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1.
An Acad Bras Cienc ; 91(3): e20181295, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432907

RESUMO

The banana tree is associated with different species of endophytic bacteria that can stimulate plant growth. However, further studies are needed to better understand the relationships between this group of bacteria and the host plant. The objective of this study was to investigate the localization of the EB-40 (Bacillus sp.) through anatomical and ultrastructural analyses in micropropagated banana plantlets. The results demonstrated the effective colonization of the EB-40 isolate in the intercellular and intracellular spaces, as well as in the rhizosphere region. The wall of endophytic bacteria contains calcium and nitrogen. The EB-40 isolate was also observed to associate with the plasma membrane and cell wall. These results further our understanding of the mechanisms involved in the colonization of plant cells by endophytic bacteria in micropropagated banana plantlets.


Assuntos
Bacillus/fisiologia , Endófitos/ultraestrutura , Musa/microbiologia , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Bacillus/ultraestrutura , Microscopia Eletrônica de Varredura , Musa/crescimento & desenvolvimento , Musa/ultraestrutura , Raízes de Plantas/crescimento & desenvolvimento
2.
Microbiol Res ; 227: 126310, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421714

RESUMO

Deployment of plant endophytes at field level is reported to make an impact on agricultural crop productivity; development and deployment of suitable crop specific plant probiotics in a suitable delivery matrix is a value-added task. In our study, we attempted to develop bioformulations of native, fungal endophytes of Coleus forskohlii to improve plant yield using two different carrier-based materials (talc and wheat bran). Initially, fungal endophytes (RF1, SF1, and SF2) were grown on sterilized wheat bran under solid state condition and their growth kinetics and pattern were analyzed by ergosterol content and scanning electron microscope, respectively. 10-day-grown fungal endophytic cultures were used for the development of two types of formulations (wheat bran and talc-based formulations) and tested for their efficacy on host plant, C. forskohlii under field conditions. Interestingly, application of wheat bran-based endophytic formulations significantly (p < 0.01) enhanced plant height (12-29%), number of branches (51-63%), root biomass (26-33%), photosynthetic pigments (32-101%), and forskolin content (35-56%) compared to talc-based formulations under field conditions. Shelf life of endophytes (RF1, SF1, and SF2) in both formulations revealed spore viability in wheat bran-based formulations for 6 months storage period as compared to talc-based formulations. Overall, the present investigation envisages developing plant probiotic bioformulations of functional endophytes of C. forskohlii to enhance root biomass and in planta forskolin content.


Assuntos
Endófitos/crescimento & desenvolvimento , Endófitos/fisiologia , Desenvolvimento Vegetal , Plectranthus/microbiologia , Probióticos , Biomassa , Colforsina/metabolismo , Produtos Agrícolas , Fibras na Dieta/microbiologia , Ergosterol/metabolismo , Viabilidade Microbiana , Fotossíntese , Pigmentos Biológicos , Raízes de Plantas/microbiologia , Probióticos/economia
3.
Plant Mol Biol ; 101(3): 315-323, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392474

RESUMO

KEY MESSAGE: Pre-treatment of soybean seedlings with 200 µM salicylic acid before fungal inoculation significantly alleviated disease resistance in soybean seedlings against Fusarium solani infection. Sudden death syndrome of soybean is largely caused by Fusarium solani (F. solani). Salicylic acid (SA) has been reported to induce resistance in plants against many pathogens. However, the effect of exogenous SA application on F. solani infection of soybean is less reported. This study investigated the effect of foliar application of SA on soybean seedlings before F. solani infection. Seedlings were sprayed with 200 µM SA and inoculated with F. solani after 24 h of last SA application. After 3 days post-inoculation, seedlings treated with 200 µM SA showed significantly fewer disease symptoms with increased endogenous SA level, SA marker genes expression and antioxidant activities in the SA-treated seedlings more than the untreated control seedlings. Furthermore, the decrease in hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels was observed in the SA-treated plants as compared to the untreated plants. Analysis of the effect of SA application on F. solani showed that the mycelia growth of F. solani was not affected by SA treatment. Further investigation in this study revealed a decreased in F. solani biomass content in the SA treated seedlings. Results from the present study show that pre-treatment of 200 µM SA can induce resistance of soybean seedlings against F. solani infection.


Assuntos
Resistência à Doença/efeitos dos fármacos , Fusarium/patogenicidade , Doenças das Plantas/microbiologia , Ácido Salicílico/farmacologia , Soja/microbiologia , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/microbiologia , Plântula/efeitos dos fármacos , Plântula/microbiologia , Soja/efeitos dos fármacos
4.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2767-2774, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418202

RESUMO

To reveal the physiological effects of rice alleviated by cadmium-tolerant Pseudomonas aeruginosa under cadmium stress condition, the influences of bacterial strian on the root vigor and leaf physiological characteristics were analyzed under a set of hydroponic experiments involving adding bacteria suspension, empty carrier, microbial inoculum with 20 µmol·L-1 Cd. Cadmium-free treatment as control. The results showed that the root vigor was significantly inhibited, leaf photosynthetic rate decreased, and the contents of soluble protein, flavonoid and total phenols in rice leaves were reduced, while the contents of malondialdehyde (MDA) and superoxide anion(O2-·) increased significantly under cadmium stress condition. Compared with cadmium treatment, root vigors of rice were increased by 36.1%-42.5% and 49.4%-53.0% respectively in bacteria suspension and microbial inoculum additions, net photosynthetic rates in leaves were increased by 118.5%-147.1% and 137.6%-156.9%, and the contents of soluble protein were increased by 37.0%-49.3% and 37.7%-72.6%, respectively. For the bacteria suspension treatment, the activities of SOD, POD and CAT in leaves were increased by 25.8%-36.6%, 40.9%-55.9%, 24.0%-29.2%, and the activities of SOD, POD and CAT in leaves under microbial inoculum treatment were increased by 36.9%-42.6%, 82.7%-92.6% and 43.3%-52.2%, respectively, with the stimulative effects on antioxidation enzymes in rice leaves being higher than those of bacteria suspension. Compared with cadmium treatment, the contents of MDA and O2-· in rice leaves were reduced by 44.8%-54.7%, 29.4%-41.9% and 9.9%-10.2%, 3.0%-7.1% in microbial inoculum and bacteria suspension treatments, respectively. In contrast, the contents of flavonoids and total phenols were increased by 125.4%-135.7%, 100.8%-119.4% and 139.4%-146.7%, 115.0%-134.7%, respectively. In summary, P. aeruginosa and the microbial inoculum could promote rice seedling growth by improving root vigor and photosynthetic rate, as well as the contents of flavonoids and total phenols, which led to the fact that P. aeruginosa could significantly alleviate the stress of cadmium on rice.


Assuntos
Cádmio/toxicidade , Oryza/fisiologia , Folhas de Planta/fisiologia , Raízes de Plantas/fisiologia , Pseudomonas aeruginosa/fisiologia , Poluentes do Solo/toxicidade , Oryza/microbiologia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Plântula , Estresse Fisiológico
5.
Bioengineered ; 10(1): 316-334, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31347943

RESUMO

In the development of medicinally important Orchidaceae, the extent of fungal endophytes specificity is not presently very clear. Limited study has been available on natural products formed and its role on plant growth, defence mechanism by endophytes, and to characterize the chief treasure of bioactive molecules. Therefore, this review article presents an evaluation of the endophytes associated with Orchidaceae for physiology, metabolism, and genomics which have prominently contributed to the resurgence of novel metabolite research increasing our considerate of multifaceted mechanisms regulatory appearance of biosynthetic gene groups encoding diverse metabolites. Additionally, we presented the comprehensive recent development of bio-strategies for the cultivation of endophytes from Orchidaceae and integration of bioengineered 'Genomics with metabolism' approaches with emphases collective omics as powerful approach to discover novel metabolite compounds. The Orchidaceae-fungal endophytes' biodynamics for sustainable development of bioproducts and its applications are supported in large-scale biosynthesis of industrially and pharmaceutical important biomolecules.


Assuntos
Produtos Biológicos/química , Endófitos/metabolismo , Fungos/metabolismo , Orchidaceae/microbiologia , Simbiose/fisiologia , Produtos Biológicos/isolamento & purificação , Endófitos/classificação , Endófitos/genética , Fungos/classificação , Fungos/genética , Redes e Vias Metabólicas/fisiologia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Metabolismo Secundário/fisiologia
6.
BMC Plant Biol ; 19(1): 288, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262271

RESUMO

BACKGROUND: Clubroot disease caused by Plasmodiophora brassicae (Phytomyxea, Rhizaria) is one of the economically most important diseases of Brassica crops. The formation of hypertrophied roots accompanied by altered metabolism and hormone homeostasis is typical for infected plants. Not all roots of infected plants show the same phenotypic changes. While some roots remain uninfected, others develop galls of diverse size. The aim of this study was to analyse and compare the intra-plant heterogeneity of P. brassicae root galls and symptomless roots of the same host plants (Brassica oleracea var. gongylodes) collected from a commercial field in Austria using transcriptome analyses. RESULTS: Transcriptomes were markedly different between symptomless roots and gall tissue. Symptomless roots showed transcriptomic traits previously described for resistant plants. Genes involved in host cell wall synthesis and reinforcement were up-regulated in symptomless roots indicating elevated tolerance against P. brassicae. By contrast, genes involved in cell wall degradation and modification processes like expansion were up-regulated in root galls. Hormone metabolism differed between symptomless roots and galls. Brassinosteroid-synthesis was down-regulated in root galls, whereas jasmonic acid synthesis was down-regulated in symptomless roots. Cytokinin metabolism and signalling were up-regulated in symptomless roots with the exception of one CKX6 homolog, which was strongly down-regulated. Salicylic acid (SA) mediated defence response was up-regulated in symptomless roots, compared with root gall tissue. This is probably caused by a secreted benzoic acid/salicylic acid methyl transferase from the pathogen (PbBSMT), which was one of the highest expressed pathogen genes in gall tissue. The PbBSMT derived Methyl-SA potentially leads to increased pathogen tolerance in uninfected roots. CONCLUSIONS: Infected and uninfected roots of clubroot infected plants showed transcriptomic differences similar to those previously described between clubroot resistant and susceptible hosts. The here described intra-plant heterogeneity suggests, that for a better understanding of clubroot disease targeted, spatial analyses of clubroot infected plants will be vital in understanding this economically important disease.


Assuntos
Brassica/genética , Doenças das Plantas/microbiologia , Plasmodioforídeos/fisiologia , Transcriptoma , Brassica/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/microbiologia
7.
J Agric Food Chem ; 67(31): 8536-8547, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31310520

RESUMO

Watermelon Fusarium wilt is a common soil-borne disease that has significantly affected its yield. In this study, fusaric acid-deficient mutant designated as ΔFUBT (mutated from Fusarium oxysporum f. sp. niveum, FON) was obtained. The ΔFUBT mutant showed significant decrease in fusaric acid production but maintained wild-type characteristics, such as in vitro colony morphology, size, and conidiation. A field pot experiment demonstrated that ΔFUBT could successfully colonize the rhizosphere and the roots of watermelon, leading to significant reduction in FON colonization in the watermelon plant. In addition, ΔFUBT inoculation significantly improved the rhizosphere microenvironment and effectively increased the resistance in watermelon. This study demonstrated that a nonpathogenic Fusarium mutant (ΔFUBT) could be developed as an effective microbial control agent to alleviate Fusarium wilt disease in watermelon and increase its yield.


Assuntos
Citrullus/microbiologia , Fusarium/genética , Micotoxinas/genética , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ácido Fusárico/metabolismo , Fusarium/crescimento & desenvolvimento , Fusarium/fisiologia , Mutação , Micotoxinas/metabolismo , Raízes de Plantas/microbiologia , Rizosfera
8.
J Agric Food Chem ; 67(31): 8493-8499, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31310523

RESUMO

The ginsenosides Rh2 and Rg3 induce tumor cell apoptosis, inhibit tumor cell proliferation, and restrain tumor invasion and metastasis. Despite Rh2 and Rg3 having versatile pharmacological activities, contents of them in natural ginseng are extremely low. To produce ginsenosides Rh2 and Rg3, the saponin-producing capacity of endophytic bacteria isolated from Panax ginseng was investigated. In this work, 81 endophytic bacteria isolates were taken from ginseng roots by tissue separation methods. Among them, strain PDA-2 showed the highest capacity to produce the rare ginsenosides; the concentrations of rare ginsenosides Rg3 and Rh2 reached 62.20 and 18.60 mg/L, respectively. On the basis of phylogenetic analysis, it was found that strain PDA-2 belongs to the genus Agrobacterium and was very close to Agrobacterium rhizogenes.


Assuntos
Bactérias/metabolismo , Endófitos/metabolismo , Ginsenosídeos/biossíntese , Panax/microbiologia , Agrobacterium/classificação , Agrobacterium/genética , Agrobacterium/isolamento & purificação , Agrobacterium/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Endófitos/classificação , Endófitos/genética , Endófitos/isolamento & purificação , Filogenia , Raízes de Plantas/microbiologia
9.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2056-2062, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257779

RESUMO

The endophytic bacteria were isolated from the roots of polycyclic aromatic hydrocarbon (PAHs)-tolerant plant. We investigated their ability of PAHs degradation and plant growth promo-ting, with the aim to provide theoretical support for bacterial-plant cooperative soil remediation. Kochia scoparia living in coking plant area were selected for strains isolation. Eight endophytic bacteria strains, which used pyrene and 1-aminocyclopropane-1-carboxylic acid (ACC) as sole carbon and nitrogen source, were isolated from the roots of K. scoparia. Three endophytic bacteria, KSE4, KSE7 and KSE8, displayed high degradation efficiency in pyrene degradation experiment. They were identified as Bacillus sp., Pseudomonas sp., and Sphingobacterium sp., respectively. The abili-ties of those three strains to produce ACC deaminase and their effects on seed germination of K. scoparia were examined under pyrene stress through liquid culture tests. The results showed that the activity of ACC deaminase decreased with increasing pyrene concentration (0-15 mg·L-1). KSE7 had the strongest promotion effect. When pyrene concentration reached to 15 mg·L-1, the germination rate and bud length of K. scoparia increased by 44.8% and 61.1%, respectively. Our results indicated that KSE7 is a promising bacterial strain for soil remediation in coking plant area.


Assuntos
Bassia scoparia/metabolismo , Biodegradação Ambiental , Raízes de Plantas/microbiologia , Pirenos/metabolismo , Poluentes do Solo/metabolismo , Bactérias , Hidrocarbonetos Policíclicos Aromáticos
10.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2063-2071, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257780

RESUMO

Arbuscular mycorrhizal fungi (AMF) play an important role in plant growth enhancement, tolerance to heavy metal toxicity, and rehabilitation of contaminated ecosystems. An experiment was carried out with Phragmites communis and Pennisetum alopecuroides inoculated with or without Funneliformis mosseae (Fm), or Rhizophagus intraradices (Ri) under the simulated wetland system with Cd polluted water (0, 5, 10 or 20 mg·L-1). The results showed that Cd addition significantly decreased mycorrhizal colonization. AMF increased plant height, dry mass, leaf chlorophyll, N and Cd contents in shoot and root of P. communis and P. alopecuroides, enhanced Cd enrichment capability by roots, and decreased Cd transfer coefficient. Under Cd 5 mg·L-1 treatment, all of the indices in Fm + P. communis combination treatment were higher than those of other treatments, with 60.6% of AMF colonization, and the entry points and vesicles per mm root length were 2.3 and 3.7, respectively. Under the inoculation treatment, dry mass of shoot and root was improved by 69.1%, and 75.0%, nitrogen contents in shoot and root were increased by 38.7% and 27.8%, and the chlorophyll content and plant height were increased by 3.8% and 11.1%, respectively. There was a significant positive correlation between Cd concentration in wetland system and Cd content in shoot and root. Under Cd 20 mg·L-1 treatment, Fm + P. communis combination had the maximum Cd contents of 182.4 mg·kg-1 and 663.3 mg·kg-1 in shoot and root, respectively, the lowest Cd transfer coefficient (0.27), and the highest enrichment coefficient (0.55). In conclusion, Fm + P. communis was the best combination for absorbing Cd in polluted water.


Assuntos
Cádmio/metabolismo , Glomeromycota , Micorrizas/fisiologia , Raízes de Plantas/microbiologia , Poluentes do Solo/metabolismo , Áreas Alagadas
11.
Int J Syst Evol Microbiol ; 69(9): 2884-2891, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31310194

RESUMO

A novel endophytic actinomycete strain AZ1-13T was isolated from roots of Azadirachta indica, and its taxonomic position was investigated using a polyphasic approach. Pairwise 16S rRNA gene sequence similarities of strain AZ1-13T and its closest species, Jishegella zingiberis PLAI1-1T and Micromonospora endophytica 202201T, were 99.7 and 99.2 %, respectively. Phylogenetic analyses of the family Micromonosporaceae based on 16S rRNA gene sequences indicated strains AZ1-13T and J. zingiberis PLAI1-1Tare located within the genus Micromonospora. The approximate genome size of the strain was 5.96 Mb with 71.9 mol% of G+C content. The strain AZ1-13T exhibited ANIb values of 87.4 % with J. zingiberis PLAI1-1T and 85.1 % with M. endophytica 202201T. Chemotaxonomic characteristics of strain AZ1-13T were consistent within the genus Micromonospora: cell-wall peptidoglycan of the strain contained meso-diaminopimelic acid; glucose, mannose, ribose and xylose are presented as the whole-cell sugars; the predominant menaquinones were MK-9(H4) and MK-9(H6); major cellular fatty acids were iso-C15 : 0, 10-methyl C17 : 0, C17 : 0, anteiso-C17 : 0 and iso-C17 : 1ω8c; diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol were detected as distinguished phospholipids. Based on phenotypic properties, phylogeny and genomic data, the strain AZ1-13T could be distinguished from its closest neighbours, representing a novel species of the genus Micromonospora, for which the name Micromonospora radicis sp. nov. is proposed. The type strain is AZ1-13T (=KCTC 39786T=NBRC 112324T=JCM 32147T = TISTR 2404T). This study also proposed that J. zingiberisis transferred to the genus Micromonospora as Micromonospora zingiberis comb. nov. (type strain PLAI1-1T=TBRC 7644T=NBRC 113144T=JCM 32592T).


Assuntos
Azadirachta/microbiologia , Micromonospora/classificação , Filogenia , Raízes de Plantas/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Micromonospora/isolamento & purificação , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tailândia , Vitamina K 2/análogos & derivados , Vitamina K 2/química
12.
World J Microbiol Biotechnol ; 35(8): 117, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332532

RESUMO

Iron- and sulfur-oxidizing bacteria inhabiting rice rhizoplane play a significant role on arsenic biogeochemistry in flooded rice paddies, influencing arsenic translocation to rice grains. In the present study, the selective pressure of arsenic species on these microbial populations was evaluated. Rice roots from continuously flooded plants were incubated in iron sulfide (FeS) gradient tubes and exposed to either arsenate or arsenite. The biomass developed in the visible iron-oxidation band of the enrichments was analyzed by Scanning Electron Microscopy and Energy-Dispersive Spectroscopy (SEM-EDS) and the bacterial communities were characterized by 16S rRNA gene sequencing. Different Proteobacteria communities were selected depending on exposure to arsenate and arsenite. Arsenate addition favored the versatile iron-oxidizers Dechloromonas and Azospira, associated to putative iron (hydr)oxide crystals. Arsenite exposure decreased the diversity in the enrichments, with the development of the sulfur-oxidizer Thiobacillus thioparus, likely growing on sulfide released by FeS. Whereas sulfur-oxidizers were observed in all treatments, iron-oxidizers disappeared when exposed to arsenite. These results reveal a strong impact of different inorganic arsenics on rhizospheric iron-oxidizers as well as a crucial role of sulfur-oxidizing bacteria in establishing rice rhizosphere communities under arsenic pressure.


Assuntos
Arsênico/metabolismo , DNA Bacteriano/isolamento & purificação , Oryza/efeitos dos fármacos , Oryza/microbiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/microbiologia , Arseniatos/metabolismo , Arsenitos/metabolismo , DNA Bacteriano/genética , Ferro/metabolismo , Oxirredução , Proteobactérias/efeitos dos fármacos , Proteobactérias/isolamento & purificação , Proteobactérias/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação , Solo/química , Microbiologia do Solo , Poluentes do Solo/metabolismo , Enxofre/metabolismo
13.
Sci Total Environ ; 690: 841-852, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31302549

RESUMO

To promote agronomic sustainability, extensive research is being carried out globally, investigating biofertilizer development. Recently, it has been realized that some microorganisms used as biofertilizers behave as opportunistic pathogens and belong to the biosafety level 2 (BSL-2) classification. This poses serious risk to the environmental and human health. Evidence presented in various scientific forums is increasingly favoring the merits of using BSL-2 microorganisms as biofertilizers. In this review, we emphasize that partial characterization based on traditional microbiological approaches and small subunit rRNA gene sequences/conserved regions are insufficient for the characterization of biofertilizer strains. It is advised herein, that research and industrial laboratories developing biofertilizers for commercialization or environmental release must characterize microorganisms of interest using a multilateral polyphasic approach of microbial systematics. This will determine their risk group and biosafety characteristics before proceeding with formulation development and environmental application. It has also been suggested that microorganisms belonging to risk-group-1 and BSL-1 category should be used for formulation development and for field scale applications. While, BSL-2 microorganisms should be restricted for research using containment practices compliant with strict regulations.


Assuntos
Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Microbiologia do Solo , Agricultura , Contenção de Riscos Biológicos , Laboratórios
14.
Zhongguo Zhong Yao Za Zhi ; 44(10): 2015-2019, 2019 May.
Artigo em Chinês | MEDLINE | ID: mdl-31355554

RESUMO

This study was aimed to clarify the toxicity indoor and inhibition effect of biocontrol strain NJ13 and its mixture with chemical fungicides against Fusarium solani causing ginseng root rot. The method of mycelial growth rate and Sun Yunpei method were used to determine the indoor toxicity and co-toxicity coefficient of strain NJ13 and their mixture with chemical pesticides against F. solani. The dual culture assay method,mixed culture method and microscopic observation were used to determine the sporulation and germination of spores and mycelial growth and morphological change of hyphae of F. solani treated by strain NJ13. The results of toxicity indoor showed that strain NJ13 had the best inhibitory effect on pathogen,and its EC_(50) value was 0. 071 mg·L~(-1). It was all synergistic for antifungal effect that strain NJ13 was mixed with propiconazole and difenoconazole respectively with a range from 1 ∶4 to 4 ∶1( volume ratio). Both of optimal ratios were 1 ∶1,and the co-toxicity coefficients were 848. 70 and 859. 73,respectively. The strain NJ13 could inhibit the sporulation,germination and mycelial growth of F. solani. The biocontrol strain NJ13 had an inhibition effect on F. solani,and the optimal antifungal ratio of strain NJ13 mixed with propiconazole and difenoconazole was obtained.


Assuntos
Bactérias , Agentes de Controle Biológico , Fungicidas Industriais , Fusarium/patogenicidade , Panax/microbiologia , Raízes de Plantas/microbiologia
15.
Plant Dis ; 103(9): 2417-2424, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31322978

RESUMO

Macrophomina phaseolina, the causal agent of charcoal rot, affects strawberry crowns, inducing plant collapse. The fungus survives in the soil through the production of microsclerotia and is usually controlled by preplant fumigation of soil. However, in the 2016 to 2017 Florida strawberry season, even after soil fumigation, about 30% plant mortality still occurred in plastic-covered beds that were used for a second season and where crop residue (mainly old strawberry crowns) was disposed of between beds. Therefore, this study was conducted to determine if M. phaseolina can survive on strawberry debris over summer in Florida and if so, verify whether strawberry debris might act as a source of inoculum for new transplants. Crowns from the previous season were collected from commercial farms where charcoal rot had been reported, and M. phaseolina was recovered from all samples. In a research field, infected crowns were buried in the soil at different depths and retrieved every 2 weeks during the summer. After 8 weeks, M. phaseolina could be recovered at all depths. Moreover, inoculation of strawberry plants by drenching the soil, dipping roots, or spraying leaves with a M. phaseolina microsclerotial suspension from pure cultures or infected crowns produced symptoms with differences in incubation periods depending on cultivar susceptibility. Furthermore, infected crowns disposed of in the aisles between beds or buried next to new transplants of cultivars Strawberry Festival, Florida Beauty, and Winterstar induced charcoal rot, with the level of aggressiveness depending on the cultivar susceptibility and inoculum placement in the field.


Assuntos
Ascomicetos , Fragaria , Doenças das Plantas , Ascomicetos/fisiologia , Florida , Fragaria/microbiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia
16.
World J Microbiol Biotechnol ; 35(6): 90, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147784

RESUMO

The ability of plant growth promoting rhizobacteria (PGPR) for imparting abiotic stress tolerance to plants has been widely explored in recent years; however, the diversity and potential of these microbes have not been maximally exploited. In this study, we characterized four bacterial strains, namely, Pseudomonas aeruginosa PM389, Pseudomonas aeruginosa ZNP1, Bacillus endophyticus J13 and Bacillus tequilensis J12, for potential plant growth promoting (PGP) traits under osmotic-stress, induced by 25% polyethylene glycol (PEG) in the growth medium. Growth curve analysis was performed in LB medium with or without PEG, in order to understand the growth patterns of these bacteria under osmotic-stress. All strains were able to grow and proliferate under osmotic-stress, although their growth rate was slower than that under non-stressed conditions (LB without PEG). Bacterial secretions were analyzed for the presence of exopolysaccharides and phytohormones and it was observed that all four strains released these compounds into the media, both, under stressed and non-stressed conditions. In the Pseudomonas strains, osmotic stress caused a decrease in the levels of auxin (IAA) and cytokinin (tZ), but an increase in the levels of gibberellic acid. The Bacillus strains on the other hand showed a stress-induced increase in the levels of all three phytohormones. P. aeruginosa ZNP1 and B. endophyticus J13 exhibited increased EPS production under osmotic-stress. While osmotic stress caused a decrease in the levels of EPS in P. aeruginosa PM389, B. tequilensis J12 showed no change in EPS quantities released into the media under osmotic stress when compared to non-stressed conditions. Upon inoculating Arabidopsis thaliana seedlings with these strains individually, it was observed that all four strains were able to ameliorate the adverse effects of osmotic-stress (induced by 25% PEG in MS-Agar medium) in the plants, as evidenced by their enhanced fresh weight, dry weight and plant water content, as opposed to osmotic-stressed, non-inoculated plants.


Assuntos
Arabidopsis/microbiologia , Fenômenos Fisiológicos Bacterianos , Secas , Pressão Osmótica , Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/metabolismo , Polissacarídeos Bacterianos/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Bacillus/crescimento & desenvolvimento , Bacillus/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Citocininas/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Rizosfera , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Estresse Fisiológico/fisiologia
17.
World J Microbiol Biotechnol ; 35(7): 104, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31236765

RESUMO

Endophytic bacterial diversity in plants presents the level of interaction between culturable and non-culturable endophytic bacteria, thereby providing an appropriate insight into the endophytic environment. This study was conducted to determine the trend of culturable and non-culturable endophytic bacteria at two different sites encompassing four consecutive growth stages. For culturable endophytic bacteria, isolation was carried out using the dilution plate technique, and the obtained colonies were compared using PCR-restriction fragment length polymorphism (RFLP). Different RFLP-types were identified to their nearest neighbour using 16S rRNA sequencing. The non-culturable endophytic bacterial diversity was obtained by next generation sequencing. Results suggested a similar trend among the culturable and non-culturable bacteria for observed operational taxonomic units and diversity indices. It is noticeable that the endophytic bacteria inhabiting in stage 1 disappeared, and instead, different endophytic bacteria appeared. Moreover, the temporal persistence of certain culturable and non-culturable bacteria was also observed. In conclusion, the endophytic bacterial diversity in cucumber initially increased with the plant growth and then decreased at a later stage. Furthermore, it was suggested that plants regulate the number and diversity of endophytes throughout the lifecycle of plants.


Assuntos
Bactérias/classificação , Bactérias/isolamento & purificação , Biodiversidade , Cucumis sativus/microbiologia , Endófitos/classificação , Endófitos/isolamento & purificação , Microbiota , Bactérias/genética , Cucumis sativus/crescimento & desenvolvimento , DNA Bacteriano/análise , DNA Bacteriano/isolamento & purificação , Endófitos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Microbiota/genética , Filogenia , Raízes de Plantas/microbiologia , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética
19.
BMC Plant Biol ; 19(1): 284, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253081

RESUMO

BACKGROUND: Echinacea-endophyte interaction might affect plant secondary metabolites content and influence bacterial colonization specificity and plant growth, but the underlying mechanisms need deepening. An in vitro model, in which E. purpurea axenic plants as host species and E. angustifolia and Nicotiana tabacum as non-host species inoculated with single endophytes isolated from stem/leaf, root and rhizospheric soil, were used to investigate bacterial colonization. RESULTS: Colonization analysis showed that bacteria tended to reach tissues from which they were originally isolated (tissue-specificity) in host plants but not in non-host ones (species-specificity). Primary root elongation inhibition as well as the promotion of the growth of E. purpurea and E. angustifolia plants were observed and related to endophyte-produced indole-3-Acetic Acid. Bacteria-secreted substances affected plant physiology probably interacting with plant regulators. Plant metabolites played an important role in controlling the endophyte growth. CONCLUSIONS: The proposed in vitro infection model could be, generally used to identify novel bioactive compounds and/or to select specific endophytes contributing to the host metabolism properties.


Assuntos
Bactérias/crescimento & desenvolvimento , Echinacea/microbiologia , Endófitos/crescimento & desenvolvimento , Microbiologia do Solo , Echinacea/crescimento & desenvolvimento , Especificidade de Órgãos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Rizosfera , Tabaco/crescimento & desenvolvimento , Tabaco/microbiologia
20.
Chemosphere ; 232: 439-452, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31158639

RESUMO

This study investigated the role of an allochthonous Gram-positive wastewater bacterium (Bacillus sp. KUJM2) selected through rigorous screening, for the removal of potentially toxic elements (PTEs; As, Cd, Cu, Ni) and promotion of plant growth under PTE-stress conditions. The dried biomass of the bacterial strain removed PTEs (5 mg L-1) from water by 90.17-94.75 and 60.4-81.41%, whereas live cells removed 87.15-91.69 and 57.5-78.8%, respectively, under single-PTE and co-contaminated conditions. When subjected to a single PTE, the bacterial production of indole-3-acetic acid (IAA) reached the maxima with Cu (67.66%) and Ni (64.33%), but Cd showed an inhibitory effect beyond 5 mg L-1 level. The multiple-PTE treatment induced IAA production only up to 5 mg L-1 beyond which inhibition ensued. Enhanced germination rate, germination index and seed production of lentil plant (Lens culinaris) under the bacterial inoculation indicated the plant growth promotion potential of the microbial strain. Lentil plants, as a result of bacterial inoculation, responded with higher shoot length (7.1-27.61%), shoot dry weight (18.22-36.3%) and seed production (19.23-29.17%) under PTE-stress conditions. The PTE uptake in lentil shoots decreased by 67.02-79.85% and 65.94-78.08%, respectively, under single- and multiple-PTE contaminated conditions. Similarly, PTE uptake was reduced in seeds up to 72.82-86.62% and 68.68-85.94%, respectively. The bacteria-mediated inhibition of PTE translocation in lentil plant was confirmed from the translocation factor of the respective PTEs. Thus, the selected bacterium (Bacillus sp. KUJM2) offered considerable potential as a PTE remediating agent, plant growth promoter and regulator of PTE translocation curtailing environmental and human health risks.


Assuntos
Bacillus/crescimento & desenvolvimento , Lens (Planta)/crescimento & desenvolvimento , Poluentes do Solo/análise , Águas Residuárias/microbiologia , Bacillus/metabolismo , Biodegradação Ambiental , Germinação/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Lens (Planta)/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poluentes do Solo/toxicidade
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