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a b s t r a c tCeratocystis fimbriata Ellis & Halsted recently was recorded causing seed and seedling blight on Carapa guianensis Aubl. (andiroba), a tree species native to the Amazon Rainforest and prized for its valuable timber and medicinal seed oil. C. fimbriata more commonly causes wilt type diseases in woody hosts, especially on non-native host trees. However, on andiroba the disease occurs on seedlings and seeds, affecting the species regeneration. We studied 73 isolates of C. fimbriata on andiroba from three regions of the Amazon Basin to see if they represented natural or introduced populations. Analysis of ITS rDNA sequences and phylogenetic analysis of mating type genes revealed new haplotypes of C. fimbriata from the Latin American Clade that were closely related to other Brazilian populations of the fungus. In mating experiments, andiroba isolates were inter-fertile with tester strains of C. fimbriata from Brazil and elsewhere, confirming that they belong to a single biological species. Using microsatellite markers, 14 genotypes and populations with intermediate levels of genetic variability were found, suggesting that the fungus is indigenous to the Amazon Basin. Inoculation tests indicated that the andiroba isolates are host-specialized on andiroba, supporting the proposition of the special form C. fimbriata f. sp. carapa.

ResumoEste trabalho teve como objetivo elucidar, por meio da pirólise analítica acoplada à cromatografia gasosa e espectrometria de massa, alterações na composição química da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou não com silício (Si) e infectadas por Rhizoctonia solani. A concentração de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg -1 ) em comparação com as plantas não supridas (0,45 dag kg -1 ). Na presença de Si, a área abaixo da curva do progresso da queima das bainhas foi significativamente reduzida em 19 e 25%, respectivamente, para as plantas das cultivares BR-Irga-409 e Labelle em relação à ausência desse elemento na solução nutritiva. Com base nos espectros de massas obtidos, foram identificados 33 compostos, dos quais 10 foram produtos da degradação de carboidratos e 23 derivados da lignina. Dentre os derivados da lignina, oito compostos eram do tipo p-hidroxifenila, 11 compostos do tipo guaiacila e quatro compostos do tipo siringila. Nas bainhas das plantas das duas cultivares de arroz, supridas ou não com Si, a concentração de lignina (p-hidroxifenila, siringila (S) e guaiacila (G)) foi de, aproximadamente, 15%. Houve aumento na relação S/G apenas nas bainhas das plantas da cultivar BR-Irga 409 supridas com Si e infectadas por R. solani. A maior concentração de Si nas bainhas das plantas de arroz das duas cultivares, que por sua vez resultou em aumento na relação S/G, contribuiu para reduzir os sintomas da queima das bainhas.Palavras-chave: queima das bainhas, lignina, metabólitos secundários, resistência. Silicon altering compounds derived from the pyrolyses of leaf sheaths of rice plants infected with Rhizoctonia solani AbstractThis study elucidated, through analytical pyrolysis coupled to gas chromatography and mass spectrometry, changes in the chemical composition of lignin on leaf sheaths of rice plants of cultivars BR-Irga 409 and Labelle supplied or non-supplied with silicon (Si) and infected with Rhizoctonia solani. The Si concentration on leaf sheaths of plants supplied with this element was significatively higher (2.7 dag kg ). In the presence of Si, the area under leaf sheath blight progress curve was significantly reduced by 19 and 25% for plants from cultivars BR-Irga 409 and Labelle, respectively, in comparison to the absence of Si. Based on the mass spectra obtained, 33 compounds were identified, 10 of which were products from the degradation of carbohydrates and 23 derivate from lignin. From lignin derivatives, eight compounds were p-hydroxiphenil type, eleven compounds were guaiacyl type and four compounds were syringyl type. On leaf sheaths of both cultivars, the concentration of lignin (p-hydroxiphenil, syringyl (S) and guaiacyl (G)) was around 15%, regardless of Si. There was no increase in the S/G ratio only for the leaf sheaths of BR-Irga 409 supplied with Si and infected with R. solani. High Si concentration on leaf sheaths of both cultivars, which in turn resulted in an increase...

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Diagnosticou-se o perfil dos consumidores de supermercados em Pato Branco (PR), com relação às suas preferências pelas plantas medicinais e condimentares, como subsídio à produção por pequenos produtores rurais. Os consumidores preferem produtos orgânicos, observam a aparência e o preço do produto, e vão ao mercado uma vez por semana, preferencialmente aos sábados. As dez plantas medicinais preferidas, em ordem decrescente, são camomila, anis, boldo, carqueja, guaco, malva, poejo, espinheira-santa, menta e sálvia. As dez plantas condimentares preferidas, em ordem decrescente, são cebola, cravo, canela, orégano, alho, nóz-moscada, pimentão, cebolinha, endro e salsinha.

This study aimed to assess the ability of silicon (Si) to potentiate defense enzyme activities in rice leaf sheaths and thus reduce sheath blight, caused by Rhizoctonia solani, development. Rice plants of BR-Irga 409 and Labelle cultivars were grown in a hydroponic solution containing 0 (-Si) or 2 mM (+Si) Si and inoculated with R. solani. Silicon concentration in the leaf sheaths was significantly higher in the +Si plants than the -Si plants by 727% for BR-Irga 409 and 714% for Labelle. The area under relative lesion expansion progress curve was significantly lower for +Si plants than -Si plants, by 34.2% for BR-Irga 409 and 30.59% for Labelle. Increases in the activities of phenylalanine ammonia-lyases, peroxidases, polyphenoloxidases and chitinases in the leaf sheaths of plants supplied with Si, especially of those from BR-Irga 409, led to reduced progress of sheath blight lesions. Key words: Oryza sativa, fungal disease, host defense response, mineral nutrition, sheath blight.Rice (Oryza sativa L.) is one of the most important carbohydrate sources for the world population, and the occurrence of sheath blight, caused by the necrotrophic fungus Rhizoctonia solani Kühn (teleomorph Thanatephorus cucumeris (A. B. Frank) Donk), has contributed to dramatically decrease yield (Ou, 1985). Severely infected plants produce poorly filled or empty grains, especially those on the lower portion of the panicle (Rush & Lee, 1992). The occurrence of severe sheath blight epidemics and the consequent reduction in yield have been favored by flood irrigation, rotation with soybeans and the use of high-yielding cultivars that are susceptible to the disease (Bedendo & Prabhu, 2005).Sheath blight needs to be managed to prevent yield losses caused by this disease worldwide. Soil amendment with various sources of soluble silicon (Si) has been proposed as an environmentally friendly choice for sheath blight management worldwide (Datnoff et al., 2007). Although Si is not considered an essential nutrient for plants, it is noted for its potential to decrease the intensity of important diseases in several crops, especially grasses (rice, sorghum and wheat) and some dicots (cucumber and soybean) (Datnoff et al., 2007). The increased blast resistance of rice plants when supplied with Si has been attributed to a higher density of long and short silicate cells in the leaf epidermis and/or the existence of a thick silica layer below the cuticle forming a physical barrier that prevents or slows Pyricularia grisea penetration (Kim et al., 2002). Increased concentrations of phenolics, lignins and phytoalexins, enhanced activity of defense-related enzymes (chitinases, β-1,3-glucanases and phenylalanine ammonialyases) and the rapid and strong induction of genes related to host defense against pathogens are the biochemical mechanisms that are potentiated by Si in rice (Rodrigues et al., 2003(Rodrigues et al., , 2004(Rodrigues et al., , 2005Liang et al., 2006;Brunings et al., 2009). This study aimed to determine the effects of Si on the activi...

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Parte da Tese de Doutorado da primeira autora. Universidade Federal de Viçosa. Viçosa MG. 2008. RESUMOA ferrugem, causada por Hemileia vastatrix, é a principal doença do cafeeiro. Este trabalho avaliou o efeito do silício (Si) em alguns componentes de resistência do cafeeiro à ferrugem e o possível aumento na atividade de quitinases (QUI), β-1,3-glucanases (GLU) e peroxidases (POX). Mudas de cafeeiro (cv. Catuaí vermelho 44) foram crescidas em solução nutritiva de Clarck modificada, aerada, contendo 0 (-Si) ou 2 mmol L -1 Si (+Si) por 45 dias e inoculadas com H. vastatrix. Não houve diferença significativa entre os tratamentos -Si e +Si para o teor foliar de Si, mas o teor desse elemento nas raízes foi significativamente maior para o tratamento +Si. Os tratamentos -Si e +Si não foram estatisticamente diferentes para o período de incubação, período latente, número de pústulas por folha, área pustular, expansão de pústulas e área abaixo da curva do progresso da ferrugem. A atividade de QUI, GLU e POX aumentou após a inoculação com H. vastatrix, embora com aumentos e decréscimos durante as épocas de coletas. O Si não teve efeito pronunciado em maximizar a atividade dessas enzimas, salvo incrementos em épocas de coletas específicas. Os resultados deste estudo indicaram que o cafeeiro foi ineficiente em translocar o Si das raízes para a parte aérea, restringindo-o exclusivamente ao sistema radicular o que não garantiu o aumento da resistência do cafeeiro à ferrugem Palavras-chave: Hemileia vastatrix, componentes de resistência, enzimas de defesa. ABSTRACT Inefficiency of silicon in leaf rust control on coffee grown in nutrient solutionCoffee leaf rust, caused by Hemileia vastatrix, is the most important disease on coffee. This study aimed to evaluate the effect of silicon (Si) on some components of coffee resistance to rust and to determine if it could increase the activity of chitinases (CHI), β-1,3-glucanases (GLU), and peroxidases (POX). Coffee plants (cultivar "Catuaí vermelho 44") were grown on aerated Clarck's nutrient solution containing 0 (-Si) or 2 mmol L -1 Si (+Si) for 45 days and inoculated with H. vastatrix. There was no significant difference between the -Si and +Si treatments for Si content in leaf tissue, but Si content in root tissue was significantly higher for the +Si treatment. The -Si and +Si treatments were not significantly different for incubation period, latent period, number of pustules per leaf, pustule size, pustule expansion, and area under rust progress curve. The activity of CHI, GLU, and POX increased after inoculation with H. vastatrix, even with increase or decrease in activities during the sampling times. There was not a pronounced effect of Si in increasing the activity of these enzymes, except for rare increases in specific sampling times. Results from this study indicated that coffee plants were inefficient in uptaking Si from the nutrient solution and translocating it to the shoot. Silicon was exclusively restricted to the root system, which did not guarantee an increase in coff...