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Ergot is a fungal disease and causes reductions in seed productivity and quality. We aimed to identify promising genotypes of brachiaria evaluating: (1) seed production potential (number of tillers, racemes per inflorescence, spikelets per raceme, raceme length, weight and number of seeds, and germination) and (2) resistance of seeds to Ergot (infected tillers, infected seeds). Five genotypes of Brachiaria grasses, four non-natural hybrids named BH1619, BH1810, BH1516 and Mavuno Palisadegrass (Urochloa brizantha x Urochloa ruziziensis), and Marandu Palisadegrass (U. brizantha Hoechst cv. Marandu) were evaluated. The BH1619 hybrid, despite the high weight of seeds, produced less viable, pure seeds. The hybrid BH1516 had a lower percentage of flowered tillers (42%) and seeds infected with ergot (8%). Marandu Palisadegrass had a higher percentage of infected tillers (95%) and infected seeds (38%). The hybrid BH1516 was the most resistant to ergot, followed by Mavuno Palisadegras sand BH1619. Among all materials, Mavuno Palisadegrass and BH1516 have a higher potential for seed production due to the higher percentage of flowered tillers and production of pure seeds with high germination capacity. The BH1516 hybrid was resistant to ergot, making it a better choice for use in infected areas used for seed or forage production.(AU)

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BACKGROUND: The phytopatogen Claviceps paspali is the causal agent of Ergot disease in Paspalum spp., which includes highly productive forage grasses such as P. dilatatum. This disease impacts dairy and beef production by affecting seed quality and producing mycotoxins that can affect performance in feeding animals. The molecular basis of pathogenicity of C. paspali remains unknown, which makes it more difficult to find solutions for this problem. Secreted proteins are related to fungi virulence and can manipulate plant immunity acting on different subcellular localizations. Therefore, identifying and characterizing secreted proteins in phytopathogenic fungi will provide a better understanding of how they overcome host defense and cause disease. The aim of this work is to analyze the whole genome sequences of three C. paspali isolates to obtain a comparative genome characterization based on possible secreted proteins and pathogenicity factors present in their genome. In planta RNA-seq analysis at an early stage of the interaction of C. paspali with P. dilatatum stigmas was also conducted in order to determine possible secreted proteins expressed in the infection process. RESULTS: C. paspali isolates had compact genomes and secretome which accounted for 4.6-4.9% of the predicted proteomes. More than 50% of the predicted secretome had no homology to known proteins. RNA-Seq revealed that three protein-coding genes predicted as secreted have mayor expression changes during 1 dpi vs 4 dpi. Also, three of the first 10 highly expressed genes in both time points were predicted as effector-like. CAZyme-like proteins were found in the predicted secretome and the most abundant family could be associated to pectine degradation. Based on this, pectine could be a main component affected by the cell wall degrading enzymes of C. paspali. CONCLUSIONS: Based on predictions from DNA sequence and RNA-seq, unique probable secreted proteins and probable pathogenicity factors were identified in C. paspali isolates. This information opens new avenues in the study of the biology of this fungus and how it modulates the interaction with its host. Knowledge of the diversity of the secretome and putative pathogenicity genes should facilitate future research in disease management of Claviceps spp.

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Claviceps species affecting Paspalum spp. are a serious problem, as they infect forage grasses such as Paspalum dilatatum and P. plicatulum, producing the ergot disease. The ascomycete C. paspali is known to be the pathogen responsible for this disease in both grasses. This fungus produces alkaloids, including ergot alkaloids and indole-diterpenes, that have potent neurotropic activities in mammals. A total of 32 isolates from Uruguay were obtained from infected P. dilatatum and P. plicatulum. Isolates were phylogenetically identified using partial sequences of the genes coding for the second largest subunit of RNA polymerase subunit II (RPB2), translation elongation factor 1-α (TEF1), ß-tubulin (TUB2), and the nuc rDNA 28S subunit (28S). Isolates were also genotyped by randomly amplified polymorphic DNA (RAPD) and presence of genes within the ergot alkaloid (EAS) and indole-diterpene (IDT) biosynthetic gene clusters. This study represents the first genetic characterization of several isolates of C. paspali. The results from this study provide insight into the genetic and genotypic diversity of Claviceps paspali present in P. dilatatum and suggest that isolates from P. plicatulum could be considered an ecological subspecies or specialized variant of C. paspali. Some of these isolates show hypothetical alkaloid genotypes never reported before.

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Resumen El ergotismo es el resultado de la intoxicación con alcaloides derivados del ergot. Durante la edad media y hasta el siglo XIX fue el responsable de grandes epidemias en Europa por el consumo de granos contaminados con el cornezuelo del centeno provocando manifestaciones isquémicas características y afección del sistema nervioso. El ergotismo como se conoció en el Medioevo ha desaparecido, pero aún hoy en día se reportan casos en el marco de uso terapéutico de ergotamínicos. Se pretenden describir algunos de sus aspectos históricos y clínicos distintivos.

Abstract Ergotism is the result of intoxication with alkaloids derived from ergot. During the middle ages and until the nineteenth century it was responsible for major epidemics in Europe for the consumption of grains contaminated with ergot, causing characteristic ischemic manifestations and nervous system involvement. Ergotism as it was known in the Middle Ages has disappeared, but even today cases are reported in the therapeutic use of ergotamine. Some of its distinctive historical and clinical aspects are intended to be described.

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The Ascomycete fungus Claviceps gigantea infects maize kernels and synthetizes several alkaloids, mostly dihydrolysergamides. There is limited information on the damage these toxins cause in mammals, despite reports from infested areas with 90% presence of the fungus sclerotia. With this background, it was decided to determine the biological activity of chemical compounds present in sclerotia of C. gigantea in rabbits 38 days after weaning. Sclerotia of C. gigantea were collected in fields with high incidence of the disease, ground and analysed for nutrients. Experimental diets were prepared with four treatments, where sclerotial powder was added, substituting for alfalfa flour in increasing proportions [C. gigantea/alfalfa flour (0:100, 5:95, 15:85 and 25:75)]. Total ergot alkaloid content was analysed by high-performance liquid chromatography. Male juvenile rabbits were utilised and distributed in completely randomised design with four replications. Initial weight was recorded in each animal, and experimental diet was offered. In this study, weight of animals, feed consumption and feed conversion were evaluated in individual animals. Blood samples were taken for haemograms, and finally euthanasia was practiced. The consumption of C. gigantea had a negative effect on body weight and feed consumption. The necropsies showed anomalies proportional to the consumption of feed contaminated with the fungus.

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The ergot, genus Claviceps, comprises approximately 60 species of specialised ovarial grass parasites famous for the production of food toxins and pharmaceutics. Although the ergot has been known for centuries, its evolution have not been resolved yet. Our approach combining multilocus phylogeny, molecular dating and the study of ecological, morphological and metabolic features shows that Claviceps originated in South America in the Palaeocene on a common ancestor of BEP (subfamilies Bambusoideae, Ehrhartoideae, Pooideae) and PACMAD (subfamilies Panicoideae, Aristidoideae, Chloridoideae, Micrairoideae, Arundinoideae, Danthonioideae) grasses. Four clades described here as sections diverged during the Paleocene and Eocene. Since Claviceps are parasitic fungi with a close relationship with their host plants, their evolution is influenced by interactions with the new hosts, either by the spread to a new continent or the radiation of the host plants. Three of the sections possess very narrow host ranges and biogeographical distributions and have relatively low toxicity. On the contrary, the section Claviceps, comprising the rye ergot, C. purpurea, is unique in all aspects. Fungi in this section of North American origin have spread all over the world and infect grasses in all subfamilies as well as sedges, and it is the only section synthesising toxic ergopeptines and secalonic acids. The evolutionary success of the Claviceps section members can be explained by high toxin presence, serving as feeding deterrents and playing a role in their protective mutualism with host plants. Closely related taxa Neoclaviceps monostipa and Cepsiclava phalaridis were combined into the genus Aciculosporium.

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Sorghum ergot (caused by Claviceps africana) is a disease that affects sorghum seed development and yield. The interaction between pollen tube growth and hyphal development determines whether ovaries will be fertilized or colonized. Thus their respective deposition times on the stigma are critical. The effect of the time interval between pollination and inoculation on stigma receptivity and seed production was measured under field conditions in the male-sterile line A9 at Montecillo, State of México (2240m altitude). Pollination and inoculation treatments, from simultaneous application to 2 and 4h difference, were imposed when all stigmas on the panicle had emerged. Control panicles were either only pollinated or only inoculated. Eighteen hours later, pollen grains that adhered to, and germinated within the stigma, pollen tubes in the style and ovary, and fertilized pistils were counted. Pistils showing some disease expression (germinated spores, mycelium growth, or tissue necrosis) at 18, 48, and 72h were recorded. The number of diseased florets was registered at the dough growth stage, while number of seeds, grain yield and 100-seeds weight was measured at the physiological maturity. The pathogen applied in a water suspension of macro and secondary conidia caused a decrease in stigma receptivity; the greatest decrease (40-60%) occurred when the pollen and the inoculum were deposited almost simultaneously, regardless of which was deposited first. The route of the pollen tube was also the route for fungal infection. On average, treatments first inoculated had 60% more diseased florets and 36% less grain yield, 30% fewer seeds and seed size decreased 8%, than those first pollinated.

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The occurrence of the alditol oligosaccharides in the Claviceps afriana honeydew is partly as a rational expression of the pathogen's selective nutritive metabolism of the sucrose supplied by the host plant. The experiments were carried out in laboratory and when 14C-D-sucrose, 14C-D-fructose or 14C-D-mannitol radiolabelled saccharides were incorporated into: a) sorghum plant infected by C. africana, b) whole and macereted micelia tissue and c) cell-free honeydew of C. africana, it was observed that the glucose moiety of sucrose was not involved in oligosaccharides formation. Glucose was used by the pathogen as nutritional source. Part of the unused fructose moiety was reduced to mannitol by the pathogen's enzymes which was also excreted into honeydew where reductase activity accepted 14C mannitol. The mannitol was linked with fructose in a 2-position synthesizing the disaccharide 1-beta-D-fructofuranosyl-D-mannitol and then the process was repeated by the mannitol moiety of the disaccharide to yield the trisaccharide 1,6-di-beta-D-fructofuranosyl-D-mannitol, which became dominant. The direct formation of alditol saccharides from monosaccharides in this way seems to be unique to C. africana, contrasting with the fructosyl transfer from sucrose to sucrose which is usual in others ergot parasites.(AU)

A ocorrência de oligossacarídeos contendo alditol em exsudações da doença açucarada produzidos por Claviceps africana é em parte uma expressão racional do metabolismo seletivo de nutrição do patógeno na tansformação da sacarose fornecida pela planta. Quando açúcares radioativos marcados com 14C (D-sucrose, D-fructose e D-mannitol) foram incorporados em: a) planta do sorgo infectada por C. africana, b) tecido micelial inteiro e macerado isolado de C. africana e c) exsudato livre de células de C. africana, foi observado que a glicose da sacarose não estava envolvida na formação de oligossacarídeos, sendo usada pelo patógeno como fonte nutritiva. Parte da frutose não utilizada da sacarose foi reduzida a mannitol por enzimas do patógeno. As enzimas envolvidas também atuaram no exsudato da "doença açucarada", ativando a ação da redutase pela incorporação do 14C manitol. O manitol foi ligado na posição 2 da fructose, formando o dissacarídeo 1-beta-D-fructofuranosyl-D-mannitol e, posteriormente, adicionada mais uma fructose ao mannitol do dissacarídeo, formando o trisacarídeo 1,6-di-beta-D-fructofuranosyl-D-manitol, que se tornou predominate. A formação direta de oligossacarídeos contendo alditol a partir de monossacarídeos parece ser exclusiva em C. africana, contrastando com a ação enzimática da frutose transferase a partir de sucrose para sucrose, a qual é muito comum em outros patógenos tipo "ergot".(AU)

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Se debe evitar el uso de plantas con fines terapéuticos sin un adecuado control médico, sobre todo en el período gestacional. Se distinguen las plantas adecuadas para ser utilizadas durante el embarazo, y las que son peligrosas, especialmente el cornezuelo de centeno y sus derivados(AU)

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Se debe evitar el uso de plantas con fines terapéuticos sin un adecuado control médico, sobre todo en el período gestacional. Se distinguen las plantas adecuadas para ser utilizadas durante el embarazo, y las que son peligrosas, especialmente el cornezuelo de centeno y sus derivados(AU)

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