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1.
Zhongguo Zhong Yao Za Zhi ; 45(1): 65-71, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-32237412

RESUMO

The interaction of endophytes and host plant is an effective mean to regulate the growth and secondary metabolism of medicinal plants. Here we want to elucidate the effects and mechanism of Phoma herbarum D603 on the root development and tanshinone synthesis in root of Salvia miltiorrhiza by endophyte-plant coculture system. The mycelium of P. herbarum D603 was colonized in the root tissue space, and formed a stable symbiotic relationship with host plant. The in vitro activities analysis showed that the concentration of IAA produced by D603 can reach(6.45±0.23) µg·mL~(-1), and this strain had some abilities of phosphorus solubilization and siderophore production activities. The coculture experiment showed that strain D603 can significantly promote the synthesis and accumulation of tanshinones in the root of S. miltiorrhiza, in which after 8 weeks of treatment with D603, the content of tanshinone Ⅱ_A in the roots reached up to(1.42±0.59) mg·g~(-1). By the qRT-PCR analysis results, we found that D603 could improve the expression levels of some key genes(DXR, DXS, GGPP, HMGR, CPS) of tanshinone biosynthesis pathway in host plant S. miltiorrhiza, but the promoting effect mainly occurred in the early stage of the interaction, and the enzyme activity level decreased in varying degrees of the later stage. In summary, seed-associated endophyte P. herbarum D603 can promote the growth and root development of S. miltiorrhiza by producing hormones, promoting nutrient absorption and siderophore production, and promote the synthesis and accumulation of tanshinones by regulating the expression level of key genes in the synthetic pathway in S. miltiorrhiza.


Assuntos
Abietanos/biossíntese , Ascomicetos/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Salvia miltiorrhiza/microbiologia , Endófitos/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Salvia miltiorrhiza/metabolismo , Sementes/microbiologia
2.
Microbiol Res ; 236: 126436, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32179388

RESUMO

Trichoderma longibrachiatum EF5 is an endophytic fungal antagonist of rice. It is used for the control of soil-borne fungal pathogens-Sclerotium rolfsii and Macrophomina phaseolina. We demonstrate that T. longibrachiatum EF5 inhibits the growth of these pathogens on direct interaction as well as via the production of the microbial volatile organic compounds (mVOCs). The mVOCs reduced mycelial growth and inhibited the production of sclerotia by altering the mycelial structure. We profiled 138 mVOCs, when T. longibrachiatum EF5 interacted with the two pathogens. During these interactions, several compounds are up- or downregulated by T. longibrachiatum EF5, including longifolene, caryophyllene,1-Butanol 2-methyl, cedrene, and cuprenene. These compounds are involved in the biosynthetic pathways of the sesquiterpenoid and alkane, and the degradation pathway of trimethylamine. We provide an insight into the multiple modes by which T. longibrachiatum EF5 exerts antagonistic actions, such as hyperparasitism, competitions, and antibiosis via mVOCs. In contrast to their antimicrobial properties, these metabolites could also promote plant growth.


Assuntos
Agaricales/efeitos dos fármacos , Antibiose , Ascomicetos/efeitos dos fármacos , Trichoderma/metabolismo , Compostos Orgânicos Voláteis/farmacologia , Agaricales/crescimento & desenvolvimento , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico , Interações Microbianas , Doenças das Plantas/microbiologia , Microbiologia do Solo , Compostos Orgânicos Voláteis/química
3.
Int J Mol Sci ; 21(2)2020 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-31940908

RESUMO

Morchella crassipes (Vent.) Pers., a typical yellow morel species with high economic value, is mainly distributed in the low altitude plains of Eurasia. However, rare research has been performed on its genomics and polarity, thus limiting its research and development. Here, we reported a fine physical map of the nuclear genome at the subchromosomal-scale and the complete mitochondrial genome of M. crassipes. The complete size of the nuclear genome was 56.7 Mb, and 23 scaffolds were assembled, with eight of them being complete chromosomes. A total of 11,565 encoding proteins were predicted. The divergence time analysis showed that M. crassipes representing yellow morels differentiated with black morels at ~33.98 Mya (million years), with 150 gene families contracted and expanded in M. crassipes versus the two black morels (M. snyderi and M. importuna). Furthermore, 409 CAZYme genes were annotated in M. crassipes, containing almost all plant cell wall degrading enzymes compared with the mycorrhizal fungi (truffles). Genomic annotation of mating type loci and amplification of the mating genes in the monospore population was conducted, the results indicated that M. crassipes is a heterothallic fungus. Additionally, a complete circular mitochondrial genome of M. crassipes was assembled, the size reached as large as 531,195 bp. It can be observed that the strikingly large size was the biggest up till now, coupled with 14 core conserved mitochondrial protein-coding genes, two rRNAs, 31 tRNAs, 51 introns, and 412 ncORFs. The total length of intron sequences accounted for 53.67% of the mitochondrial genome, with 19 introns having a length over 5 kb. Particularly, 221 of 412 ncORFs were distributed within 51 introns, and the total length of the ncORFs sequence accounted for 40.83% of the mitochondrial genome, and 297 ncORFs had expression activity in the mycelium stage, suggesting their potential functions in M. crassipes. Meanwhile, there was a high degree of repetition (51.31%) in the mitochondria of M. crassipes. Thus, the large number of introns, ncORFs and internal repeat sequences may contribute jointly to the largest fungal mitochondrial genome to date. The fine physical maps of nuclear genome and mitochondrial genome obtained in this study will open a new door for better understanding of the mysterious species of M. crassipes.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Mapeamento Cromossômico/métodos , Sequenciamento Completo do Genoma/métodos , Ascomicetos/genética , Regulação Fúngica da Expressão Gênica , Tamanho do Genoma , Genoma Fúngico , Genoma Mitocondrial , Sequenciamento de Nucleotídeos em Larga Escala , Anotação de Sequência Molecular , Filogenia
4.
Food Microbiol ; 87: 103395, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948636

RESUMO

Volatile compounds produced by L1 and L8 strains were assayed against mycelia and conidia growth of Monilinia laxa, M. fructicola, M. polystroma, and M. fructigena of stone fruits. Results showed that volatile metabolites inhibited significantly pathogens growth, in particular M. fructigena mycelium growth (70% by L1 and 50% by L8) and M. fructicola conidia germination (85% by L1 and 70% by L8) compared to the control. Moreover, the antagonistic activity was enhanced by the addition of asparagine (120 mg L-1) in the culture media composition. Synthetic pure compounds were tested in vitro on pathogens mycelial and conidia growth and their EC50 values were estimated, confirming 2-phenethyl as the most active compound. For this reason 2-phenethyl and VOCs of both yeast strains were assayed in vivo on cherry, peach, and apricot fruits. Regarding peach fruit, both treatments, yeasts and pure compounds, displayed the best inhibiting action against all the pathogens especially against M. laxa (100% by L1, 84% by L8 and 2-phenethyl). ATR/IR spectroscopy analysis showed how VOCs produced by both strains increase the fruit waxes complexity reducing the pathogens attack so playing an essential role in the antagonistic activity of both yeast strains and on fruit structural composition.


Assuntos
Ascomicetos/química , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Compostos Orgânicos Voláteis/farmacologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Frutas/microbiologia , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Prunus persica/microbiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo
5.
Microbiol Res ; 231: 126353, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31707299

RESUMO

Cladosporium spp. is a cosmopolitan fungal genus. In the literature, it has been reported as a biological agent for controlling several plant diseases, but its mechanism of action has never been clarified. The present study aims to identify Cladosporium spp. based on the DNA phylogeny of nine isolates obtained from the phylloplane of rice and their potential antagonistic activity against the main fungal pathogens that affect rice crop. Nine isolates of Cladosporium spp. were identified based on DNA phylogeny, molecular and morphological characterization, and their antagonistic effects with the rice pathogens C. miyabeanus, M. oryzae, M. albescens and S. oryzae. Four isolates were selected to study lytic enzymes such as ß-1,3-glucanase, chitinase and protease, and only one isolate was selected for a conidial germination and appressoria formation assay. The nine isolates were identified as C. cladosporioides, C. tenuissimum and C. subuliforme. Four isolates, identified as C. cladosporioides, inhibited the mycelial growth of rice pathogens such as C1H (68.59%) of S. oryzae, C5 G (74.32%) of C. miyabeanus, C11 G (75.97%) of M. oryzae and C24 G (77.39%) of M. albescens. C24 G showed a high activity of lytic enzymes, was tested against C. miyabeanus and M. oryzae, and inhibited conidial germination and appressorium formation by more than 59.36%. The characterization of C. cladosporioides suggested this species as a potential bioagent for the management of several rice diseases, especially rice blast. This is the first time that a potential biological agent from the genus Cladosporium identified at the species level was isolated from the rice phylloplane, and some of its mechanisms of action were demonstrated, such as increasing lytic enzyme activity against rice pathogens.


Assuntos
Cladosporium , Folhas de Planta/microbiologia , Patologia Vegetal , Antibiose , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico , Quitinases/metabolismo , Cladosporium/enzimologia , Cladosporium/genética , Cladosporium/isolamento & purificação , DNA Ribossômico , Fungos não Classificados/crescimento & desenvolvimento , Glicosídeo Hidrolases/metabolismo , Magnaporthe/crescimento & desenvolvimento , Micoses , Oryza/microbiologia , Peptídeo Hidrolases/metabolismo , Filogenia , Doenças das Plantas
6.
Appl Biochem Biotechnol ; 190(1): 73-89, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31301009

RESUMO

Curvulamine, a novel scaffold alkaloid with remarkable selective antibacterial activity, is produced by marine fungus Curvularia sp. IFB-Z10. However, its deep pharmaceutical research and application are severely restricted by the low yield, which needs to be solved urgently. The purpose of this study was to improve curvulamine production via precursors co-addition strategy and further reveal the regulation mechanism. In this work, the optimal precursors co-addition conditions were firstly obtained, and curvulamine production achieved 166.74 mg/L with the supply of 250 mg/L alanine and 200 mg/L proline at 60 h, which was 4.08 times that of control. It was observed that under alanine and proline stimulation, fungus exhibited the morphology of a small-diameter compact pellet. Furthermore, the organic acid levels in central carbon metabolism (CCM) were declined with precursors supplement. Besides, precursors also induced the critical biosynthetic gene transcriptions. The above findings collectively promoted curvulamine synthesis. Finally, Curvularia sp. IFB-Z10 fermentation process was successfully established by feeding alanine and proline at 0.021 g/L/h and 0.017 g/L/h rate from 60 to 72 h, and curvulamine production reached 133.58 mg/L in a 5-L bioreactor. The information acquired would facilitate the enhancement of curvulamine yield in submerged fermentation and the research on synthesis regulation of other alkaloids.


Assuntos
Alcaloides/biossíntese , Ascomicetos/metabolismo , Aminoácidos/metabolismo , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Reatores Biológicos , Metabolismo dos Carboidratos , Divisão Celular , Fermentação , Genes Fúngicos , Nitrogênio/metabolismo , Transcrição Genética
7.
Plant Dis ; 104(1): 121-128, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31730414

RESUMO

Aureobasidium pullulans is used as a biocontrol agent for fire blight protection in organic apple and pear production. We assessed colonization of pome flowers by A. pullulans in orchards located near Corvallis, OR and Wenatchee, WA. Blossom Protect, a mix of A. pullulans strains CF10 and CF40, and its citrate-based companion, Buffer Protect, were sprayed at 70% bloom. Later in bloom, the population size of putative A. pullulans on flowers was estimated by dilution plating; plate scrapings of putative A. pullulans were then sampled and subjected to a PCR analysis. Sequenced PCR amplicons of the internal transcribed spacer region and the elongase gene confirmed the presence of A. pullulans, whereas a multiplex PCR with primers specific to CF10 and CF40 was used to determine the presence of the introduced strains. At Corvallis, a wet spring environment, A. pullulans, was recovered from most (>90%) Bartlett pear and Golden Delicious apple flowers sampled from experimental trees, regardless of whether the trees were treated with Blossom Protect. Nevertheless, population size estimates of A. pullulans on the flowers were correlated with the number of times Blossom Protect was sprayed on the trees. At Wenatchee, an arid spring environment, A. pullulans was detected on most flowers from trees treated with Blossom Protect, but only on a minority of flowers from nontreated controls. In both locations, the combined incidence of strains CF10 and CF40 on flowers averaged 89% on Blossom Protect-treated trees, but only 27% on adjacent, nontreated trees. During subsequent trials, the efficacy of Blossom Protect for fire blight control was compared with alternative yeast isolates, with each applied with Buffer Protect; local isolates of A. pullulans and Cryptococcus neoformans and a postharvest biocontrol strain of Cystofilobasidium infirmominiatum were used All yeast strains suppressed fire blight to a degree; however, in each of four trials, the level of suppression was highest with Blossom Protect, and it was significantly superior (P ≤ 0.05) to other yeast isolates in two of the trials. Because A. pullulans strains CF10 and CF40 were detected primarily on flowers on trees treated with Blossom Protect, and because they were detected much less frequently on nearby nontreated tress, we recommend treating every tree row with Blossom Protect at least once for organic fire blight suppression.


Assuntos
Ascomicetos , Frutas , Malus , Pyrus , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , DNA Fúngico/genética , Frutas/microbiologia , Malus/microbiologia , Interações Microbianas , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase , Pyrus/microbiologia
8.
Microbiol Res ; 231: 126369, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733598

RESUMO

The ability of endophytic fungi isolated from cucurbit plants to suppress soilborne diseases and the relationship between antagonism and disease suppression were studied. In dual culture tests of 1044 strains of 90 genera and three pathogenic fungi, 47.1 % of the endophytic fungal strains showed antagonistic effects on at least one pathogen; 186 strains against Rhizoctonia solani, 371 strains against Sclerotinia sclerotiorum, and 403 strains against Fusarium oxysporum f. sp. cucumerinum. The main antagonistic type of the strains of one genus generally was identical to one pathogen. In the pot experiment of cucumber inoculated with R. solani and endophytic fungi, 74.3 % and 33.3 % of 288 strains showed control efficacy of more than 50 % and more than 80 % on cucumber Rhizoctonia root rot respectively. These strains were mostly distributed in Fusarium, Chaetomium, Colletotrichum and Acrocalymma. There were some differences in the proportion of strains with better disease suppressive effects between strain sources. No significant correlation existed between the disease suppression of a strain in vivo and its antagonism against the pathogen in vitro. Most growth-promoting strains had good suppressive effects on cucumber Rhizoctonia root rot. In this study, 82 endophytic fungal strains had good disease suppressive effects and no obvious adverse effects on cucumber growth, and 35 of them showed obvious growth-promoting effects, which suggested that endophytic fungi from cucurbit plants have excellent potential for plant disease control.


Assuntos
Antibiose , Cucumis sativus/microbiologia , Endófitos/isolamento & purificação , Fungos/isolamento & purificação , Doenças das Plantas/microbiologia , Antifúngicos/isolamento & purificação , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico , Chaetomium/isolamento & purificação , Colletotrichum/isolamento & purificação , Fusarium/crescimento & desenvolvimento , Micoses , Rhizoctonia/crescimento & desenvolvimento , Microbiologia do Solo
9.
World J Microbiol Biotechnol ; 36(1): 7, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31845300

RESUMO

Orange juice is a major agricultural product, and oranges are among the most widely sold fresh fruits in several countries. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa, affects almost every species of citrus, causing a esthetic depreciation of the fruit and fruit drop, with consequent financial loss for its in natura commercialization. Fungicides are the major control measure for CBS, but have limited efficiency and high cost, and give rise to fungal strains resistant to these products. This work assayed the production of antifungal compounds by Bacillus spp. isolates and tested the potential of two isolates from B. subtilis (ACB-AP3 and ACB-83) for controlling CBS under field conditions with two previously untested orange varieties. A total of 15 isolates produced cell-free, thermostable or volatile compounds effective in suppressing P. citricarpa growth in vitro. It was possible to detect the production of two antibiotics (iturin and surfactin) by B. subtilis ACB-83. Additionally, B. subtilis isolates ACB-AP3 and ACB-83 displayed significant effects in controlling the disease under field conditions.


Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Ascomicetos/efeitos dos fármacos , Bacillus/isolamento & purificação , Bacillus/metabolismo , Citrus/microbiologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Frutas/microbiologia , Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Esporos Fúngicos
10.
BMC Genomics ; 20(1): 880, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31747891

RESUMO

BACKGROUND: Melatonin is a ubiquitous molecule and exists across kingdoms. Studies on melatonin in plants have mainly focused on its physiological influence on growth and development, and on its biosynthesis. A number of studies have been conducted on the melatonin content and exogenous melatonin treatment of grapevine (Vitis vinifera L.). However, key genes or enzymes of the melatonin biosynthetic pathway remain unclear. RESULTS: In this study, we cloned and identified the gene encoding serotonin N-acetyltransferase (SNAT) in grapevine (VvSNAT2). The VvSNAT2 protein was identified from a collection of 30 members of the grapevine GCN5-related N-acetyltransferase (GNAT) superfamily. Phylogenetic and protein sublocalization analyses showed that the candidate gene VvGNAT16 is VvSNAT2. Characterization of VvSNAT2 showed that its enzymatic activity is highest at a pH of 8.8 and a temperature of 45 °C. Analysis of enzyme kinetics showed the values of Km and Vmax of VvSNAT2 using serotonin were 392.5 µM and 836 pmol/min/mg protein, respectively. The expression of VvSNAT2 was induced by melatonin treatment and pathogen inoculation. Overexpression of VvSNAT2 in Arabidopsis resulted in greater accumulation of melatonin and chlorophyll and enhanced resistance to powdery mildew in the transgenic plants compared with the wild type (WT). Additionally, our data showed that the marker genes in the salicylic acid (SA) signaling pathway were expressed to higher levels in the transgenic plants compared with the WT. CONCLUSIONS: The VvSNAT2 gene was cloned and identified in grapevine for the first time. Our results indicate that VvSNAT2 overexpression activates the SA and JA signaling pathways; however, the SA pathway plays a central role in VvSNAT2-mediated plant defense.


Assuntos
Arilalquilamina N-Acetiltransferase/genética , Regulação da Expressão Gênica de Plantas , Melatonina/biossíntese , Doenças das Plantas/genética , Proteínas de Plantas/genética , Vitis/genética , Arabidopsis/enzimologia , Arabidopsis/genética , Arabidopsis/imunologia , Arilalquilamina N-Acetiltransferase/imunologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Clorofila/biossíntese , Clonagem Molecular , Ciclopentanos/metabolismo , Expressão Gênica , Oxilipinas/metabolismo , Filogenia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/imunologia , Plantas Geneticamente Modificadas , Plasmídeos/química , Plasmídeos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Ácido Salicílico/metabolismo , Serotonina/metabolismo , Transdução de Sinais , Vitis/classificação , Vitis/enzimologia , Vitis/imunologia
11.
J Food Sci ; 84(12): 3418-3428, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31762032

RESUMO

In order to study the effect of volatile organic compounds (VOCs) produced by Bacillus subtilis CF-3 combined with heat treatment on Monilinia fructicola in peach and Colletotrichum gloeosporioides in litchi fruit, fruits were treated with B. subtilis CF-3 VOCs and hot air alone or in combination. The quality indexes of peach and litchi fruit after treatment and the changes in defense-related enzymes were measured. The results showed that the B. subtilis CF-3 VOCs combined with heat treatment could significantly reduce the rot index of peach and litchi fruit, and effectively maintain firmness and soluble solids content, as well as reduce weight loss of fruits. The combined treatment effectively enhanced the activity of peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and superoxide dismutase (SOD) than either treatment alone, and enhanced the resistance of fruit to pathogenic fungi by activating disease-resistant enzymes (phenylalanine ammonia-lyase [PAL], chitinase [CHI], ß-1, 3-glucanase [GLU]) activity. In this study, B. subtilis CF-3 VOCs combined with heat treatment maintained the quality and delayed the decline of peach and litchi fruit, providing a theoretical basis for future applications. PRACTICAL APPLICATION: The combination of B. subtilis CF-3 VOCs and heat treatment reduce the extent of M. fructicola and C. gloeosporioides. The combination maintain the quality of peach and litchi better. The combination obviously improve the activity of defense-related enzyme in fruit.


Assuntos
Ascomicetos/efeitos dos fármacos , Bacillus subtilis/química , Colletotrichum/efeitos dos fármacos , Conservação de Alimentos/métodos , Litchi/microbiologia , Doenças das Plantas/microbiologia , Prunus persica/microbiologia , Compostos Orgânicos Voláteis/farmacologia , Ascomicetos/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Catecol Oxidase/metabolismo , Quitinases/metabolismo , Colletotrichum/crescimento & desenvolvimento , Frutas/enzimologia , Frutas/microbiologia , Temperatura Alta , Litchi/enzimologia , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/metabolismo , Prunus persica/enzimologia , Compostos Orgânicos Voláteis/metabolismo
12.
J Agric Food Chem ; 67(47): 13061-13072, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31738551

RESUMO

In this study, we purified three new sesquiterpenyl epoxy-cyclohexenoid (SEC) analogues, arthrobotrisin D (11) and its two derivatives, from nematode-trapping fungus Arthrobotrys oligospora. Our results revealed that arthrobotrisin type SEC metabolites could be detected in all the test fungal strains from geographically distinct regions grown on different nutrient media, indicative of unique diagnostic character as chemical indicators for A. oligospora. The time course designs over short-term intervals of the fungus under direct contact and indirect contact with living or dead nematodes revealed that arthrobotrisin B and D (6 and 11) displayed significant relationships (positive or negative correlation) with fungal saprophytic and pathogenic stages during a nematode predation event. Interestingly, fungus on nutrient-limiting medium conducive to fungal trap formation could rapidly drop the concentration levels of arthrobotrisins B and D within 6 h when dead nematodes were around, in great contrast to that for living nematodes. Moreover, only in the fungal strain under direct contact with living dominant soil bacteria, arthrobotrisins B and D exhibited significant increase in amounts. Among them, the new SEC, arthrobotrisin D (11) was found to be a key unique metabolic signal for fungal colony growth and fungal interaction with prey and bacteria. Our study suggested that chemical analysis of SEC metabolites in A. oligospora provides a window into the fungal growth status and much valuable information about ecological environments associated with the nematode infections.


Assuntos
Ascomicetos/química , Compostos de Epóxi/química , Nematoides/microbiologia , Sesquiterpenos/química , Animais , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Compostos de Epóxi/metabolismo , Estrutura Molecular , Sesquiterpenos/metabolismo
13.
J Agric Food Chem ; 67(43): 11877-11882, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31597038

RESUMO

The investigation of the metabolites from different cocultures of Nigrospora oryzae and Irpex lacteus in solid medium revealed two new squalenes (1 and 2); one new azaphilone (3); two new tremulane sesquiterpenes (4 and 5); and three known compounds, conocenol B (6), conocenol C (7), and 4-(4-dihydroxymethylphenoxy)benzaldehyde (8). The antagonistic relationship was examined by studying metabolite production. The production of compounds 6 and 8 by I. lacteus after the induction of coculture indicated significant selectivity for antifungal activity against phytopathogenic N. oryzae, with MICs of 16 µg/mL; compounds 6 and 8 also exhibited antifungal activities in vivo against Cerasus cerasoides infected by N. oryzae at concentrations of 100 µg/mL. New compounds 2 and 4 showed antifungal activities against Colletotrichum gloeosporioides, with MICs of 8 µg/mL, and compound 4 showed antifungal activity against Didymella glomerata with an MIC of 1 µg/mL. These results indicate that the mutually antagonistic relationship in the coculture of the phytopathogen and the endophyte can result in antibiotics that inhibit the phytopathogen and downregulate the production of phytotoxins by phytopathogenic N. oryzae. New compound 5 from I. lacteus showed weak activity against acetylcholinesterase (AChE), with an inhibition ratio of 16% at a concentration of 50 µM.


Assuntos
Antifúngicos/metabolismo , Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/metabolismo , Polyporales/metabolismo , Esqualeno/metabolismo , Antifúngicos/química , Antifúngicos/farmacologia , Ascomicetos/crescimento & desenvolvimento , Técnicas de Cocultura , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Fermentação , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Polyporales/química , Polyporales/crescimento & desenvolvimento , Prunus/microbiologia , Esqualeno/química , Esqualeno/farmacologia
14.
Int J Mol Sci ; 20(21)2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31652999

RESUMO

Many plant endophytes produce mycotoxins, but how host genetic variation influences endophyte colonization and mycotoxin production under natural conditions is poorly understood. This interaction has not been fully considered in many previous studies which used controlled experiments with agronomic or model plant species. Here, we investigated this interaction in a naturally occurring forb (a locoweed species) Oxytropis ochrocephala, its symbiotic endophyte Alternaria oxytropis, and the mycotoxin swainsonine. Host genetic variation was characterized by microsatellite markers. Endophyte infection rate and swainsonine levels were determined by PCR and HPLC, respectively. Genetic markers defined two distinct host populations and revealed that host genetics were significantly correlated with geographical location, elevation, and precipitation. As the host diverged, symbiotic interactions were reduced or failed to produce detectable swainsonine in one host population. Host genotype and precipitation had a significant impact in shaping swainsonine production at the population level. This study highlights the effect of host genotype in influencing this interaction in locoweeds.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Astrágalo (Planta)/microbiologia , Micotoxinas/biossíntese , Simbiose , Ascomicetos/metabolismo , Astrágalo (Planta)/genética , Cromatografia Líquida de Alta Pressão , Variação Genética , Genótipo , Repetições de Microssatélites/genética , Micotoxinas/análise , Swainsonina/análise , Swainsonina/metabolismo
15.
World J Microbiol Biotechnol ; 35(10): 150, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31549229

RESUMO

This study aimed to characterize a powerful antifungal component from bacteria. Bacillus subtilis strain XB-1, which showed maximal inhibition of Monilinia fructicola, was isolated and identified, and an antifungal protein was obtained from it. Ammonium sulfate precipitation, ion exchange chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to purify and identify the proteins secreted by B. subtilis XB-1. Analyses revealed that purified fraction V had the strongest antifungal effect, with the largest pathogen inhibition zone diameter of 4.15 cm after 4 days (P < 0.05). This fraction showed a single band with a molecular weight of approximately 43 kDa in SDS-PAGE. Results from SDS-PAGE and liquid chromatography electrospray ionization tandem mass spectrometry analyses demonstrated that fraction V was likely a member of the chitosanase family. These results suggest that B. subtilis XB-1 and its antifungal protein may be useful in potential biocontrol applications.


Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Bacillus subtilis/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/farmacologia , Glicosídeo Hidrolases/isolamento & purificação , Glicosídeo Hidrolases/farmacologia , Antifúngicos/química , Ascomicetos/efeitos dos fármacos , Ascomicetos/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Proteínas de Bactérias/química , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Glicosídeo Hidrolases/química , Peso Molecular
16.
Fungal Biol ; 123(10): 763-772, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31542193

RESUMO

Septoria tritici blotch (STB) caused by the heterothallic ascomycete Zymoseptoria tritici is currently one of the most devastating diseases of wheat worldwide. The extent of sexual reproduction of this pathogen is well documented on bread wheat, but not on durum wheat. The objective of the present study was to quantify the occurrence of Z. tritici sexual reproduction on durum wheat in the Tunisian environment. The assessment was undertaken using a triple approach combining fruiting body assessment, ascospore trapping and population genetic analyses. The results highlighted the formation of pseudothecia on leaves and stubble from the autumn until the end of the growing season. Likewise, qPCR monitoring highlighted a constant release of Z. tritici airborne inoculum during the wheat-growing season, with a peak of production at the end of the season. Genetic investigations using microsatellites revealed high levels of gene and genotypic diversities, an equal distribution of mating types, and a lack of genetic clustering within and between growing seasons. Taken together, these findings indicate that Z. tritici undergoes sexual reproduction on durum wheat in Tunisia at least to the same extent than on bread wheat in Western Europe, and that the dry and warm climate does not affect the mating process of the fungus. Frequent occurrence of sexual reproduction is a valuable knowledge to take into account in STB control strategies on durum wheat.


Assuntos
Ascomicetos/fisiologia , Carpóforos/crescimento & desenvolvimento , Variação Genética , Doenças das Plantas/microbiologia , Triticum/microbiologia , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Clima , Carpóforos/genética , Genótipo , Repetições de Microssatélites , Reprodução , Esporos Fúngicos , Tunísia
17.
Mycopathologia ; 184(5): 625-636, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31529298

RESUMO

Pseudogymnoascus destructans is the causative agent of a fungal infection of bats known as white-nose syndrome (WNS). Since its discovery in 2006, it has been responsible for precipitous declines of several species of cave-dwelling North American bats. While numerous advancements in the understanding of the disease processes underlying WNS have been made in recent years, there are still many aspects of WNS, particularly with respect to pathogen virulence, that remain unknown. In this preliminary investigation, we sought to further elucidate the disease cycle by concentrating on the pathogen, with specific focus on its ability to utilize lipids that compose bat wing sebum and are found in wing membranes, as a substrate for energy and growth. In vitro growth experiments were conducted with the three most common fatty acids that comprise bat sebum: oleic, palmitic, and stearic acids. None of the fatty acids were observed to contribute a significant difference in mean growth from controls grown on SDA, although morphological differences were observed in several instances. Additionally, as an accompaniment to the growth experiments, bat wing explants from Perimyotis subflavus and Eptesicus fuscus were fluorescently stained to visualize the difference in distribution of 16- and 18-carbon chain fatty acids in the wing membrane. Which substrates contribute to the growth of P. destructans is important to understanding the progressive impact P. destructans has on bat health through the course of the disease cycle.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Ácidos Graxos/metabolismo , Lipólise , Sebo/química , Animais , Quirópteros , Feminino , Masculino , Sebo/microbiologia , Asas de Animais/química , Asas de Animais/microbiologia
18.
Pestic Biochem Physiol ; 160: 70-78, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31519259

RESUMO

Sclerotinia sclerotiorum, which can cause Sclerotinia stem rot, is a devastating plant pathogen. This study aimed to assess the potential of pydiflumetofen, a new-generation succinate dehydrogenase inhibitor (SDHI) fungicide, to control Sclerotinia stem rot. Pydiflumetofen exhibited favorable bioactivity in suppressing mycelial growth, sclerotial production and morphological changes, and the myceliogenic and carpogenic germination of sclerotia. Treatment with pydiflumetofen increased the cell membrane permeability of S. sclerotiorum and decreased oxalic acid production. In addition, inoculation tests demonstrated that the protective activity of 40 µg/mL pydiflumetofen against the fungus was better than its curative activity. Under natural infection conditions, the spraying of pydiflumetofen at 200 g a.i. ha-1 significantly reduced the incidence and severity of Sclerotinia stem rot. In addition, the sensitivity baseline to pydiflumetofen was established using 171 isolates collected from various crops in China. The results showed that the frequency distribution of the EC50 values of pydiflumetofen was a unimodal curve with a mean EC50 value of 0.0095 ±â€¯0.0005 µg/mL. This study confirmed the favorable bioactivity of pydiflumetofen against S. sclerotiorum at various developmental stages and its high effectiveness under natural infection conditions, which indicates that pydiflumetofen is a promising tool for the management of Sclerotinia stem rot.


Assuntos
Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Pirazóis/farmacologia , Succinato Desidrogenase/antagonistas & inibidores , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Ácido Oxálico/metabolismo
19.
Molecules ; 24(18)2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31540346

RESUMO

The development of natural essential oil as an alternative to synthetic chemicals in the control of postharvest decay is currently in the spotlight. In the present study, the efficacy of seven essential oils in suppressing Collelotrichum gloeosporioides identified from sweet cherry was evaluated in vitro and clove oil was proved to be the most promising inhibitor. Thus, the antifungal properties and potential mechanisms of clove oil in vitro and in vivo by fumigation and contact treatments were intensively investigated. For C. gloeosporioides, the minimal inhibitory concentrations (MIC) of clove oil in air and contact phase were 80 and 300 µL/L in vitro testing, respectively. Based on the radial growth of C. gloeosporioides mycelium in medium, the fumgitoxic ability of essential oil was observed in a dose-dependent manner, which was not as dramatic as that under in vivo conditions. Furthermore, scanning electron microscopy and transmission electron microscopy of C. gloeosporioides exposed to clove oil exhibited obviously deleterious morphological and ultrastructural alterations confirming the disruption of fungal cell wall and endomembrane system, which resulted in increasing in permeability and causing the loss of intracellular constituents. In future, essential oils, combined with nano-emulsification approaches, could be good candidates as safe and effective antifungal agents for fungal spoilage of fresh commodities.


Assuntos
Antifúngicos/farmacologia , Ascomicetos/crescimento & desenvolvimento , Óleo de Cravo/farmacologia , Óleos Voláteis/farmacologia , Syzygium/química , Antifúngicos/química , Óleo de Cravo/química , Óleos Voláteis/química
20.
Microbiol Res ; 229: 126326, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31493702

RESUMO

Sclerotinia sclerotiorum (Lib.) de Bary produces a resistance structure called sclerotium, which guarantees its survival in soil for long periods. Morphological and melanization aspects during sclerotial development were evaluated by microscopy and qRT-PCR techniques. S. sclerotiorum produces sclerotia with different phases of maturation and melanization during growth in PDA medium. Using scanning electron microscopy we observed that there are no structural differences in the three stages of formation of melanized and non-melanized sclerotium. Through histochemical analysis we observed that the melanized sclerotium accumulates more glycogen and produces less protein than non-melanized sclerotia. Melanin was most commonly found in the rind of melanized sclerotia, and the highest concentration of lipofucsins was found in non-melanized sclerotia. These molecules are products of the lipid peroxidation pathway and are associated with oxidative stress during differentiation in fungi. The expression of histidine kinase (shk) and adenylate cyclase (sac) genes in melanized and non-melanized sclerotiawere also evaluated. The higher gene expression of shk and lesser expression of sac in non-melanized sclerotiais an indication of the participation of cell signaling in the development of these structures. The higher expression of polyketide synthase (pks), tyrosinase (tyr) and laccase (lac) in non-melanized sclerotia suggested that S. sclerotiorum can use the DHN and L-dopa pathways to produce melanin. Expression studies of the enzymes chitin synthase and glucan synthase suggest that this process occurs along with the formation of melanin. This is interesting since polysaccharides, such as chitin and ß-1,3-glucan, serve as a scaffold to which the melanin granules are cross-linked.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Ascomicetos/fisiologia , Doenças das Plantas/microbiologia , Ascomicetos/genética , Ascomicetos/patogenicidade , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Melaninas/metabolismo , Estresse Oxidativo , Phaseolus/microbiologia
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