were sampled for Salmonella population by plating on CHROMagar™. Plants surface-sterilized with chlorine were analyzed for internalized pathogen. Potting soil and water runoff were sampled for Salmonella after 4 weeks of plant growth. Contaminated seeds and irrigation water had S. Newport populations of 7.64±0.43 log CFU/g and 7.12±0.04 log CFU/ml, respectively. Sprouts germinated using contaminated water or seeds had S. Newport populations of 8.09±0.04 and 8.08±0.03 log CFU/g, respectively and had a Salmonella population that was significantly higher than other spinach tissues (P<0.05). Populations of S. Newport in leaves, stem and roots of spinach plants were as follows: contaminated seed- 2.82±1.69, 1.69±0.86, and 4.41±0.62 log CFU/ml; contaminated water- 3.56±0.90, 3.04±0.31, and 4.03±0.42 log CFU/ml of macerated tissue suspension, respectively. Internalization was observed in plants developing from contaminated seeds and in sprouts germinated using contaminated water. S. Newport populations of 2.82±0.70 log CFU/g and 1.76±0.46 log CFU/ml were recovered from soil and water runoff, respectively. The results indicate that contamination of spinach during germination can result in persistence, internalization and environmental reintroduction of Salmonella.


Assuntos
Contaminação de Alimentos/análise , Folhas de Planta/microbiologia , Salmonella enterica/isolamento & purificação , Sementes/microbiologia , Spinacia oleracea/microbiologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Germinação , Raízes de Plantas/microbiologia , Sementes/crescimento & desenvolvimento , Microbiologia do Solo , Spinacia oleracea/crescimento & desenvolvimento
19.
Nat Commun ; 11(1): 2170, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358503

RESUMO

Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Citocininas/metabolismo , Resistência à Doença/genética , Ácidos Indolacéticos/metabolismo , Proteínas de Membrana/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/metabolismo , Transcriptoma/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Parede Celular/química , Parede Celular/metabolismo , Endossomos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Complexo de Golgi/metabolismo , Proteínas de Membrana/genética , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas/metabolismo , Plasmodioforídeos/patogenicidade , Via Secretória/genética , Solo , Proteínas de Transporte Vesicular/metabolismo
20.
Nat Commun ; 11(1): 2114, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32355217

RESUMO

Most plants associate with beneficial arbuscular mycorrhizal (AM) fungi that facilitate soil nutrient acquisition. Prior to contact, partner recognition triggers reciprocal genetic remodelling to enable colonisation. The plant Dwarf14-Like (D14L) receptor conditions pre-symbiotic perception of AM fungi, and also detects the smoke constituent karrikin. D14L-dependent signalling mechanisms, underpinning AM symbiosis are unknown. Here, we present the identification of a negative regulator from rice, which operates downstream of the D14L receptor, corresponding to the homologue of the Arabidopsis thaliana Suppressor of MAX2-1 (AtSMAX1) that functions in karrikin signalling. We demonstrate that rice SMAX1 is a suppressor of AM symbiosis, negatively regulating fungal colonisation and transcription of crucial signalling components and conserved symbiosis genes. Similarly, rice SMAX1 negatively controls strigolactone biosynthesis, demonstrating an unexpected crosstalk between the strigolactone and karrikin signalling pathways. We conclude that removal of SMAX1, resulting from D14L signalling activation, de-represses essential symbiotic programmes and increases strigolactone hormone production.


Assuntos
Proteínas de Arabidopsis/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Micorrizas/fisiologia , Oryza/microbiologia , Proteínas de Plantas/fisiologia , Simbiose , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Furanos/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Compostos Heterocíclicos com 3 Anéis/metabolismo , Homozigoto , Peptídeos e Proteínas de Sinalização Intracelular/genética , Lactonas/metabolismo , Família Multigênica , Oryza/genética , Filogenia , Proteínas de Plantas/genética , Raízes de Plantas/microbiologia , Piranos/metabolismo , RNA-Seq , Transdução de Sinais
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