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1.
Arch Microbiol ; 202(7): 1899-1906, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32448960

RESUMO

Endophytic bacteria have been reported to have symbiotic, mutualistic, commensalistic or trophobiotic relationships with various plant parts. As part of its adaptation, many endophytic organisms are known to exhibit properties with multiple beneficial effects to the plant system. Even though many bacterial genera have been identified to have endophytic association, isolation of those which were previously demonstrated well for human association is quite interesting. In the study, endophytic bacteria Ceb1 isolated from the rhizome of Curcuma longa was identified by 16S rDNA sequencing as Staphylococcus sp. Further, Ceb1 was observed to have the ability to tolerate drought stress. While screening for the plant growth-promoting traits, Ceb1 was found to be positive for IAA production both under drought-stressed and normal conditions as confirmed by HPLC. The Ceb1 priming with Vigna unguiculata was observed to enhance the growth parameters of the plant. Analysis of Ceb1-treated plants by ICP-MS further showed modulation of both macro- and micronutrients. Upon drought stress induction in Vigna unguiculata, Ceb1 was found to provide synergistic plant growth-promoting effect to the plant along with the supplemented silicate sources. Under the changing agroclimatic conditions, exploring the plant stress-alleviating effects of endophytes is highly significant.


Assuntos
Secas , Desenvolvimento Vegetal , Plantas/microbiologia , Silicatos/farmacologia , Staphylococcus/fisiologia , Curcuma/microbiologia , Endófitos/classificação , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/metabolismo , Desenvolvimento Vegetal/fisiologia , RNA Ribossômico 16S/genética , Rizoma/microbiologia , Staphylococcus/genética , Staphylococcus/isolamento & purificação , Simbiose , Vigna/fisiologia
2.
Microbiol Res ; 236: 126467, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32248049

RESUMO

Strains of Xylella fastidiosa subsp. pauca characterized by a specific genotype, the so called sequence type "ST53", have been associated with a severe disease named Olive Quick Decline Syndrome (OQDS). Despite the relevant research efforts devoted to control the disease caused by X. fastidiosa, so far there are no therapeutic means able to cure the infected host plants. As such, the aim of this study was the identification of antagonistic bacteria potentially deployable as bio-control agents against X. fastidiosa. To this end, two approaches were used, i.e. the evaluation of the antagonistic activity of: i) endophytic bacteria isolated from olive trees located in an infected area but showing mild or no symptoms, and ii) Bacillus strains, as they are already known as bio-control agents. Characterization of endophytic bacterial isolates revealed that the majority belonged to different species of the genera Sphingomonas, Methylobacterium, Micrococcus and Curtobacterium. However, when they were tested in vitro against X. fastidiosa ST53 none of them showed antagonistic activity. On the contrary, when strains belonging to different species of the genus Bacillus were included in these tests, remarkable antagonistic activities were recorded. Some B. velezensis strains also produced culture filtrates with inhibitory activity against X. fastidiosa ST53. Taking also into account that two of these B. velezensis strains (namely strains D747 and QST713) are already registered and commercially available as bio-control agents, our results pave the way for further studies aimed at the development of a sustainable bio-control strategy of the OQDS.


Assuntos
Antibiose , Bacillus , Endófitos/isolamento & purificação , Olea/microbiologia , Xylella , Bacillus/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Agentes de Controle Biológico/farmacologia , DNA Bacteriano/genética , Endófitos/genética , Endófitos/metabolismo , Patologia Molecular , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , Xylella/patogenicidade
3.
PLoS One ; 15(4): e0232096, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32339210

RESUMO

Endophytic bacteria, which are common in plant tissues, may help to control plant pathogens and enhance plant growth. Camellia oleifera, an oil-producing plant, is widely grown in warm, subtropical, hilly regions in China. However, C. oleifera is strongly negatively affected by C. oleifera anthracnose, which is caused by Colletetrichum fructicola. To find a suitable biocontrol agent for C. oleifera anthracnose, 41 endophytes were isolated from the stems, leaves, and roots of C. oleifera. Bacterial cultures were identified based on analyses of 16S rDNA sequences; most strains belonged to the genus Bacillus. The antagonistic effects of these strains on C. fructicola were tested in vitro. In total, 16 strains inhibited C. fructicola growth, with B. subtilis strain 1-L-29 being the most efficient. Strain 1-L-29 demonstrated antagonistic activity against C. siamense, C. asianum, Fusarium proliferatum, Agaricodochium camellia, and Pseudomonas syringae. In addition, this strain produced indole acetic acid, solubilized phosphate, grew on N-free media, and produced siderophores. To facilitate further microecological studies of this strain, a rifampicin-resistant, green fluorescent protein (GFP)-labeled strain, 1-L-29gfpr, was created using protoplast transformation. This plasmid had good segregational stability. Strain 1-L-29gfpr was re-introduced into C. oleifera and successfully colonized root, stem, and leaf tissues. This strain remained at a stable concentration in the root more than 20 d after inoculation. Fluorescence microscopic analysis showed that strain 1-L-29gfpr thoroughly colonized the root surfaces of C. fructicola as well as the root vascular tissues of Arabidopsis thaliana.


Assuntos
Antibacterianos/metabolismo , Bacillus subtilis/metabolismo , Camellia/crescimento & desenvolvimento , Endófitos/metabolismo , Doenças das Plantas/prevenção & controle , Raízes de Plantas/crescimento & desenvolvimento , Bacillus subtilis/classificação , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/isolamento & purificação , Camellia/metabolismo , Camellia/microbiologia , Endófitos/crescimento & desenvolvimento , Endófitos/isolamento & purificação , Controle Biológico de Vetores , Desenvolvimento Vegetal , Doenças das Plantas/microbiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia
4.
Microbiol Res ; 236: 126451, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32146294

RESUMO

Burkholderia species have different lifestyles establishing mutualist or pathogenic associations with plants and animals. Changes in the ecological behavior of these bacteria may depend on genetic variations in response to niche adaptation. Here, we studied 15 Burkholderia strains isolated from different environments with respect to genetic and phenotypic traits. By Multilocus Sequence Analysis (MLSA) these isolates fell into 6 distinct groups. MLSA clusters did not correlate with strain antibiotic sensitivity, but with the bacterial ability to produce antimicrobial compounds and control orchid necrosis. Further, the B. seminalis strain TC3.4.2R3, a mutualistic bacterium, was inoculated into orchid plants and the interaction with the host was evaluated by analyzing the plant response and the bacterial oxidative stress response in planta. TC3.4.2R3 responded to plant colonization by increasing its own growth rate and by differential gene regulation upon oxidative stress caused by the plant, while reducing the plant's membrane lipid peroxidation. The bacterial responses to oxidative stress were recapitulated by bacterial exposure to the herbicide paraquat. We suggest that the ability of Burkholderia species to successfully establish in the rhizosphere correlates with genetic variation, whereas traits associated with antibiotic resistance are more likely to be categorized as strain specific.


Assuntos
Adaptação Biológica/genética , Infecções por Burkholderia , Burkholderia , Interações entre Hospedeiro e Microrganismos , Orchidaceae/microbiologia , Aclimatação/genética , Anti-Infecciosos/farmacologia , Agentes de Controle Biológico/farmacologia , Burkholderia/genética , Burkholderia/crescimento & desenvolvimento , Burkholderia/isolamento & purificação , Burkholderia/metabolismo , Resistência Microbiana a Medicamentos/genética , Endófitos/genética , Endófitos/crescimento & desenvolvimento , Endófitos/isolamento & purificação , Endófitos/metabolismo , Genes Bacterianos , Ilhas Genômicas , Genótipo , Peroxidação de Lipídeos , Tipagem de Sequências Multilocus , Orchidaceae/fisiologia , Estresse Oxidativo/genética , Fenótipo , Filogenia , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , RNA Ribossômico 16S/genética , Simbiose , Transcriptoma
5.
J Chem Ecol ; 46(4): 410-421, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32125583

RESUMO

The symbiotic Epichloë festucae var. lolii endophyte produces alkaloids which can provide its host grass, perennial ryegrass (Lolium perenne L), with a selective advantage in both natural and agricultural managed ecosystems. This study focuses on understanding the alkaloid concentrations that occur in endophyte-infected perennial ryegrass during the early establishment phase. In a glasshouse experiment fungal alkaloid concentrations (peramine, lolitrem B, ergovaline, and epoxy-janthitrems) were measured in perennial ryegrass seedlings infected with E. festucae var. lolii proprietary strains AR1, AR37, NEA2, and NZ common toxic for 69 days after sowing. The endophyte becomes metabolically active, starting alkaloid production, as early as 6 days after sowing. Alkaloid concentrations peaked in 8- to 10- day-old seedlings due to a seedling growth slowdown. This study provides data showing that the loss of insect protection in endophyte-infected seedlings is linked to a reduction in chemical defence after seed-stored, maternally synthesised alkaloids are diluted by seedling dry matter accumulation.


Assuntos
Alcaloides/metabolismo , Endófitos/metabolismo , Epichloe/metabolismo , Lolium/crescimento & desenvolvimento , Lolium/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Simbiose
6.
J Agric Food Chem ; 68(6): 1588-1595, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31994388

RESUMO

The discovery of new, safe, and effective pesticides is one of the main means for modern crop protection and parasitic disease control. During the search for new insecticidal secondary metabolites from endophytes in Stemona sessilifolia (a traditional Chinese medicine with a long history as an insecticide), 10 new insecticidal endostemonines A-J (1-10) were identified from an endophytic Streptomyces sp. BS-1. Their structures were determined by comprehensive spectroscopic analysis. Endostemonines A-J represent the first reported naturally occurring pyrrole-2-carboxylic ester derivatives, which consisted of different fatty acid chains at the C-2 of pyrrole ring were produced by traditional Chinese medicine endophytic microbes. All new tested compounds exhibited strong lethal activity against Aphis gossypii (LC50 value range of 3.55-32.00 mg/L after 72 h). This research highlighted the discovery of pesticide natural products from insecticidal medicinal plant endophytes for the first time, paving a new pathway for the development of pest control.


Assuntos
Endófitos/química , Compostos Heterocíclicos com 3 Anéis/metabolismo , Inseticidas/metabolismo , Stemonaceae/microbiologia , Streptomyces/química , Streptomyces/metabolismo , Animais , Afídeos/efeitos dos fármacos , Endófitos/metabolismo , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/toxicidade , Inseticidas/química , Inseticidas/toxicidade , Metabolismo Secundário
7.
J Agric Food Chem ; 68(4): 1126-1135, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31891261

RESUMO

Phenylpropanoid (PPPN) compounds are widely used in agriculture, medical, food, and cosmetic industries because of their multiple bioactivities. Alternaria sp. MG1, an endophytic fungus isolated from grape, is a new natural source of PPPNs. However, the PPPN biosynthesis pathway in MG1 tends to be suppressed under normal growth conditions. Starvation has been reported to stimulate the PPPN pathway in plants, but this phenomenon has not been well studied in endophytic fungi. Here, metabolomics analysis was used to examine the profile of PPPN compounds, and quantitative reverse transcription-polymerase chain reaction was used to detect the expression of key genes in the PPPN biosynthesis pathway under starvation conditions. Starvation treatment significantly increased the accumulation of shikimate and PPPN compounds and upregulated the expression of key genes in their biosynthesis pathways. In addition to previously reported PPPNs, sinapate, 4-hydroxystyrene, piceatannol, and taxifolin were also detected under starvation treatment. These findings suggest that starvation treatment provides an effective way to optimize the production of PPPN compounds and may permit the investigation of compounds that are undetectable under normal conditions. Moreover, the diversity of its PPPNs makes strain MG1 a rich repository of valuable compounds and an extensive genetic resource for future studies.


Assuntos
Alternaria/metabolismo , Endófitos/metabolismo , Vitis/metabolismo , Vitis/microbiologia , Alternaria/genética , Alternaria/isolamento & purificação , Vias Biossintéticas , Ácidos Cumáricos/metabolismo , Endófitos/genética , Endófitos/isolamento & purificação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Metabolômica , Fenóis/metabolismo , Quercetina/análogos & derivados , Quercetina/biossíntese , Metabolismo Secundário , Estilbenos/metabolismo
8.
Chemosphere ; 246: 125759, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31891844

RESUMO

It is well known that microorganisms can reduce the effectiveness of organophosphate pesticides after their application. But, little information is available concerning the effect of rice endophytic bacteria on the degradation of diazinon, an organophosphate pesticide used in control of the rice stem-borer, absorbed by the rice plant. Thus, aim of this study was to characterize the endophytic bacterial isolates, isolated from diazinon-treated and non-treated rice plants in paddy fields, in terms of diazinon degradation and to investigate whether potent isolates that degrade diazinon in vitro might have the same effect in the rice plant. The results showed that all endophytic isolates, isolated from both groups of rice plants (diazinon-treated and non-treated rice plants), could grow in mineral salt medium (MSM) supplemented with diazinon (20 mg L-1) as a sole carbon source, and 3.79-58.52% of the initial dose of the insecticide was degraded by the isolates within 14 d of incubation. Phylogenetic analysis based on 16 S rRNA sequencing indicated that the potent isolates (DB26-R and B6-L) clearly belonged to the Bacillus genus. The diazinon concentrations in rice plants co-inoculated with B. altitudinis DB26-R and B. subtilis subsp. Inaquosorum B6-L and single-inoculated with these strains were reduced significantly compared with endophyte-free rice plants. These results provide unequivocal evidence that the rice endophytic bacteria, in addition to in vitro degradation of diazinon, are also involved in the rapid inactivation of diazinon in rice plants treated with diazinon (in vivo degradation of diazinon).


Assuntos
Diazinon/metabolismo , Endófitos/metabolismo , Inseticidas/metabolismo , Oryza/microbiologia , Animais , Biodegradação Ambiental , Diazinon/análise , Inseticidas/análise , Oryza/metabolismo , Filogenia
9.
Chemosphere ; 243: 125305, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31733539

RESUMO

Phenanthrene can easily be absorbed into the plant from the soil and cannot be effectively degraded in it. Thus, it is greatly hazardous for food safety and human health. In our study, the biodegradability and remediation mechanism of endophytic fungus Phomopsis liquidambaris on phenanthrene in vivo of rice (Oryza sativa L.) was detected. The results showed that the fungus could successfully establish a symbiotic relationship with rice, thus had the potential to degrade phenanthrene absorbed into the plant. Changes of phenanthrene-degrading genes of fungus in the combined system were consistent with the trends of their corresponding enzymatic activities, and the phenanthrene-degrading enzyme activities and gene expression levels in roots of rice were higher than those in the shoot. Moreover, the combined system can enhance bioremediation by increasing root viability, chlorophyll content, and energy supply. The combined system had also significantly increased the PPO activity and SOD activity in shoot compared with the control treatment, while decreased the content of MDA when remediation in vivo. The study on the degradation mechanism of the combined system will help us to increase the practical application potential of endophyte to effectively repair contamination absorbed into plant seedlings.


Assuntos
Biodegradação Ambiental , Endófitos/metabolismo , Fenantrenos/metabolismo , Endófitos/crescimento & desenvolvimento , Expressão Gênica , Genes Fúngicos , Oryza/microbiologia , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poluentes do Solo/análise , Poluentes do Solo/metabolismo
10.
Microbiol Res ; 231: 126371, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31734584

RESUMO

Eleven soil samples were collected from different plantations at the Forestry Model Base, Northeast Forestry University, China (45°43'10″N, 126°37'15″E), and 122 Trichoderma strains (T1-T122) were isolated. Nine Trichoderma species were identified based on morphological and molecular classification methods. The diversity of woody fungi was analyzed based on the type and quantity of Trichoderma spp. in the soil samples isolated from each plantation. Subdominant T. pseudoharzianum T17 (TpsT17) was screened and its biocontrol potential against Fusarium oxysporum CFCC86068 (Fox68) and growth promotion of Populus davidiana × P. alba var. pyramidalis (PdPap) seedlings were investigated. Compared with PdPap + Fox68 treatment, PdPap + TpsT17 + Fox68 treatment had an obvious antagonistic effect on Fox68 based on the status of roots and stomata of the poplar seedlings. In addition, pretreatment with TpsT17 increased catalase activity 14-fold and decreased hydrogen peroxide and malondialdehyde concentrations 2.57- and 7-fold, respectively, in the PdPap + TpsT17 + Fox68 treatment compared with the PdPap + Fox68 treatment. The transcription levels of PR1, JAZ6751, MYC2, MP, and JAR1 in PdPap + TpsT17+Fox68-treated plants were upregulated 5.75-, 5.63-, 14.88-, 8.24-, and 10.45-fold, respectively, at 3 d, while LAX2 exhibited little change in comparison with the level in PdPap + Fox-treated plants. TpsT17 was detected in the roots and stems of PdPap + TpsT17- and PdPap + TpsT17+Fox68-treated PdPap 28 d after inoculation, which demonstrated the endogenous capacity of TpsT17.


Assuntos
Endófitos/isolamento & purificação , Fusarium/crescimento & desenvolvimento , Populus , Trichoderma , Antibiose , Antifúngicos , Agentes de Controle Biológico , Catalase/metabolismo , DNA Espaçador Ribossômico , Endófitos/genética , Endófitos/metabolismo , Agricultura Florestal , Genes Fúngicos , Micoses/microbiologia , Filogenia , Doenças das Plantas/microbiologia , Imunidade Vegetal , Populus/enzimologia , Populus/microbiologia , Plântula/metabolismo , Microbiologia do Solo , Trichoderma/genética , Trichoderma/isolamento & purificação , Trichoderma/metabolismo
11.
J Appl Microbiol ; 128(3): 747-762, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31710165

RESUMO

AIMS: Different endophytic fungi were isolated and screened for their digoxin-producing ability. Strain improvement and different culture conditions were studied for more effective production of digoxin. METHODS AND RESULTS: Among the isolated fungi, an isolate produced digoxin in a concentration of 2·07 mg l-1 . The digoxin-producing fungal isolate was identified as Epicoccum nigrum Link according to the morphological features and phylogenetic analyses. The potentiality of the fungal strain for production enhancement of digoxin was performed by gamma radiation mutagenesis. Gamma irradiation dose of 1000 Gy intensified the digoxin yield by five-fold. Using this dose, a stable mutant strain with improved digoxin productivity was isolated and the stability for digoxin production was followed up across four successive generations. In the effort to increase digoxin magnitude, selection of the proper cultivation medium, addition of some elicitors to the most proper medium and several physical fermentation conditions were tested. Fermentation process carried out in malt extract autolysate medium (pH 6·5) supplemented by methyl jasmonate and inoculated with 2 ml of 6-day-old culture and incubated at 25°C for 10 days stimulated the highest production of digoxin to attain 50·14 mg l-1 . Moreover, cytotoxicity of digoxin separated from the fungal culture was tested against five different cancer cell lines. Based on the MTT assay, digoxin inhibited the proliferation of the five different cancer cell lines and the recorded 50% inhibitory concentration ranged from 10·76 to 35·14 µg ml-1 . CONCLUSIONS: This is the first report on the production and enhancement of digoxin using fungal fermentation as a new and alternate source with high productivity. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings offer new and alternate sources with excellent biotechnological potential for digoxin production by fungal fermentation. Moreover, digoxin proved to be a promising anticancer agent whose anticancer potential should be assessed in prospective cancer therapy.


Assuntos
Antineoplásicos/metabolismo , Ascomicetos/genética , Ascomicetos/metabolismo , Digoxina/metabolismo , Animais , Antineoplásicos/farmacologia , Ascomicetos/isolamento & purificação , Ascomicetos/efeitos da radiação , Células CHO , Linhagem Celular Tumoral , Cricetulus , Digoxina/farmacologia , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/metabolismo , Endófitos/efeitos da radiação , Fermentação , Raios gama , Humanos , Mutagênese , Filogenia
12.
J Agric Food Chem ; 68(1): 185-192, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31815467

RESUMO

Phytopathogenic fungi have been considered as being an enormous threat in the agricultural system. In our search of new antifungal natural products, nine new halogenated cyclopentenones, bicolorins A-I (1-3, and 5-10), along with three known cyclopentenones (4, 11, and 12) were isolated from the endophytic fungus Saccharicola bicolor of Bergenia purpurascens by the one strain-many compounds strategy. Their structures and absolute configurations were elucidated based on extensive spectroscopic analysis, X-ray crystallographic analysis, and time-dependent density functional theory-equivalent circulating density calculations. Compounds 1-12 showed antifungal activities against five phytopathogenic fungi (Uromyces viciae-fabae, Pythium dissimile, Gibberella zeae, Aspergillus niger, and Sclerotinia sclerotiorum). Especially, bicolorins B and D (2 and 5) exhibited strong antifungal activities against P. dissimile with the MIC values of 6.2 and 8.5 µg/mL, respectively, compared with the positive control cycloheximide (MIC of 8.6 µg/mL). Additionally, bicolorin D was proven to be potently antifungal against S. sclerotiorum in vitro and in vivo. This work provides an effective strategy for searching antifungal candidate agents.


Assuntos
Ascomicetos/química , Ciclopentanos/química , Ciclopentanos/farmacologia , Endófitos/química , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Saxifragaceae/microbiologia , Ascomicetos/isolamento & purificação , Ascomicetos/metabolismo , Ciclopentanos/metabolismo , Endófitos/isolamento & purificação , Endófitos/metabolismo , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungicidas Industriais/metabolismo , Halogenação , Estrutura Molecular , Doenças das Plantas/microbiologia
13.
Microbiol Res ; 232: 126386, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31816593

RESUMO

Fungal resistance against frequently used antifungal medicines used for invasive candidiasis and other fungal infections is directing scientist for searching and developing novel antifungal drugs. An endophytic fungal strain Alternaria tenuissima OE7 has been isolated from leaves of Ocimum tenuiflorum L. which showed antifungal activity against numbers of human pathogenic fungi including Trichophyton rubrum, Microsporum gypseum, Aspergillus parasiticus, A. flavus, A. fumigates, Candida albicans and C. tropicalis. Thermostable, non-proteinacious antifungal metabolites produced zones of inhibition against all pathogenic fungi tested. The ethyl acetate extract of the cell free supernatant was found inhibitory to the radial growth and conidial germination of T. rubrum and M. gypseum. It also showed cidal mode of action against C. albicans at a concentration of 1.0 mg/ml. Most interestingly, inhibition of biofilm formation and hyphal development of C. albicans were observed upon treatment with EA fraction at comparatively lower concentrations (100-500 µg/ml). Release of intracellular contents from treated cells of Candida and scanning electron microscopic observation suggested cellular disruptions by antifungal metabolites. Checkerboard study revealed synergy between EA fraction of OE7 (150 µg/ml) and fluconazole (30 µg/ml) with Æ©FIC of 0.45. Two active fractions viz. band 'C' and band 'G' derived after thin layer chromatographic analysis showed inhibitory activity against C. albicans with MIC values of 80 µg/ml and 130 µg/ml respectively. GCMS analysis suggested presence of numbers of compounds in each active fraction. Overall observations attest the prospective role of the isolate OE7 as a potent candidate for the production of antifungal metabolites against human pathogenic fungi.


Assuntos
Alternaria/metabolismo , Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Endófitos/metabolismo , Hifas/efeitos dos fármacos , Alternaria/isolamento & purificação , Antifúngicos/isolamento & purificação , Biofilmes/crescimento & desenvolvimento , Candidíase , Endófitos/isolamento & purificação , Fluconazol/farmacologia , Hifas/crescimento & desenvolvimento , Índia , Testes de Sensibilidade Microbiana , Ocimum sanctum/microbiologia , Metabolismo Secundário
14.
J Appl Microbiol ; 128(3): 814-827, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31710757

RESUMO

AIMS: Plant tissues are the reservoirs of beneficial and harmful microbes that regulates plant growth. In the present study, we investigated the diversity, function and colonization of sugarcane roots associated with Bacillus spp. METHODS AND RESULTS: A total of 20 Bacillus strains were isolated and identified by 16S rRNA gene sequencing, and their genetic diversity was examined by BOX, ERIC, REP, (GTG)5 PCR techniques. Among all Bacillus isolates, 65% showed indole acetic acid-like compounds production, 50% solubilized phosphorus and 25% of the isolates were able to secrete siderophore. Moreover, all 20 Bacillus isolates showed antifungal activity against eight fungal pathogens and 11 of them (55%) antagonized tomato grey mold. Based on the plant growth-promoting traits and antifungal potential, isolate Y8 was selected for root and plant tissue colonization assays and a greenhouse-level sugarcane growth promotion study. Fluorescence microscopy results confirmed that isolate Y8 has a strong ability to colonize in the sugarcane root and leaves, and the root surface association of Y8 was confirmed by scanning electron microscopy. Furthermore, greenhouse experimental results demonstrated that Y8 has a significant effect on enhancing sugarcane biomass and root length. CONCLUSIONS: Endophytic Bacillus strains have growth-promoting properties and anti-fungal ability that can enhance plant fitness in an eco-friendly manner. SIGNIFICANCE AND IMPACT OF THE STUDY: Endophytic Bacillus strains would be a potential alternative to chemical fertilizer as well as a biocontrol agent in the future.


Assuntos
Bacillus/isolamento & purificação , Bacillus/fisiologia , Saccharum/crescimento & desenvolvimento , Saccharum/microbiologia , Antifúngicos/metabolismo , Bacillus/genética , Bacillus/metabolismo , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/metabolismo , Endófitos/fisiologia , Fungos/classificação , Fungos/genética , Variação Genética , Ácidos Indolacéticos/metabolismo , Fósforo/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Sideróforos/metabolismo
15.
J Sci Food Agric ; 100(1): 441-446, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31512241

RESUMO

BACKGROUND: The production of mycelium from endophytic fungi is of interest for applications ranging from inoculants and biofertilizers for crop production to fermentations for enzyme and metabolite production. The purpose of this study was to test the capacity of a solid growth medium based on beet pulp for growing different strains of endophytes. RESULTS: The ergosterol content of inoculated medium was measured to estimate fungal growth. Several parameters related to the preparation of the growth medium, such as water content, calcium salts and incubation time, were evaluated. The greatest fungal biomass production was observed in a medium prepared with a 1:2 (beet pulp:water) ratio, containing calcium sulfate and carbonate. Strains belonging to different fungal species grew well in the growth medium finally selected, producing yields ranging from 50 to 500 g mycelium per kilogram of dry culture, after 22-27 days. Cultures containing up to 400 g beet pulp grew successfully, and could be scaled up. CONCLUSION: A solid culture medium based on beet pulp supported the growth of diverse taxa of fungal endophytes. Both the water and calcium salt content of the growth medium affected the efficiency of mycelium production. Considering these factors, beet pulp medium was an excellent endophyte cultivation medium because of the high yield of fungal biomass observed, together with its ease of handling and scaling-up production. © 2019 Society of Chemical Industry.


Assuntos
Beta vulgaris/microbiologia , Meios de Cultura/metabolismo , Endófitos/crescimento & desenvolvimento , Fungos/crescimento & desenvolvimento , Beta vulgaris/química , Biomassa , Meios de Cultura/química , Endófitos/metabolismo , Fermentação , Fungos/metabolismo , Micélio/crescimento & desenvolvimento , Micélio/metabolismo
16.
Crit Rev Biotechnol ; 40(1): 31-45, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31656090

RESUMO

Phytoremediation uses plants and associated microbes to remove pollutants from the environment and is considered a promising bioremediation method. Compared with well-described single contaminant treatments, the number of studies reporting phytoremediation of soil mixed pollutants has increased recently. Endophytes, including bacteria and fungi, exhibit beneficial traits for the promotion of plant growth, stress alleviation, and biodegradation. Moreover, endophytes either directly or indirectly assist host plants to survive high concentrations of organic and inorganic pollutants in the soil. Endophytic microorganisms can also regulate the plant metabolism in different ways, exhibiting a variety of physiological characteristics. This review summarizes the taxa and physiological properties of endophytic microorganisms that may participate in the detoxification of contaminant mixtures. Furthermore, potential biomolecules that may enhance endophyte mediated phytoremediation are discussed. The practical applications of pollutant-degrading endophytes and current strategies for applying this valuable bio-resource to soil phytoremediation are summarized.


Assuntos
Endófitos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Metais/metabolismo , Compostos Orgânicos/metabolismo
17.
J Appl Microbiol ; 129(2): 186-198, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31858682

RESUMO

In an agro-ecosystem, industrially produced nitrogenous fertilizers are the principal sources of nitrogen for plant growth; unfortunately these also serve as the leading sources of pollution. Hence, it becomes imperative to find pollution-free methods of providing nitrogen to crop plants. A diverse group of free-living, plant associative and symbiotic prokaryotes are able to perform biological nitrogen fixation (BNF). BNF is a two component process involving the nitrogen fixing diazotrophs and the host plant. Symbiotic nitrogen fixation is most efficient as it can fix nitrogen inside the nodule formed on the roots of the plant; delivering nitrogen directly to the host. However, most of the important crop plants are nonleguminous and are unable to form symbiotic associations. In this context, the plant associative and endophytic diazotrophs assume importance. BNF in nonlegumes can be encouraged either through the transfer of BNF traits from legumes or by elevating the nitrogen fixing capacity of the associative and endophytic diazotrophs. In this review we discuss mainly the microbiological strategies which may be used in nonleguminous crops for enhancement of BNF.


Assuntos
Produtos Agrícolas/microbiologia , Endófitos/metabolismo , Fixação de Nitrogênio , Fabaceae/microbiologia , Nódulos Radiculares de Plantas/microbiologia , Simbiose
18.
Molecules ; 24(24)2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31817301

RESUMO

The fungal strain Alternaria alternata JS0515 was isolated from Vitex rotundifolia (beach vitex). Twelve secondary metabolites, including one new altenusin derivative (1), were isolated. The isolated metabolites included seven known altenusin derivatives (2-8), two isochromanones (9, 10), one perylenequinone (11), and one benzocycloalkanone (12). Their structures were determined via 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), and computational electronic circular dichroism (ECD) analysis. Compounds 3 and 11 increased pyruvate dehydrogenase (PDH) activity in AD-293 human embryonic kidney cells and significantly inhibited PDH phosphorylation. The IC50 values of 3 and 11 were 32.58 and 27.82 µM, respectively.


Assuntos
Alternaria/isolamento & purificação , Alternaria/metabolismo , Endófitos/isolamento & purificação , Endófitos/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Metabolismo Secundário , Vitex/microbiologia , Alternaria/enzimologia , Bioensaio , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Endófitos/enzimologia , Espectroscopia de Prótons por Ressonância Magnética
19.
Mar Drugs ; 17(12)2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31756930

RESUMO

Four new xanthene derivatives, penicixanthenes A-D (1-4), and one known compound 5 were isolated from a marine mangrove endophytic fungus Penicillium sp. JY246 that was obtained from the stem of Ceriops tagal. Their structures were determined by detailed NMR, MS spectroscopic data, modified Mosher's method, and calculated electronic circular dichroism data. All of the isolated compounds were examined for insecticidal activity. Compounds 2 and 3 showed growth inhibition activity against newly hatched larvae of Helicoverpa armigera Hubner with the IC50 values 100 and 200 µg/mL, respectively, and compounds 1, 3, and 4 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with LC50 values of 38.5 (±1.16), 11.6 (±0.58), and 20.5 (±1) µg/mL, respectively. The four xanthene derivatives have the potential to be developed as new biopesticides.


Assuntos
Agentes de Controle Biológico/toxicidade , Endófitos/metabolismo , Penicillium/metabolismo , Xantenos/toxicidade , Animais , Agentes de Controle Biológico/isolamento & purificação , Agentes de Controle Biológico/metabolismo , Culex/efeitos dos fármacos , Concentração Inibidora 50 , Larva , Mariposas/efeitos dos fármacos , Rhizophoraceae/microbiologia , Áreas Alagadas , Xantenos/isolamento & purificação , Xantenos/metabolismo
20.
BMC Complement Altern Med ; 19(1): 330, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752824

RESUMO

BACKGROUND: Endophytic fungi are a proven source of bioactive secondary metabolites that may provide lead compounds for novel drug discovery. In this study, crude extracts from fungal endophytes isolated from Datura stramonium were evaluated for cytotoxic activity on two human cancer cell lines. METHODS: Fungal endophytes were isolated from surface sterilized aerial parts of D. stramonium and identified using molecular, morphological and phylogenetic methods. Ethyl acetate crude extracts from these isolates were evaluated for cytotoxic activity on A549 lung carcinoma and UMG87 glioblastoma cell lines. Metabolite profiling was then performed by liquid chromatography coupled to quadrupole time-of-flight with tandem mass spectrometry (LC-QTOF-MS/MS) for the cytotoxic crude extract. RESULTS: Eleven fungal endophytes were identified from D. stramonium. Significant cytotoxicity was only observed from the crude extract of Alternaria sp. KTDL7 on UMG87 glioblastoma cells (IC50 = 21.49 µg/ml). Metabolite profiling of this crude extract tentatively revealed the presence of the following secondary metabolites: 1,8-dihydroxynaphthalene (1), anserinone B (2), phelligridin B (3), metacytofilin (4), phomopsidin (5) and vermixocin A (6). Compounds 2 and 3 have been shown to be cytotoxic in literature. CONCLUSION: The findings in this study suggest that the crude extract of Alternaria sp. KTDL7 possesses compound(s) cytotoxic to glioblastoma multiforme cells. Future studies to isolate and characterize the cytotoxic compound(s) from this fungus could result in lead development of a fungal-based drug for glioblastoma multiforme treatment.


Assuntos
Antineoplásicos/farmacologia , Produtos Biológicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Datura stramonium/microbiologia , Células A549 , Antineoplásicos/química , Produtos Biológicos/química , Linhagem Celular Tumoral , Cromatografia Líquida , Endófitos/química , Endófitos/genética , Endófitos/metabolismo , Fungos/química , Fungos/genética , Fungos/metabolismo , Humanos , Espectrometria de Massas em Tandem
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