Phaseolin Induction on Common-Bean Cultivars and Biological Control of Colletotrichum lindemuthianum 89 Race by Baccharis trimera (Less) Dc

Abstract The objective of this work was to evaluate the fungitoxic effect of the aqueous extracts of Baccharis trimera on the mycelial growth of Colletotrichum lindemuthianum 89 race, as well as its effect on the accumulation of phaseolin in hypocotyls of different cultivars and common bean varieties. It was obtained 20% aqueous extract from plants collected in municipalities of the Western Region of Paraná. Blocks containing C. lindemuthianum mycelium were transferred to Petri dishes containing medium with the different extracts and incubated at 25 °C. The colonies diameter was measured until the 12th day. Effects of aqueous extracts on phaseolin production was evaluated in hypocotyls of Carioca, Cnpf 8104, Soberana, Tibatã, Uirapurú cultivars, as well as Rosinha and Vermelho varieties. Each one cultivar and variety hypocotyl was transferred separately to test tubes containing 500 μL of 20% aqueous extracts. Sterile water, Bion®, and UV was used as controls. The phaseolin production was measured in spectrophotometer [280 nm]. Results of the evaluation of the antifungal activity of aqueous extracts of Baccharis sp. specimens collected indicate that approximately 50% of the samples presented capacity to reduce between 74 and 92% of C. lindemuthianum growth. Cultivar Tibatã and Vermelho variety showed greater sensitivity over the applied treatments. Results of fungal filtrates and vegetal aqueous extracts presented a low capacity to induce the production of phaseolin in hypocotyls.

Potencial de preparados de cavalinha (Equisetum sp. ) na síntese de metabólitos de defesa em cotilédones de soja (Glycine max L. ) e o efeito sobre o crescimento de Rhizoctonia solani Kuhn, in vitro / Potential of horsetail (Equisetum sp. ) derivatives on the synthesis of defense metabolites using soybean ( Glycine max L. ) cotyledons and their effect on the in vitro growth of Rhizoctonia solani Kuhn

Foram desenvolvidos dois experimentos com objetivo de avaliar o potencial de preparados de cavalinha (Equisetum sp.) na síntese de metabólitos de defesa em cotilédones de soja (Glycinemax L.) e o efeito sobre o crescimento de Rhizoctonia solani, in vitro. O delineamento experimental utilizado para os experimentos foi inteiramente casualizado em esquema fatorial 3x5 (formas de extração x concentrações), com quatro repetições. As formas de extração foram extrato alcoólico, infusão e maceração, nas concentrações de zero; 1; 10, 20 e 40%. No primeiro experimento foi avaliada a indução de compostos de defesa vegetal em cotilédones de soja em resposta aos derivados a base de cavalinha, sendo quantificada a atividade da enzima fenilalanina amônia-liase (FAL), via espectofotometria, a fitoalexina gliceolina, e o teor de fenóis totais. No segundo experimento, in vitro, a unidade experimental foi uma placa de Petri, sendo os preparados de cavalinha incorporados ao meio BDA (Batata-dextrose e Agar) e avaliado o crescimento micelial de R. Solani. Os preparados de extrato alcoólico, infusão e maceração de cavalinha apresentaram capacidade de indução das fitoalexinas gliceolinas em cotilédones de soja, bem como, ativaram o metabolismo de compostos fenólicos. Entre os preparados, o extrato alcoólico e a maceração, se sobressaem sobre a infusão. Os preparados de extrato alcoólico, infusão e maceração de cavalinha em todas as suas concentrações inibem o crescimento do fungo R. solani, in vitro. .

Two experiments were carried out in the Federal Technological University of Paraná - Dois Vizinhos Campus - with the aim to evaluate the potential of horsetail (Equisetum sp.) derivatives for the synthesis of defense metabolites in soybean (Glycine max L.) cotyledons and their effect on the in vitro growth of Rhizoctonia solani. The experimental design was completely randomized in a 3 x 5 factorial design (extraction form x concentration), with four replications. The extraction forms were alcoholic extract, infusion and maceration and the concentrations tested were zero, 1, 10, 20 and 40%. In the first experiment, we evaluated the induction of plant defense in soybean cotyledons as a response to horsetail derivatives through spectrophotometry according to phytoalexin glyceollin, phenylalanine ammonia lyase enzyme activity (PAL) and total phenols. In the second experiment, in vitro, the experimental unit was a Petri dish, and the horsetail derivatives were incorporated into medium culture (potato dextrose agar), and we evaluated the mycelial growth of R. solani. The alcoholic extract, infusion and maceration of horsetail derivatives presented phytoalexin glyceolin induction in soybean cotyledons, in addition to activating the metabolism of phenolic compounds. Among the derivatives, the alcoholic extract and the maceration form of extraction were superior in relation to the infusion. The alcoholic extract, infusion and maceration of horsetail derivatives inhibited the in vitro growth of R. solani in all concentrations.

The Resveratrol-induced Relaxation of Cholecystokinin Octapeptide- or KCl-induced Tension in Male Guinea Pig Gallbladder Strips Is Mediated Through L-type Ca2+ Channels

BACKGROUND/AIMS: Resveratrol (3,5,4'-trihydroxystilbene) is a polyphenolic compound (stilbene) and a phytoalexin. The purpose of this study was to determine the mechanism which mediated the resveratrol-induced relaxation of cholecystokinin octapeptide- or KCl-induced tension in male guinea pig gallbladder strips. METHODS: Gallbladder strips were prepared and suspended in in vitro chambers filled with Krebs-Henseleit solution. The strips were attached to force displacement transducers, and the changes in tension were recorded on a polygraph. All reagents were added directly into the chambers. RESULTS: To determine if intracellular Ca2+ release mediated the resveratrol-induced relaxation of cholecystokinin octapeptide-induced tension, 2-aminoethoxydiphenylborane (2-APB) was used. 2-APB significantly (P < 0.01) decreased the amount of RSVL-induced relaxation. To determine if protein kinase A (PKA) mediated the resveratrol-induced relaxation, PKA inhibitor 14-22 amide myristolated (PKA-IM) was used. PKA-IM had no effect on resveratrol-induced relaxation. Neither KT5823, N(G)-methyl-L-arginine acetate salt, a nitric oxide synthase inhibitor, nor fulvestrant had a significant effect on the amount of resveratrol-induced relaxation. Genistein, a protein tyrosine kinase inhibitor, significantly (P < 0.01) increased the RSVL-induced relaxation. To determine if protein kinase C mediated the RSVL-induced relaxation, the protein kinase C inhibitors bisindolymaleimide IV and chelerythrine Cl- were used together, and a significant (P < 0.05) increase in resveratrol-induced relaxation was observed. The pretreatment of the strips with resveratrol significantly (P < 0.001) decreased the amount of KCl- and cholecystokinin octapep-tide-induced tension. CONCLUSIONS: Resveratrol-induced relaxation is mediated by its effects on L-type Ca2+ channels and intracellular Ca2+ release.

Efeito de extratos de cogumelos na indução de fitoalexinas e no controle de oídio da soja em casa de vegetação / Mushrooms extracts effect on the induction of phytoalexins and on the control of soybean powdery mildew in greenhouse

O oídio (Erysiphe diffusa) tornou-se uma das principais doenças que afeta a cultura da soja (Glycine max), podendo causar redução significativa no rendimento da cultura. Esse trabalho teve por objetivo avaliar o efeito dos extratos aquosos de Agaricus blazei, Lentinula edodes e Pycnoporus sanguineus no controle do oídio em casa-devegetação e na indução de fitoalexinas em cotilédones de soja. O delineamento experimental utilizado foi inteiramente casualizado com cinco repetições. Como controle utilizou-se fungicida (enxofre ­ 3g/L) e testemunha - sem aplicação. Os tratamentos utilizados foram: extratos aquosos de Agaricus blazei, Lentinula edodes e Pycnoporus sanguineus na concentração de 20 %v/v sendo estes aplicados aos 61 e 68 dias após a semeadura. Avaliou-se a incidência e severidade aos 59, 65, 69, 73 e 77 dias após a semeadura em todos os folíolos de cada planta. Com os dados da severidade, calculouse a área abaixo da curva de progresso da doença (AACPD). Para a incidência, detectou-se diferença significativa entre o fungicida e os demais tratamentos. Para severidade e AACPD, observou-se que os extratos diferiram da testemunha, sendo que L. edodes mostrou ser mais eficiente que os demais tratamentos. Para o bioensaio de fitoalexinas foi aplicado sobre cada cotilédone de soja uma alíquota de 75 µL de cada extrato aquoso nas concentrações de 1%, 2%, 4% e 10%. Após 20 horas, os mesmos foram transferidos para erlenmeyers contendo 15 mL de água destilada esterilizada e deixados em agitação por 1 h para extração da fitoalexina formada. A absorbância foi determinada a 285 nm em espectrofotômetro. Observou-se um maior acúmulo de fitoalexina nas maiores concentrações dos extratos aquosos.

The powdery mildew (Erysiphe diffusa) became one of the main diseases that effects soybean (Glycine max) crops. The aim was to evaluate the effect of Agaricus blazei, Lentinula edodes and Pycnoporus sanguineus aquous extracts on the control of powdery mildew in greenhouse and on the induction of phytoalexins in soybean cotyledons. The control treatments consisted of fungicide (Sulphur ­ 3 g/L) and control without application. The treatments were applied at 61 and 68 days after sowing (DAS). The incidence and severity was evaluated at 59, 65, 69, 73 and 77 DAS in all the folioles of each plant. With the severity values, the area under the disease progress curve (AUDPC) was estimated. To the incidence, a significative difference was detected between the fungicide and the other treatments. For severity and the AUDPC, the extracts and the fungicide differed from the control and L. edodes was the most efficient treatment. For the phytoalexins production was applied 75 mL to each soybean cotyledon of each aqueous extract at 1%, 2%, 4% and 10% concentrations. After 20 hours, they were transferred to erlenmayer flask containing 15 mL of sterile distilled water and remained stirring for 1 h for extraction of phytoalexin. The absorbance was measured at 285 nm in a spectrophotometer. The highest accumulation of the phytoalexins was observed on highests concentrations of the aqueous extracts.

Extratos de alho e alecrim na indução de faseolina em feijoeiro e fungitoxicidade sobre Colletotrichum lindemuthianum / Garlic and rosemary extracts in the induction of phaseollin in beans and fungitoxicity on Colletotrichum lindemuthianum

Extratos vegetais podem auxiliar no controle de doenças de plantas, por sua atividade antimicrobiana ou pela ativação de mecanismos de defesa. Neste trabalho, objetivou-se avaliar o efeito dos extratos aquosos de alho e alecrim autoclavados e não autoclavados sobre o crescimento micelial de Colletotrichum lindemuthianum, a produção de faseolina em feijoeiro e a severidade de antracnose em campo. O fungo foi incubado em meio de cultura contendo os extratos, e o crescimento foi mensurado por 18 dias. Para avaliação de faseolina, os extratos foram aplicados sobre hipocótilos de feijão, a extração foi feita em etanol e a leitura foi realizada em espectrofotômetro. A severidade da antracnose foi avaliada em plantas de feijão pulverizadas com os extratos e inoculadas com o fungo. Para o extrato de alho, a maior redução (57,6 por cento) no crescimento micelial foi com a dose de 3,0 por cento do extrato não autoclavado. Já para o extrato de alecrim, a maior redução (18,6 por cento) foi com o extrato autoclavado. A autoclavagem não teve efeito sobre a indução de faseolina. À campo, os extratos não reduziram significativamente a severidade de antracnose. O extrato de alho não autoclavado mostrou-se mais eficiente na redução do crescimento de C. lindemuthianum, enquanto que o de alecrim, autoclavado ou não, foi mais efetivo na indução de faseolina.

Plant extracts may assist in controlling plants diseases due to its antimicrobial activity and activation of defense mechanisms. This study aimed to evaluate the effect of aqueous extracts of garlic and rosemary, autoclaved or non autoclaved, on the mycelial growth of Colletotrichum lindemuthianum, production of phaseollin by beans and severity of anthracnose in the field. The fungus was incubated in medium containing the extracts and its growth measured for 18 days. For phaseollin evaluation the extracts were applied on bean hypocotyls, the phytoalexin extracted in ethanol and read in spectrophotometer. The severity of anthracnose was evaluated in bean plants sprayed with the extracts and inoculated with the fungus. For the garlic extract, the greater reduction (57,6 percent) in micelial growth was at 3 percent in the non autoclaved extract, as for the rosemary extract, the greater reduction (18,6 percent) was in the autoclaved extract. Autoclaving had no effect on the induction of phaseollin. At field conditions, the extracts did not reduce significantly the severity of anthracnose. The non autoclaved garlic extract showed to be more efficient in reducing the mycelial growth of C. lindemuthianum, while rosemary, autoclaved or not, proved to be more effective in the induction of phaseollin.

Induction and accumulation of phytoalexins in cowpea roots infected with a mycorrhizal fungus Glomus fasciculatum and their resistance to Fusarium wilt disease.

The interaction of a vesicular-arbuscular mycorrhizal fungus Glomus fasciculatum with a wilt-causing soil borne pathogen, Fusarium oxysporum, was studied in cowpea (Vigna unguiculata). It was found that pre-establishment by vesicular-arbuscular mycorrhizal fungus reduced the colonization of the pathogen and the severity of the disease, as determined by reduction in vascular discolouration index. In mycorrhizal plants, the production of phytoalexin compounds was always higher than in the nonmycorrhizal plants. There appeared to be a direct correlation between the concentration of the phytoalexins and the degree of mycorrhizal association. Three different compounds with Rf values of 0·23 (I), 0·17 (II) and 0·11 (III) were obtained from mycorrhizal plants. Similar compounds were also found to be induced by an abiotic elicitor CuSO4. The first compound was identified as an isoflavonoid, daidzein and the other two remain to be identified. These compounds were checked for their antifungal activity in vitro. The germination of conidial spores of Fusarium oxysporum was strongly inhibited by the compound III than the other two. It is argued that the production of phytoalexin compounds in mycorrhizal plant could be one of the mechanisms imparting tolerance of the plants to wilt disease.