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1.
Phytopathology ; 110(2): 297-308, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31483224

RESUMO

The reduction-oxidation (redox) environment of the phytobiome (i.e., the plant-microbe interface) can strongly influence the outcome of the interaction between microbial pathogens, commensals, and their host. We describe a noninvasive method using a bacterial bioreporter that responds to reactive oxygen species and redox-active chemicals to compare microenvironments perceived by microbes during their initial encounter of the plant surface. A redox-sensitive variant of green fluorescent protein (roGFP2), responsive to changes in intracellular levels of reduced and oxidized glutathione, was expressed under the constitutive SP6 and fruR promoters in the epiphytic bacterium Pantoea eucalypti 299R (Pe299R/roGFP2). Analyses of Pe299R/roGFP2 cells by ratiometric fluorometry showed concentration-dependent responses to several redox active chemicals, including hydrogen peroxide (H2O2), dithiothreitol (DTT), and menadione. Changes in intracellular redox were detected within 5 min of addition of the chemical to Pe299R/roGFP2 cells, with approximate detection limits of 25 and 6 µM for oxidation by H2O2 and menadione, respectively, and 10 µM for reduction by DTT. Caffeic acid, chlorogenic acid, and ascorbic acid mitigated the H2O2-induced oxidation of the roGFP2 bioreporter. Aqueous washes of peach and rose flower petals from young blossoms created a lower redox state in the roGFP2 bioreporter than washes from fully mature blossoms. The bioreporter also detected differences in surface washes from peach fruit at different stages of maturity and between wounded and nonwounded sites. The Pe299R/roGFP2 reporter rapidly assesses differences in redox microenvironments and provides a noninvasive tool that may complement traditional redox-sensitive chromophores and chemical analyses of cell extracts.


Assuntos
Técnicas Biossensoriais , Monitoramento Ambiental , Pantoea , Plantas , Técnicas Biossensoriais/métodos , Monitoramento Ambiental/métodos , Expressão Gênica/efeitos dos fármacos , Glutationa/farmacologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Peróxido de Hidrogênio/análise , Oxirredução , Pantoea/genética , Pantoea/metabolismo , Plantas/microbiologia , Espécies Reativas de Oxigênio/análise , Propriedades de Superfície , Vitamina K 3/análise
2.
Arch Microbiol ; 202(1): 1-16, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31552478

RESUMO

The acerbic elevation of toxic metal ions in arable lands, enhance the risk of their accumulation and biomagnification in crops as well as in humans. Phytoremediation is an eco-friendly approach to clear metal-contaminated lands by making use of metal accumulation potential of plants; which are referred to as hyperaccumulators. This phytoremediation potential can be enhanced with the symbiotic association between the root of hyperaccumulators and arbuscular mycorrhizae. Modification of root morphology, enhancement of antioxidants biosynthesis, and the increase in shoot biomass are the changes observed in plants as a result of indirect influence of arbuscular mycorrhizae. Direct influence of arbuscular mycorrhizae on enhancing metal tolerance of plants includes immobilization strategies, adsorption of metals on to the hyphal wall and glomalin exudation. Furthermore, we have discussed arbuscular mycorrhizal induced increment in the metal tolerance potential of plants through the alteration in various metabolic processes with special emphasis to the phenylpropanoid pathway.


Assuntos
Biodegradação Ambiental , Metais/toxicidade , Micorrizas/metabolismo , Raízes de Plantas/microbiologia , Plantas/efeitos dos fármacos , Plantas/microbiologia , Simbiose/fisiologia , Biomassa , Poluentes do Solo/toxicidade
3.
Phytomedicine ; 64: 153081, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31568956

RESUMO

BACKGROUND: Human tumors are still a major threat to human health and plant tumors negatively affect agricultural yields. Both areas of research are developing largely independent of each other. Treatment of both plant and human tumors remains unsatisfactory and novel therapy options are urgently needed. HYPOTHESIS: The concept of this paper is to compare cellular and molecular mechanisms of tumor development in plants and human beings and to explore possibilities to develop novel treatment strategies based on bioactive secondary plant metabolites. The interdisciplinary discourse may unravel commonalities and differences in the biology of plant and human tumors as basis for rational drug development. RESULTS: Plant tumors and galls develop upon infection by bacteria (e.g. Agrobacterium tumefaciens and A. vitis, which harbor oncogenic T-DNA) and by insects (e.g. gall wasps, aphids). Plant tumors are benign, i.e. they usually do not ultimately kill their host, but they can lead to considerable economic damage due to reduced crop yields of cultivated plants. Human tumors develop by biological carcinogenesis (i.e. viruses and other infectious agents), chemical carcinogenesis (anthropogenic and non-anthropogenic environmental toxic xenobiotics) and physical carcinogenesis (radioactivity, UV-radiation). The majority of human tumors are malignant with lethal outcome. Although treatments for both plant and human tumors are available (antibiotics and apathogenic bacterial strains for plant tumors, cytostatic drugs for human tumors), treatment successes are non-satisfactory, because of drug resistance and the severe adverse side effects. In human beings, attacks by microbes are repelled by cellular immunity (i.e. innate and acquired immune systems). Plants instead display chemical defense mechanisms, whereby constitutively expressed phytoanticipin compounds compare to the innate human immune system, the acquired human immune system compares to phytoalexins, which are induced by appropriate biotic or abiotic stressors. Some chemical weapons of this armory of secondary metabolites are also active against plant galls. There is a mutual co-evolution between plant defense and animals/human beings, which was sometimes referred to as animal plant warfare. As a consequence, hepatic phase I-III metabolization and excretion developed in animals and human beings to detoxify harmful phytochemicals. On the other hand, plants invented "pro-drugs" during evolution, which are activated and toxified in animals by this hepatic biotransformation system. Recent efforts focus on phytochemicals that specifically target tumor-related mechanisms and proteins, e.g. angiogenic or metastatic inhibitors, stimulators of the immune system to improve anti-tumor immunity, specific cell death or cancer stem cell inhibitors, inhibitors of DNA damage and epigenomic deregulation, specific inhibitors of driver genes of carcinogenesis (e.g. oncogenes), inhibitors of multidrug resistance (i.e. ABC transporter efflux inhibitors), secondary metabolites against plant tumors. CONCLUSION: The exploitation of bioactive secondary metabolites to treat plant or human tumors bears a tremendous therapeutic potential. Although there are fundamental differences between human and plant tumors, either isolated phytochemicals and their (semi)synthetic derivatives or chemically defined and standardized plant extracts may offer new therapy options to decrease human tumor incidence and mortality as well as to increase agricultural yields by fighting crown galls.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias/etiologia , Doenças das Plantas/etiologia , Fenômenos Fisiológicos Vegetais , Plantas/metabolismo , Agrobacterium tumefaciens/patogenicidade , Animais , Antibióticos Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Humanos , Neoplasias/tratamento farmacológico , Compostos Fitoquímicos , Imunidade Vegetal , Plantas/microbiologia , Metabolismo Secundário
4.
Int J Mol Sci ; 20(20)2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615004

RESUMO

Plant pathogens secrete proteins called effectors into the cells of their host to modulate the host immune response against colonization. Effectors can either modify or arrest host target proteins to sabotage the signaling pathway, and therefore are considered potential drug targets for crop disease control. In earlier research, the Xanthomonas type III effector XopAI was predicted to be a member of the arginine-specific mono-ADP-ribosyltransferase family. However, the crystal structure of XopAI revealed an altered active site that is unsuitable to bind the cofactor NAD+, but with the capability to capture an arginine-containing peptide from XopAI itself. The arginine peptide consists of residues 60 through 69 of XopAI, and residue 62 (R62) is key to determining the protein-peptide interaction. The crystal structure and the molecular dynamics simulation results indicate that specific arginine recognition is mediated by hydrogen bonds provided by the backbone oxygen atoms from residues W154, T155, and T156, and a salt bridge provided by the E265 sidechain. In addition, a protruding loop of XopAI adopts dynamic conformations in response to arginine peptide binding and is probably involved in target protein recognition. These data suggest that XopAI binds to its target protein by the peptide-binding ability, and therefore, it promotes disease progression. Our findings reveal an unexpected and intriguing function of XopAI and pave the way for further investigation on the role of XopAI in pathogen invasion.


Assuntos
ADP Ribose Transferases/química , Arginina/química , Peptídeos/química , Xanthomonas/química , ADP Ribose Transferases/genética , Sequência de Aminoácidos/genética , Arginina/genética , Domínio Catalítico/genética , Cristalografia por Raios X , Simulação de Dinâmica Molecular , Oxigênio/química , Peptídeos/genética , Plantas/genética , Plantas/microbiologia , Ligação Proteica , Conformação Proteica , Transdução de Sinais/genética , Xanthomonas/enzimologia , Xanthomonas/patogenicidade
5.
Plant Mol Biol ; 101(4-5): 343-354, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31621005

RESUMO

KEY MESSAGE: Short review focussing on the role and targeting of vacuolar substructure in plant immunity and pathogenesis. Plants lack specialized immune cells, therefore each plant cell must defend itself against invading pathogens. A typical plant defense strategy is the hypersensitive response that results in host cell death at the site of infection, a process largely regulated by the vacuole. In plant cells, the vacuole is a vital organelle that plays a central role in numerous fundamental processes, such as development, reproduction, and cellular responses to biotic and abiotic stimuli. It shows divergent membranous structures that are continuously transforming. Recent technical advances in visualization and live-cell imaging have significantly altered our view of the vacuolar structures and their dynamics. Understanding the active nature of the vacuolar structures and the mechanisms of vacuole-mediated defense responses is of great importance in understanding plant-pathogen interactions. In this review, we present an overview of the current knowledge about the vacuole and its internal structures, as well as their role in plant-microbe interactions. There is so far limited information on the modulation of the vacuolar structures by pathogens, but recent research has identified the vacuole as a possible target of microbial interference.


Assuntos
Interações Hospedeiro-Patógeno , Imunidade Vegetal , Plantas/ultraestrutura , Vacúolos/ultraestrutura , Biomarcadores/metabolismo , Morte Celular , Membranas Intracelulares/imunologia , Membranas Intracelulares/microbiologia , Membranas Intracelulares/ultraestrutura , Proteínas de Plantas/metabolismo , Plantas/imunologia , Plantas/microbiologia , Vacúolos/imunologia , Vacúolos/microbiologia
6.
Int J Mol Sci ; 20(19)2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31623351

RESUMO

The genus Flavobacterium contains a large group of commensal bacteria identified in diverse terrestrial and aquatic habitats. We compared the genome of a new species Flavobacterium akiainvivens IK-1T to public available genomes of Flavobacterium species to reveal the genomic traits and ecological roles of IK-1T. Principle component analysis (PCA) of carbohydrate-active enzyme classes suggests that IK-1T belongs to a terrestrial clade of Flavobacterium. In addition, type 2 and type 9 secretion systems involved in bacteria-environment interactions were identified in the IK-1T genome. The IK-1T genome encodes eukaryotic-like domain containing proteins including ankyrin repeats, von Willebrand factor type A domain, and major royal jelly proteins, suggesting that IK-1T may alter plant host physiology by secreting eukaryotic-like proteins that mimic host proteins. A novel two-component system FaRpfC-FaYpdB was identified in the IK-1T genome, which may mediate quorum sensing to regulate global gene expressions. Our findings suggest that comparative genome analyses of Flavobacterium spp. reveal that IK-1T has adapted to a terrestrial niche. Further functional characterizations of IK-1T secreted proteins and their regulation systems will shed light on molecular basis of bacteria-plant interactions in environments.


Assuntos
Adaptação Fisiológica , Flavobacterium/fisiologia , Genoma Bacteriano , Genômica , Interações Hospedeiro-Patógeno , Plantas/microbiologia , Fenômenos Fisiológicos Bacterianos , Evolução Biológica , Biologia Computacional/métodos , Flavobacterium/classificação , Genômica/métodos , Doenças das Plantas/microbiologia , Percepção de Quorum , Sintenia
7.
Bioengineered ; 10(1): 409-424, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31502497

RESUMO

There is increasing difficulty in identifying new plant leaf diseases as a result of environmental change. There is a need to identify the factors influencing the emergence and the increasing incidences of these diseases. Here, we present emerging fungal plant leaf diseases and describe their environmental speciation. We considered the factors controlling for local adaptation associated with environmental speciation. We determined that the advent of emergent fungal leaf diseases is closely connected to environmental speciation. Fungal pathogens targeting the leaves may adversely affect the entire plant body. To mitigate the injury caused by these pathogens, it is necessary to be able to detect and identify them early in the infection process. In this way, their distribution, virulence, incidence, and severity could be attenuated.


Assuntos
Fungos/classificação , Especiação Genética , Interações Hospedeiro-Patógeno/genética , Doenças das Plantas/classificação , Plantas/microbiologia , Fungos/efeitos dos fármacos , Fungos/genética , Fungos/patogenicidade , Fungicidas Industriais/farmacologia , Umidade , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Temperatura Ambiente , Virulência
8.
Molecules ; 24(17)2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31470567

RESUMO

BACKGROUND: The development of new antifungal agents has always been a hot research topic in pesticide development. In this study, a series of derivatives of natural compound ß-pinene were prepared, and the antifungal activities of these derivatives were evaluated. The purpose of this work is to develop some novel molecules as promising new fungicides. METHODS: Through a variety of chemical reactions, ß-pinene was transformed into a series of ß-pinene-based derivatives containing amide moieties and acylthiourea moieties. The antifungal activities of these derivatives against five plant pathogens including Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria kikuchiana, Phomopsis sp. and Phytophthora capsici were tested; preliminary structure-activity relationship was discussed. RESULTS: Some derivatives exhibited moderate or significant antifungal activity due to the fusion of the amide moiety or the acylthiourea moiety with the pinane skeleton. The structure-activity relationship analysis showed that the fluorine atom and the strong electron withdrawing nitro group, or trifluoromethyl group on the benzene ring of the derivatives had a significant effect on the improvement of the antifungal activity against Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria kikuchiana and Phomopsis sp. Meanwhile, the introduction of an ethyl group at the meta-position on the benzene ring of the derivatives could improve the antifungal activity against Phytophthora capsici. Compounds 4e, 4h, 4q, 4r exhibited broad-spectrum antifungal activity against the tested strains. Compound 4o had significant antifungal activity against Phytophthora capsici (IC50 = 0.18 µmol/L). These derivatives were expected to be used as precursor molecules for novel pesticide development in further research.


Assuntos
Alternaria/efeitos dos fármacos , Colletotrichum/efeitos dos fármacos , Fungicidas Industriais/síntese química , Fusarium/efeitos dos fármacos , Phytophthora/efeitos dos fármacos , Sordariales/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Amidas/química , Colletotrichum/crescimento & desenvolvimento , Fungicidas Industriais/farmacologia , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Phytophthora/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , Plantas/microbiologia , Sordariales/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tioureia/química
9.
Nat Commun ; 10(1): 3982, 2019 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-31484931

RESUMO

Boreal forests are ecosystems with low nitrogen (N) availability that store globally significant amounts of carbon (C), mainly in plant biomass and soil organic matter (SOM). Although crucial for future climate change predictions, the mechanisms controlling boreal C and N pools are not well understood. Here, using a three-year field experiment, we compare SOM decomposition and stabilization in the presence of roots, with exclusion of roots but presence of fungal hyphae and with exclusion of both roots and fungal hyphae. Roots accelerate SOM decomposition compared to the root exclusion treatments, but also promote a different soil N economy with higher concentrations of organic soil N compared to inorganic soil N accompanied with the build-up of stable SOM-N. In contrast, root exclusion leads to an inorganic soil N economy (i.e., high level of inorganic N) with reduced stable SOM-N build-up. Based on our findings, we provide a framework on how plant roots affect SOM decomposition and stabilization.


Assuntos
Ecossistema , Compostos Orgânicos/metabolismo , Raízes de Plantas/metabolismo , Solo/química , Taiga , Biomassa , Carbono/metabolismo , Hifas/fisiologia , Modelos Biológicos , Nitrogênio/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Plantas/metabolismo , Plantas/microbiologia , Microbiologia do Solo
10.
Appl Microbiol Biotechnol ; 103(18): 7385-7397, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31375881

RESUMO

Climate change is a crucial issue among the serious emerging problems which got a global attention in the last few decades. With the climate change, worldwide crop production has been seriously affected by drought stress. In this regard, various technologies including traditional breeding and genetic engineering are used to cope with drought stress. However, the interactions between plants and endophytic bacteria emerged as an interesting era of knowledge that can be used for novel agriculture practices. Endophytic bacteria which survive within plant tissues are among the most appropriate technologies improving plant growth and yield under drought conditions. These endophytic bacteria live within plant tissues and release various phytochemicals that assist plant to withstand in harsh environmental conditions, i.e., drought stress. Their plant growth-promoting characteristics include nitrogen fixation, phosphate solubilization, mineral uptake, and the production of siderophore, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and various phytohormones. These plant growth promoting characteristics of endophytic bacteria improve root length and density, which lead to the enhance drought tolerance. In addition, plant-endophytic bacteria assist plant to withstand against drought stress by producing drought-tolerant substances, for instance, abscisic acid, indole-3-acetic acid, ACC deaminase, and various volatile compounds. Indirectly, endophytic bacteria also improve osmotic adjustment, relative water content, and antioxidant activity of inoculated plants. Altogether, these bacterial-mediated drought tolerance and plant growth-promoting processes continue even under severe drought conditions which lead to enhanced plant growth promotion and yield. The present review highlights a natural and environment-friendly strategy in the form of drought-tolerant and plant growth-promoting endophytic bacteria to improve drought tolerance in plants.


Assuntos
Fenômenos Fisiológicos Bacterianos , Secas , Endófitos/fisiologia , Plantas/microbiologia , Estresse Fisiológico , Agricultura , Interações entre Hospedeiro e Microrganismos , Fenômenos Fisiológicos Vegetais , Raízes de Plantas/microbiologia , Rizosfera , Sideróforos
11.
Cell Host Microbe ; 26(2): 183-192, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31415751

RESUMO

In the past four decades, tremendous progress has been made in understanding how plants respond to microbial colonization and how microbial pathogens and symbionts reprogram plant cellular processes. In contrast, our knowledge of how environmental conditions impact plant-microbe interactions is less understood at the mechanistic level, as most molecular studies are performed under simple and static laboratory conditions. In this review, we highlight research that begins to shed light on the mechanisms by which environmental conditions influence diverse plant-pathogen, plant-symbiont, and plant-microbiota interactions. There is a great need to increase efforts in this important area of research in order to reach a systems-level understanding of plant-microbe interactions that are more reflective of what occurs in nature.


Assuntos
Meio Ambiente , Interações entre Hospedeiro e Microrganismos/fisiologia , Microbiota/fisiologia , Fenômenos Fisiológicos Vegetais , Plantas/microbiologia , Relógios Circadianos , Mudança Climática , Secas , Umidade , Imunidade Inata , Luz , Doenças das Plantas/imunologia , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Plantas/imunologia , Solo/química , Microbiologia do Solo , Estresse Fisiológico , Simbiose , Temperatura Ambiente
12.
J Basic Microbiol ; 59(10): 992-1003, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31410872

RESUMO

Revegetation accelerates the recovery of degraded lands. Different microbial trophic groups underpin this acceleration from the aspects of soil structure stabilization, nutrient accumulation, and ecosystem functions. However, little is known about how revegetation influences the community and biodiversity of different soil microbial trophic groups. Here, six revegetation treatments with different plantings of plant species were established at an excavation pit in the Qinghai-Tibetan Plateau. Communities of plant, bacteria, and several key soil fungal groups were investigated after 12 years of revegetation. Plant and all microbial trophic group compositions were markedly influenced by revegetation treatments. Total fungal and pathogenic fungal compositions were not significantly predicted by any factor of plant and soil, but arbuscular mycorrhizal fungal composition could be mainly predicted by plant composition and plant P content. Bacterial composition was mainly determined by soil total N, organic carbon concentration, and moisture content; and saprotrophic fungal composition was mainly determined by soil organic carbon. Soil pH was the strongest factor to predict bacterial metabolic functions. Our findings highlight that even the differences of microbial compositions were because of different revegetation treatments, but each trophic microbial composition had different relations with plant and/or soil; especially, the bacterial community and metabolic functions and saprotrophic fungal community were more correlated with soil properties rather than plant community or characteristics per se.


Assuntos
Recuperação e Remediação Ambiental , Pradaria , Plantas/classificação , Microbiologia do Solo , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/análise , Carbono/metabolismo , Fungos/classificação , Fungos/isolamento & purificação , Fungos/metabolismo , Micorrizas/classificação , Micorrizas/isolamento & purificação , Micorrizas/metabolismo , Nitrogênio/análise , Nitrogênio/metabolismo , Fosfatos/análise , Fosfatos/metabolismo , Plantas/química , Plantas/metabolismo , Plantas/microbiologia , Solo/química , Tibet
13.
Can J Microbiol ; 65(12): 880-894, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31442382

RESUMO

The present study focused on the characterization of 10 Curtobacterium citreum strains isolated from the rhizosphere of pioneer plants growing on ultramafic soils from New Caledonia. Taxonomic status was investigated using a polyphasic approach. Three strains (BE, BB, and AM) were selected in terms of multiple-metal resistance and plant-growth-promoting traits. They were tested on sorghum growing on ultramafic soil and compared with the reference strain C. citreum DSM20528T. To better understand the bacterial mechanisms involved, biosorption, bioaccumulation, and biofilm formation were investigated for the representative strain of the ultramafic cluster (strain BE) versus C. citreum DSM20528T. The polyphasic approach confirmed that all native isolates belong to the same cluster and are C. citreum. The inoculation of sorghum with strains BE and BB significantly reduced Ni content in shoots compared with inoculation with C. citreum DSM20528T and control values. This result was related to the higher Ni tolerance of the ultramafic strains compared with C. citreum DSM20528T. Ni biosorption and bioaccumulation showed that BE exhibited a lower Ni content, which is explained by the ability of this strain to produce exopolysaccharides involved in Ni chelation. We suggested that ultramafic C. citreum strains are more adapted to this substrate than is C. citreum DSM20528T, and their features allow them to enhance plant metal tolerance.


Assuntos
Actinomycetales/fisiologia , Fenômenos Fisiológicos Vegetais , Plantas/microbiologia , Microbiologia do Solo , Solo/química , Actinomycetales/classificação , Actinomycetales/genética , Actinomycetales/metabolismo , Metais/análise , Metais/metabolismo , Nova Caledônia , Plantas/metabolismo , Polissacarídeos Bacterianos/metabolismo , Rizosfera , Sorghum/metabolismo , Sorghum/microbiologia , Sorghum/fisiologia
14.
Microbiol Res ; 227: 126292, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421719

RESUMO

Azotobacter chroococcum (Az) and Trichoderma viride (Tv) represent agriculturally important and beneficial plant growth promoting options which contribute towards nutrient management and biocontrol, respectively. When Az and Tv are co-cultured, they form a biofilm, which has proved promising as an inoculant in several crops; however, the basic aspects related to regulation of biofilm formation were not investigated. Therefore, whole transcriptome sequencing (Illumina NextSeq500) and gene expression analyses were undertaken, related to biofilm formation vis a vis Tv and Az growing individually. Significant changes in the transcriptome profiles of biofilm were recorded and validated through qPCR analyses. In-depth evaluation also identified several genes (phoA, phoB, glgP, alg8, sipW, purB, pssA, fadD) specifically involved in biofilm formation in Az, Tv and Tv-Az. Genes coding for RNA-dependent RNA polymerase, ABC transporters, translation elongation factor EF-1, molecular chaperones and double homeobox 4 were either up-regulated or down-regulated during biofilm formation. To our knowledge, this is the first report on the modulation of gene expression in an agriculturally beneficial association, as a biofilm. Our results provide insights into the regulatory factors involved during biofilm formation, which can help to improve the beneficial effects and develop more effective and promising plant- microbe associations.


Assuntos
Azotobacter/genética , Biofilmes/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Interações Microbianas/genética , Transcriptoma , Trichoderma/genética , Técnicas de Cocultura , Regulação para Baixo , Regulação Bacteriana da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Genes Bacterianos/genética , Genes Fúngicos/genética , Interações Microbianas/fisiologia , Desenvolvimento Vegetal , Plantas/microbiologia , Regulação para Cima
15.
Syst Appl Microbiol ; 42(5): 126004, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31402073

RESUMO

Two novel strains, designated 11W25H-1T and 8H24J-4-2T, were isolated from surface-sterilized plant tissues collected from the Taklamakan Desert in the Xinjiang Uygur Autonomous Region, China. The strains were characterized by a polyphasic approach in order to clarify their taxonomic positions. They were Gram-stain positive, aerobic, non-motile, non-spore-forming and rod-shaped. The 16S rRNA gene sequences of the strains showed highest similarities with Labedella gwakjiensis KCTC 19176T (99.2% and 98.9%, respectively) and Labedella endophytica CPCC 203961T (98.9% and 99.0%, respectively). The sequence similarity between strains 11W25H-1T and 8H24J-4-2T was 99.4%. Phylogenetic analyses based on 16S rRNA gene sequences and single-copy phylogenetic marker genes (pMGs) showed that the two strains belonged to the genus Labedella and formed a separate cluster from the closest species L. gwakjiensis KCTC 19176T and L. endophytica CPCC 203961T. Genomic analyses, including average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), clearly separated the strains from each other and from the other species of the genus Labedella with values below the thresholds for species delineation. The two strains showed chemotaxonomic characteristics and phenotypic properties in agreement with the description of the genus Labedella and also confirmed the differentiation from the closest species. The data demonstrated that strains 11W25H-1T and 8H24J-4-2T represented two novel species of the genus Labedella, for which the names Labedella phragmitis sp. nov. (type strain 11W25H-1T=JCM 33144T=CGMCC 1.16700T) and Labedella populi sp. nov. (type strain 8H24J-4-2T=JCM 33143T=CGMCC 1.16697T) are proposed.


Assuntos
Actinobacteria/classificação , Filogenia , Plantas/microbiologia , Actinobacteria/química , Actinobacteria/genética , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos/genética , Genoma Bacteriano/genética , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie , Vitamina K 2/química
16.
Chem Biodivers ; 16(10): e1900398, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31456316

RESUMO

Phytotoxic natural products with either unique or various structures are one of the most abundant sources for the discovery of potential allelochemicals, natural herbicides, and plant growth regulators. Phytotoxic diterpenoids, a relatively large class of natural products, play an important role in the plant-plant or plant-microorganism interactions. This article argues that the phytotoxic diterpenoids isolated from the plants and microorganisms can either inhibit the seed germination and the growth of plant seedlings or lead to some disease symptoms on the tested plant tissues and plant seedlings.


Assuntos
Produtos Biológicos/farmacologia , Diterpenos/farmacologia , Compostos Fitoquímicos/farmacologia , Plantas/química , Plântula/efeitos dos fármacos , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Diterpenos/química , Diterpenos/isolamento & purificação , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Plantas/efeitos dos fármacos , Plantas/microbiologia
17.
Biosci Biotechnol Biochem ; 83(11): 2163-2171, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31272289

RESUMO

Motile bacteria often exhibit chemotaxis toward favorable compounds. However, the diversity of bacteria that are attracted to a given substance is largely unknown. This study aimed to reveal the diversity of bacteria with natural chemotaxis towards methanol. We tried to enrich environmental chemotactic bacteria using a glass capillary that is half-filled with methanol solidified with agarose as a trap ("chemotaxis fishing"). The pilot experiment using methanol-chemotactic Methylobacterium aquaticum strain 22A enriched the cells by 46-fold. The method was then applied to bacterial suspensions from paddy water and plants. Depending on the isolation sources and the methods of motility induction, methylotrophic bacteria were enriched 1.2-330-fold. The fished isolates belong to 32 species in 18 genera, mainly containing Acinetobacter, Methylobacterium and Pseudomonas species. Our chemotaxis fishing unveiled a part of diversity of the bacteria with natural chemotaxis towards methanol.


Assuntos
Bactérias/citologia , Bactérias/efeitos dos fármacos , Quimiotaxia/efeitos dos fármacos , Metanol/farmacologia , Técnicas Microbiológicas/métodos , Plantas/microbiologia
19.
Chemosphere ; 235: 248-259, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31260865

RESUMO

Elucidating the mechanisms underpinning the responses of abundant and rare microbial taxa to environmental disturbances is essential for understanding the biodiversity-stability relationship and maintaining microbial diversity. Here, we explored the response patterns of abundant and rare bacterial taxa to disturbances by invasive plant growth and oil contamination in agricultural soils across a large spatial scale (latitude gradient = 18.62°-46.51°). Our meta-analysis based on existing Illumina sequencing datasets showed that abundant taxa persisted under the disturbances whereas rare taxa were more easily affected, indicating the higher resilience or resistance of abundant taxa to disturbances. The responses of abundant taxa were associated with mean annual temperature at the sampling sites, while rare taxa instead showed stochastic responses. There were significantly negative linear regressions between bacterial α-diversity and community dissimilarities (disturbed vs. undisturbed soils), suggesting stronger resilience or resistance in those bacterial communities with higher α-diversity. This resilience or resistance was mainly associated with the α-diversity of abundant taxa. Our network analysis showed that the disturbances substantially decreased the strength of the connections, loosened the co-occurrence relationships, and reshaped the complex bacterial interactions. In the undisturbed soils, abundant taxa were located in central positions within the network more often than were rare taxa, while these trends were reversed in the disturbed soils. Our results suggest that abundant taxa play a dominant role in the stability and maintenance of agro-soil bacterial communities, while rare taxa could greatly influence local bacterial interactions under environmental disturbances.


Assuntos
Bactérias/classificação , Biodiversidade , Microbiota , Plantas/microbiologia , Microbiologia do Solo , Solo/química , Bactérias/genética , DNA Bacteriano/genética
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