14 research outputs found

    Efeitos de materiais org√Ęnicos e da umidade do solo na patogenicidade de Rhizoctonia solani K√ľhn GA-4 HGI ao feijoeiro

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    The pathogenicity of Rhizoctonia solani AG-4 HGI on bean (Phaseolus vulgaris L.) plants was evaluated, in artificially infested soil under greenhouse conditions, when submitted to the following treatments: amendments with different C:N ratios (castor-oil cake and sugar-cane bagasse); different organic matter decomposition levels; different moisture contents of the amended soil. Until the moment of sowing the soil moisture was maintained at 20% of the moisture-holding capacity or above 80%. The sowings were made at 0, 7, 14, 21, 28 and 35 days after the inoculation and amendments incorporation. Evaluations were carried out 14 days after each sowing date. The amendment with low C:N ratio increased the incidence of R. solani on bean plants, in any decomposition level, whereas the amendment with high C:N ratio did not interfere on the incidence of the pathogen. The incidence of R. solani on bean plants, in a soil amended with both castor-oil cake or sugar-cane bagasse, was independent of the soil moisture condition.Foram avaliados, em casa de vegeta√ß√£o, os efeitos das seguintes vari√°veis sobre a patogenicidade de Rhizoctonia solani GA-4 HGI a plantas de feij√£o (Phaseolus vulgaris L.), em solo artificialmente infestado: presen√ßa de materiais org√Ęnicos com diferentes rela√ß√Ķes C:N (torta de mamona e baga√ßo de cana); n√≠veis de decomposi√ß√£o da mat√©ria org√Ęnica, e condi√ß√Ķes de umidade do solo incorporado. A umidade do solo at√© o momento da semeadura foi mantida sob duas condi√ß√Ķes: 20% ou acima de 80% da capacidade de campo. Foram realizadas semeaduras aos 0, 7, 14, 21, 28 e 35 dias ap√≥s inocula√ß√£o e incorpora√ß√£o. As avalia√ß√Ķes foram realizadas 14 dias ap√≥s cada semeadura. O material com baixa rela√ß√£o C:N propiciou o aumento da incid√™ncia de R. solani no feijoeiro, enquanto o material com alta rela√ß√£o C:N n√£o interferiu na incid√™ncia do pat√≥geno. A incid√™ncia de R. solani no feijoeiro, em solo incorporado, foi independente da condi√ß√£o de umidade

    Efeitos de materiais org√Ęnicos e da umidade do solo na patogenicidade de Rhizoctonia solani K√ľhn GA-4 HGI ao feijoeiro

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    The pathogenicity of Rhizoctonia solani AG-4 HGI on bean (Phaseolus vulgaris L.) plants was evaluated, in artificially infested soil under greenhouse conditions, when submitted to the following treatments: amendments with different C:N ratios (castor-oil cake and sugar-cane bagasse); different organic matter decomposition levels; different moisture contents of the amended soil. Until the moment of sowing the soil moisture was maintained at 20% of the moisture-holding capacity or above 80%. The sowings were made at 0, 7, 14, 21, 28 and 35 days after the inoculation and amendments incorporation. Evaluations were carried out 14 days after each sowing date. The amendment with low C:N ratio increased the incidence of R. solani on bean plants, in any decomposition level, whereas the amendment with high C:N ratio did not interfere on the incidence of the pathogen. The incidence of R. solani on bean plants, in a soil amended with both castor-oil cake or sugar-cane bagasse, was independent of the soil moisture condition.Foram avaliados, em casa de vegeta√ß√£o, os efeitos das seguintes vari√°veis sobre a patogenicidade de Rhizoctonia solani GA-4 HGI a plantas de feij√£o (Phaseolus vulgaris L.), em solo artificialmente infestado: presen√ßa de materiais org√Ęnicos com diferentes rela√ß√Ķes C:N (torta de mamona e baga√ßo de cana); n√≠veis de decomposi√ß√£o da mat√©ria org√Ęnica, e condi√ß√Ķes de umidade do solo incorporado. A umidade do solo at√© o momento da semeadura foi mantida sob duas condi√ß√Ķes: 20% ou acima de 80% da capacidade de campo. Foram realizadas semeaduras aos 0, 7, 14, 21, 28 e 35 dias ap√≥s inocula√ß√£o e incorpora√ß√£o. As avalia√ß√Ķes foram realizadas 14 dias ap√≥s cada semeadura. O material com baixa rela√ß√£o C:N propiciou o aumento da incid√™ncia de R. solani no feijoeiro, enquanto o material com alta rela√ß√£o C:N n√£o interferiu na incid√™ncia do pat√≥geno. A incid√™ncia de R. solani no feijoeiro, em solo incorporado, foi independente da condi√ß√£o de umidade

    Caracteriza√ß√£o citomorfol√≥gica, cultural, molecular e patog√™nica de Rhizoctonia solani K√ľhn associado a soja no Brasil

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    Rhizoctonia solani representa um pat√≥geno de import√Ęncia econ√īmica mundial nas √°reas de cultivo da soja. Pode estar associado a v√°rios sintomas como tombamento, podrid√£o de ra√≠zes e hipoc√≥tilos e mela ou requeima da soja. No Brasil, os n√≠veis de danos pela mela em soja variam de 31 a 60%, em lavouras dos Estados do Norte e Nordeste. R. solani est√° dividido em 14 grupos de anastomose (AG), que diferem quanto aos aspectos culturais, virul√™ncia e fisiologia. Desta forma, objetivou-se caracterizar AG de R. solani associados √† soja no Brasil. Dentre 73 isolados analisados quanto a condi√ß√£o nuclear, 6 foram binucleados e 67 multinucleados. Os isolados multinucleados (R. solani) foram caracterizados atrav√©s de anastomose de hifas, temperaturas limites para crescimento micelial, requerimento de tiamina, temperatura letal, produ√ß√£o de escler√≥dios e compara√ß√Ķes por RAPD. Atrav√©s de anastomose de hifas, 4 isolados causadores de tombamento e podrid√£o de hipoc√≥tilos foram caracterizados como AG-4. An√°lises de RAPD permitiram verificar que tr√™s, desses quatro isolados, pertenciam ao AG-4 HGII, e o outro ao AG-4 HGI. Atrav√©s da fus√£o de hifas com AG-2-2 IIIB, crescimento a 35oC e auxotrofismo para tiamina, foi caracterizado um isolado, causador de tombamento e podrid√£o de ra√≠zes e hipoc√≥tilos. Sessenta e dois isolados, causadores de mela, realizaram anastomose de hifas com o AG-1 IA apresentando em m√©dia 19,3 mm/dia de crescimento radial , formando escler√≥dios tipo ‚Äėsasakii‚Äô, caracter√≠sticos desse subgrupo. O enquadramento desses isolados no subgrupo IA foi confirmado pela an√°lise de RAPD entre os isolados de R. solani de soja e padr√Ķes dos subgrupos do AG-1. Estruturas sexuais de Thanatephorus cucumeris (anamorfo R. solani) foram produzidas por um isolado do AG-1 IA, em condi√ß√Ķes de estufa biol√≥gica √† temperatura de 28¬Ī1oC... .Rhizoctonia solani represents a pathogen economically important in all soybean-growing areas in the world. It causes pre- and post-emergence damping-off, root and hypocotyl rot and foliar blight of soybean. Foliar blight has resulted in yield losses of 31-60% in North and Northeast of Brazil. R. solani is divided into 14 anastomosis groups (AG), that differ in cultural appearance, virulence, physiology and genetic. The aim of this study was to characterize R. solani isolates associated with soybean in Brazil. Among seventy-three Rhizoctonia isolates examined according to nuclear condition, six were binucleate and sixtyseven were multinucleate. The multinucleate isolates (R. solani) were characterized according to anastomosis group, limit temperature to radial growth, thiamine requirement, lethal temperature, sclerotia production and molecular marker RAPD. Four isolates, cause of damping-off and hypocotyl rot, belonged to AG-4. RAPD analysis showed that among four isolates of AG-4, three grouped with HGII and one belonged to HGI subgroup. Other isolate, cause of damping-off and root and hypocotyl rot, growth at 35oC in the dark and thiamine auxotrophic, belonged to AG-2-2 IIIB. Sixty-two isolates, cause of foliar blight, belonged to AG-1 IA. The mean radial growth rate was 19,3 mm/day and producing sasakii-type sclerotia, characteristic to the IA subgroup. RAPD analysis among R. solani AG-1 IA isolates of the soybean and anastomosis group testers, corroborate the characterization in IA subgroup. Perfect-stage Thanatephorus cucumeris (anamorph Rhizoctonia solani) was produced by one AG-1 IA isolate, in incubator at 28¬Ī1oC. The AG-4 and AG-2-2 IIIB isolates were pathogenic in soybean seedlings cv. ‚ÄėFT-Cristalina‚Äô, under greenhouse condition, causing damping-off and root and hypocotyl rot. The AG-2-2 IIIB isolate caused large lesions and cortex... (Complete abstract, click electronic address below).Funda√ß√£o de Amparo √† Pesquisa do Estado de S√£o Paulo (FAPESP

    EFEITO DE FUNGICIDAS NO CONTROLE DO MILDIO (Peronospora sparsa Berk.) EM ROSEIRA (Rosa sp.), EM PATOSSISTEMA NATURAL

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    Avaliou-se a efic√°cia de fungicidas para o controle do m√≠ldio em roseira. O experimento foi conduzido em Paranapanema - SP, com roseiras de 2 anos de idade, em condi√ß√Ķes de campo. Foi realizada uma pulveriza√ß√£o, utilizando-se 800 L.ha-1 de volume de calda, com os princ√≠pios ativos e doses (kg i.a.ha-1): iprovalicarb + propineb (1,1 + 1,225), iprovalicarb + propineb (1,375 + 1,531), propineb (1,750), propineb (2,1) e metalaxyl + mancozeb (0,2 + 1,6). Quinze dias antes da aplica√ß√£o dos tratamentos foi realizada a poda dos ramos, com a finalidade de estimular brota√ß√Ķes novas e, consequentemente, bot√Ķes florais. No momento da aplica√ß√£o dos tratamentos, fora. 'TI selecionadas e marcadas quinze brota√ß√Ķes novas, isentas de sintomas do ataque de P. sparsa, nas quais foram realizadas as avalia√ß√Ķes. As avalia√ß√Ķes foram efetuadas aos 3, 5, 12 e 19 dias ap√≥s aplica√ß√£o dos tratamentos, contando-se todas as folhas, ramos e bot√Ķes, computando-se aqueles com os sintomas da doen√ßa, para a determina√ß√£o da porcentagem de folhas atacadas, por ramo marcado. Todos os fungicidas utilizados, isolados ou em mistura, proporcionaram o controle do m√≠ldio em condi√ß√Ķes de campo, at√© 19 dias ap√≥s aplica√ß√£o dos mesmos

    Identification of 14-3-3-like protein in sugarcane (Saccharum officinarum)

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    In a search of the sugarcane expressed sequence tag (SUCEST) database we located three full-length cDNAs (SCCCLR1022D05.g, SCCCRZ1001D02.g and SCBFLR1026E02.g) encoding the 14-3-3 proteins from sugarcane (Saccharum officinarum). The encoded proteins were identified based on the clustering of the expressed sequence tags and were shown to encode proteins similar to 14-3-3 proteins of other monocotyledonous plants. Cluster SCCCLR1022D05.g was 99% similar to the maize 14-3-3-like protein (gi|1345587) while cluster SCCCRZ1001D02.g shared 96% and SCBFLR1026E02.g 94% similarity with the 14-3-3 protein of rice (gi|7435022). Although 14-3-3 proteins have been reported to be specific to particular species, tissue or organ from which they were isolated, all three sugarcane clusters were found to be expressed in several tissues.Seq√ľ√™ncias completas de tr√™s cDNAs que codificam prote√≠nas 14-3-3 de cana-de-a√ß√ļcar (Saccharum officinarum) foram encontradas no projeto genoma EST de cana-de-a√ß√ļcar. As prote√≠nas codificadas por essas seq√ľ√™ncias foram identificadas baseando-se no agrupamento de ESTs de cana-de-a√ß√ļcar e, tr√™s "clusters" (SCCCLR1022 D05.g, SCCCRZ1001D02.g e SCBFLR1026E02.g) foram similares a prote√≠nas 14-3-3 de outras monocotiled√īneas. O cluster SCCCLR1022D05.g apresentou similaridade de 99% com a prote√≠na 14-3-3 de milho (gi|1345587) e, os clusters SCCCRZ1001D02.g e SCBFLR1026E02.g foram similares a prote√≠na 14-3-3 de arroz (gi|7435022), 96% e 94%, respectivamente. Embora prote√≠nas 14-3-3 t√™m sido relatadas como sendo espec√≠ficas a organismos, tecidos e √≥rg√£os, todos os "clusters" de cana-de-a√ß√ļcar correspondentes a 14-3-3 foram provenientes de cDNAs advindos de diferentes tecidos

    Characterization of Rhizoctonia solani associated with soybean in Brazil

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    Rhizoctonia solani causes pre- and post-emergence damping-off, root and hypocotyl rot and foliar blight in soybean. Foliar blight has resulted in yield losses of 31-60% in north and northeast Brazil. The aim of this study was to characterize isolates of R. solani associated with soybean in Brazil. Among 73 Rhizoctonia isolates examined, six were binucleate and 67 were multinucleate. The multinucleate isolates were characterized according to hyphal anastomosis reaction, mycelial growth rate, thiamine requirement, sclerotia production, and RAPD molecular markers. Four isolates that caused hypocotyl rot belonged to AG-4 and using RAPD analysis they grouped together with the HGI subgroup. Another isolate that caused root and hypocotyl rots was thiamine auxotrophic, grew at 35 ¬įC, and belonged to AG-2-2 IIIB. All 62 isolates that caused foliar blight belonged to AG-1 IA. RAPD analysis of R. solani AG-1 IA soybean isolates showed high genetic similarity to a tester strain of AG-1 IA, confirming their classification. The teleomorph of R. solani, Thanatephorus cucumeris was produced in vitro by one AG-1 IA isolate from soybean. The AG-4 and AG-2-2 IIIB isolates caused damping-off and root and hypocotyl rots of soybean seedlings cv. 'FT-Cristalina', under greenhouse conditions. The AG-2-2 IIIB isolate caused large lesions on the cortex tissue, that was distinct from the symptoms caused by AG-4 isolates. The AG-1 IA isolates caused foliar blight in adult soybean plants cv. 'Xingu' under the greenhouse and also in a detached-leaf assay
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