RESUMO
The fungus Moniliophthora perniciosa secretes protein effectors that manipulate the physiology of the host plant, but few effectors of this fungus have had their functions confirmed. We performed functional characterization of a promising candidate effector of M. perniciosa. The inoculation of rBASIDIN at 4 µmol L-1 in the mesophyll of leaflets of Solanum lycopersicum caused symptoms of shriveling within 6 h without the presence of necrosis. However, when sprayed on the plant at a concentration of 11 µmol L-1, it caused wilting symptoms only 2 h after application, followed by necrosis and cell death at 48 h. rBASIDIN applied to Theobroma cacao leaves at the same concentration caused milder symptoms. rBASIDIN caused hydrogen peroxide production in leaf tissue, damaging the leaf membrane and negatively affecting the photosynthetic rate of Solanum lycopersicum plants. Phylogenetic analysis indicated that BASIDIN has orthologs in other phytopathogenic basidiomycetes. Analysis of the transcripts revealed that BASIDIN and its orthologs are expressed in different fungal species, suggesting that this protein is differentially regulated in these basidiomycetes. Therefore, the results of applying BASIDIN allow the inference that it is an effector of the fungus M. perniciosa, with a strong potential to interfere in the defense system of the host plant.
Assuntos
Agaricales , Basidiomycota , Cacau , Cytisus , Cacau/microbiologia , Filogenia , Agaricales/metabolismo , Basidiomycota/genética , Necrose , Doenças das Plantas/microbiologiaRESUMO
Alzheimer's disease (AD) is a neurodegenerative pathology, which is characterized by progressive and irreversible cognitive impairment. Most of the neuronal perturbations described in AD can be associated with soluble amyloid- ß oligomers (SO-Aß). There is a large amount of evidence demonstrating the neuroprotective effect of Nicotine neurotransmission in AD, mainly through nicotinic acetylcholine receptor (nAChR) activation and antiapoptotic PI3K/Akt/Bcl-2 pathway signaling. Using HPLC and GC/MS, we isolated and characterized two alkaloids obtained from C. scoparius, Lupanine (Lup), and 17- oxo-sparteine (17- ox), and examined their neuroprotective properties in a cellular model of SO-Aß toxicity. Our results showed that Lup and 17- ox (both at 0.03µM) prevented SO-Aß-induced toxicity in PC12 cells (Lup: 64±7%; 17- ox: 57±6%). Similar results were seen in hippocampal neurons where these alkaloids prevented SO-Aß neurotoxicity (Lup: 57±2%; 17- ox: 52±3%) and increased the frequency of spontaneous calcium transients (Lup: 60±4%; 17- Ox: 40±3%), suggesting an enhancing effect on neural network activity and synaptic activity potentiation. All of the neuroprotective effects elicited by both alkaloids were completely blocked by α-bungarotoxin. Additionally, we observed that the presence of both Lup and 17- ox increased Akt phosphorylation levels (52±4% and 35±7%, respectively) in cells treated with SO-Aß (3âh). Taken together, our results suggest that the activation of nAChR by Lup and 17- ox induces neuroprotection in different cellular models, and appears to be an interesting target for the development of new pharmacological tools and strategies against AD.
Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/toxicidade , Cytisus/química , Fármacos Neuroprotetores/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Esparteína/análogos & derivados , Esparteína/farmacologia , Animais , Sinalização do Cálcio/efeitos dos fármacos , Células HEK293 , Hipocampo/patologia , Humanos , Camundongos Endogâmicos C57BL , Rede Nervosa/efeitos dos fármacos , Neurônios/patologia , Proteína Oncogênica v-akt/metabolismo , Células PC12 , Ratos , Esparteína/química , Esparteína/isolamento & purificação , Sinapses/efeitos dos fármacosRESUMO
BACKGROUND: Moniliophthora perniciosa is a phytopathogenic fungus responsible for witches' broom disease of cacao trees (Theobroma cacao L.). Understanding the molecular events during germination of the pathogen may enable the development of strategies for disease control in these economically important plants. In this study, we determined a comparative proteomic profile of M. perniciosa basidiospores during germination by two-dimensional SDS-PAGE and mass spectrometry. RESULTS: A total of 316 proteins were identified. Molecular changes during the development of the germinative tube were identified by a hierarchical clustering analysis based on the differential accumulation of proteins. Proteins associated with fungal filamentation, such as septin and kinesin, were detected only 4 h after germination (hag). A transcription factor related to biosynthesis of the secondary metabolite fumagillin, which can form hybrids with polyketides, was induced 2 hag, and polyketide synthase was observed 4 hag. The accumulation of ATP synthase, binding immunoglobulin protein (BiP), and catalase was validated by western blotting. CONCLUSIONS: In this study, we showed variations in protein expression during the early germination stages of fungus M. perniciosa. Proteins associated with fungal filamentation, and consequently with virulence, were detected in basidiospores 4 hag., for example, septin and kinesin. We discuss these results and propose a model of the germination of fungus M. perniciosa. This research can help elucidate the mechanisms underlying basic processes of host invasion and to develop strategies for control of the disease.
Assuntos
Agaricales/genética , Agaricales/metabolismo , Cacau/microbiologia , Cytisus/metabolismo , Germinação/genética , Doenças das Plantas/microbiologia , Proteômica , Agaricales/patogenicidade , Catalase/metabolismo , Análise por Conglomerados , Cicloexanos/metabolismo , Cytisus/microbiologia , Ácidos Graxos Insaturados/metabolismo , Proteínas Fúngicas/genética , Germinação/fisiologia , Policetídeo Sintases/metabolismo , Policetídeos/metabolismo , Metabolismo Secundário , Alinhamento de Sequência , Sesquiterpenos/metabolismo , Esporos Fúngicos/metabolismo , Fatores de Transcrição , VirulênciaRESUMO
The occurrence of Scotch broom Cytisus scoparius (L.) Link (Fabaceae), is reported for the first time in Brazil. The species has been registered in the species-rich Campos Sulinos grasslands, in the Campos de Cima da Serra, and in the Serra do Sudeste. Naturalizing populations were frequently formed in natural habitats near to human settlements, where prevailing land uses and disturbances facilitate dispersal and establishment. The plant is an invasive species that has globally caused significant damage to biodiversity and economic losses. In Brazil, the species has a strong potential for spreading into a wide range of ecosystems. The Atlantic Forest biome and part of the Pampa biome, together known as the Campos Sulinos, represent optimal areas for the species. Features of the observed populations and recommendations for management are presented.
Assuntos
Cytisus/crescimento & desenvolvimento , Espécies Introduzidas , Brasil , Cytisus/classificação , FlorestasRESUMO
Erigeron sp. plants showing symptoms of witches' broom and stunting were found near orchards of passion fruit in São Paulo state, Brazil. These symptoms were indicative of infection by phytoplasmas. Thus, the aim of this study was to detect and identify possible phytoplasmas associated with diseased plants. Total DNA was extracted from symptomatic and asymptomatic plants and used in nested PCR conducted with the primer pairs P1/Tint and R16F2n/16R2. Amplification of genomic fragments of 1.2âkb from the 16S rRNA gene confirmed the presence of phytoplasma in all symptomatic samples. The sequence identity scores between the 16S rRNA gene of the phytoplasma strain identified in the current study and those of previously reported 'Candidatus Phytoplasma fraxini'-related strains ranged from 98% to 99% indicating the phytoplasma to be a strain affiliated with 'Candidatus Phytoplasma fraxini'. The results from a phylogenetic analysis and virtual RFLP analysis of the 16S rRNA gene sequence with 17 restriction enzymes revealed that the phytoplasma strain belongs to the ash yellows phytoplasma group (16SrVII); the similarity coefficient of RFLP patterns further suggested that the phytoplasma represents a novel subgroup, designated 16SrVII-D. The representative of this new subgroup was named EboWB phytoplasma (Erigeron bonariensis Witches' Broom).
Assuntos
Cytisus , Erigeron/microbiologia , Filogenia , Phytoplasma/classificação , Doenças das Plantas/microbiologia , Brasil , DNA Bacteriano/genética , Dados de Sequência Molecular , Phytoplasma/genética , Phytoplasma/isolamento & purificação , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Los cercos vivos urbanos tienen un rol significativo por ser reservorios de biodiversidad y por las funciones socioeconómicas que pueden sustentar. En Bariloche (Río Negro, Patagonia Argentina) se estudiaron 300 cercos familiares, la riqueza de especies leñosas componentes, sus usos medicinales y comestibles, presencia de aromaticidad, como así también su disponibilidad en comercios locales. Los cercos se componen de 86 especies, entre estas las más frecuentes son las exóticas: Cytisus scoparius, Pseudotsuga menziesii, Cupressus macrocarpa y Rosa sp., y las nativas: Chusquea culeou y Nothofagus antarctica. El 73% de las especies son medicinales, el 59% comestibles y el 33% aromáticas. Solo el 24% de las especies están disponibles en comercios de la ciudad dedicados a la venta de alimentos y/o productos herbolarios. Se concluye que los cercos de Bariloche tienen un alto potencial para la complementación, diversificación de la dieta y el tratamiento de dolencias menores de los pobladores locales.