Odair José Kuhn

Induction of resistance in beans against Pseudocercospora griseola by culture filtrates of Pycnoporus sanguineus

With the aim of developing an alternative method for the control of angular leaf spot of common bean, caused by Pseudocercospora griseola, aqueous extracts of Pycnoporus sanguineus culture filtrates were evaluated in vitro for antimicrobial activity against P. griseola, and possible induction of resistance in bean against P. griseola. The role of the defense enzymes peroxidase, polyphenol oxidase, and β-1,3-glucanase, and the content of proteins and chlorophyll, were also investigated. For the in vitro and greenhouse experiments the culture filtrate of P. sanguineus at the concentrations of 1 to 20% was used, and water, acibenzolar-S-methyl (ASM: 75 mg i.a. L-1) and fungicide (azoxystrobin: 40 mg i.a. L-1) served as control treatments. In the in vitro study, culture filtrate did not inhibit mycelial growth, sporulation and conidia germination of P. griseola. The total area under the angular leaf spot progress curve was reduced by 82 and 49% respectively, for greenhouse and field experiments in relation to the water control. The activities of peroxidase and polyphenol oxidase, and the content of proteins and chlorophylls, increased in plants treated with the extract. The results from this study indicate the potential of P. sanguineus culture filtrate as an alternative control for angular leaf spot on beans.

Resistance induction in bean plants against angular leaf spot by extracts from Pycnoporus sanguineus mycelium

Angular leaf spot, caused by the fungus Pseudocercospora griseola, is a major disease of common bean (Phaseolus vulgaris L.) in Brazil. The objective of this research was to develop an alternative method for controlling this disease based on an aqueous extract of Pycnoporus sanguineus mycelium. It was evaluated the antimicrobial activity of the aqueous extract against P. griseola as well as its activity of resistance induction against angular leaf spot. The role of the plant defense enzymes peroxidase, polyphenol oxidase and β-1,3-glucanase, and the proteins and chlorophyll content was investigated. The experiments in vitro and in greenhouse used extracts from mycelium of P. sanguineus and water, Acibenzolar-S-methyl (ASM: 75 mg/L) and the fungicide azoxystrobin (40 mg/L) were the control treatments. In vitro, the extract of mycelium inhibited the mycelial growth as well as the sporulation and conidia germination of P. griseola. However severity was reduced in 93% and 50% in greenhouse and field respectively. The activities of peroxidase, polyphenol oxidase and the content of proteins and chlorophylls had an increment in plants treated with extract. These results indicate the potential of P. sanguineus for alternative control of the angular leaf spot in bean.

Atividade antioxidante, composição química e conservação do maracujá-amarelo embalado com filme PVC

The aim of this study was to evaluate the chemical characteristics and conservation of yellow passion fruit packed with PVC film during refrigerated at 5 oC. Antioxidant activity (DPPH and TEAC), total phenolic compounds, β-carotene and ascorbic acid of the fruit juice were the chemical parameters. Estimations of weight loss, wrinkling, color and symptoms of pathogens were used in the conservation study. The evaluations were performed in 10-day intervals for 40 days. According to the results, the total phenolic content increased during storage, varying between 20.10 and 21.29 mg EAG 100 mL-1. The contents of ascorbic acid increased until the 20th day of storage (33.58 mg 100 mL-1), but followed with decreases until the 40th day (21.67 mg 100 mL-1). Regardless of the use of PVC, β-carotene did not change during storage. The TEAC and DPPH antioxidant activity in juice decreased during storage. The DPPH and TEAC antioxidant activity did not correlate positively with total phenolics, suggesting that phenolic compounds do not contribute to the antioxidant activity of passion fruit juice. The use of PVC packaging did not influence positively on the antioxidant activity and the contents of total phenolics and ascorbic acid of yellow passion fruit juice during storage. The PVC did not inhibit the pathogens-degradation symptoms for up to 30 days of storage, at 5 oC, but reduced the weight loss and wrinkling of the fruit, providing optimal conditions of merchantability for up to 20 days.

Controle biológico de antracnose em pós-colheita de banana “Maçã” com Saccharomyces spp.

Este trabalho objetivou analisar o controle biologico do Colletotrichum musae em bananas por meio de Saccharomyces cerevisiae e Saccharomyces boulardii. Celulas de S. cerevisiae foram obtidas a partir do fermento de panificacao Fleischmann®. Celulas de S. boulardii foram obtidas a partir do medicamento Floratil®. Utilizou-se um cacho de banana colhido de area orgânica, os frutos passaram por um processo de assepsia, em seguida foram tratados com celulas de S. cerevisiae, S. boulardii e ambas as leveduras na concentracao de 2 g L-1, apos 24 horas inoculou-se o C. musae em tres pontos por fruto. Para avaliar-se o efeito da concentracao de celulas no tratamento o processo foi repetido, tratando-se os frutos com concentracoes de 0; 0,5; 1; 2; 4 e 8 g L-1 de S. cerevisiae e S. boulardii, avaliou-se a area lesionada, a cada 48 horas, por 14 dias. Tambem avaliou-se o halo de inibicao e a producao de compostos volateis, ambos in vitro, para analisar se ha ocorrencia de antagonismo. Observou-se que o tratamento com as leveduras reduz o progresso da doenca, e que S. cerevisiae e S. boulardii apresentam maior eficiencia na concentracao de 5,5 e 6,3 g L-1, respectivamente, apresentando reducao de 48% e 35% do progresso da doenca, respectivamente. Observou-se a formacao de halo de inibicao e producao de compostos volateis, indicando que estas leveduras atuam por meio de antagonismo. Deste modo, estas leveduras sao potencias agentes de controle biologico do C. musae.

Induction of defense enzymes and control of anthracnose in cucumber by Corymbia citriodora aqueous extract

Secondary compounds of medicinal plants can activate defense mechanisms in plants against pathogens. The aqueous extract (AE) of Corymbia citriodora has shown that activity, but there is scarce information about the involved mechanisms of action. Therefore, this study aimed to evaluate the effect of AE on the induction of defense enzymes and protection of cucumber from Colletotrichum lagenarium. Thus, the AE, autoclaved or not, was evaluated for its capability of protecting and inducing peroxidases, polyphenoloxidases, chitinases and β-1.3-glucanases, and phenylalanine ammonia-lyase. Distilled water and acibenzolar-S-methyl (50 mg a.i. L) were used as controls. The effect of AE at the concentrations of 1, 5, 10, Franzener, G.; Schwan-Estrada, K.R.F.; Moura, G.S.; Kuhn, O.J.; Stangarlin, J.R. Induction of defense enzymes and control of anthracnose in cucumber by Corymbia citriodora aqueous extract. Summa Phytopathologica, v.44, n.1, p.10-16, 2018. 15 and 20% was also evaluated, as well as its local and systemic effect, and the effect of one or two applications. Pathogen inoculation or sample collection for determination of enzyme activity was performed at 72 hours after treatments. The AE reduced the severity of C. lagenarium and induced peroxidases and β-1.3-glucanases by 37.6, 67.2 and 122.7%, respectively. There was a reduction in the disease severity and an increase in peroxidases from the concentration of 5% AE. The latter showed only local effect and greater reduction in severity when two applications were performed. These results suggest the effect of AE in inducing resistance in cucumber and inducing peroxidases and β-1.3-glucanases.

Indução de resistência à Macrophomina phaseolina em soja tratada com extrato de alecrim

1 Universidade Estadual do Oeste do Paraná – UNIOESTE, Rua Pernambuco 1777, CP 91, CEP 85960-000, Marechal Cândido Rondon – Paraná – Brasil. jose.stangarlin@unioeste.br; ojkuhn@gmail.com. Universidade Federal do Paraná – UFPR, Rua Pioneiro 2153, CEP 85950-000, Palotina – Paraná – Brasil. roberto.portz@ufpr.br. 3 Bolsista CAPES Autor para correspondência: Eloisa Lorenzetti (eloisa-lorenzetti@hotmail.com) Data de chegada: 10/03/2017. Aceito para publicação em: 15/09/2017. 10.1590/0100-5405/176895

Fungitoxicity activity of Phosphorus and Calcarea carbonica against Sclerotinia sclerotiorum and control of white mold in common bean (Phaseolus vulgaris) with extremely diluted aqueous solutions

Common bean (Phaseolus vulgaris L.) is one of the main Brazilian agricultural crops. Numerous diseases have affected such a crop during its life cycle, such as white mold, caused by Sclerotinia sclerotiorum. This fungus is quite aggressive and requires an intensive use of pesticides. This study aimed at evaluating white mold control and antimicrobial activity against S. sclerotiorum using extremely diluted aqueous solutions of Phosphorus and Calcarea carbonica, at 6CH, 12CH, 24CH, 36CH and 48CH dynamizations (centesimal Hahnemannian). The tests were carried out in a completely randomized design, with 10 treatments and 5 replicates each, considering water as control. Variables including disease progression, the number of dead plants, the number of sclerotia, and mycelial growth were evaluated by in vivo and in vitro tests. The treatments Phosphorus 12CH, Phosphorus 48CH, Calcarea carbonica 12CH, and Calcarea carbonica 48CH presented resistance-inducing action by slowing down the disease progression up to 83% and decreasing the number of dead plants up to 90%. In vitro tests showed that the treatments Phosphorus 12CH, Phosphorus 48CH and Calcarea carbonica 48CH slowed down the mycelial growth. The latter also completely inhibited the production of sclerotia. These results indicate the potential of Phosphorus 12CH, Phosphorus 48CH, Calcarea carbonica 12CH, and Calcarea carbonica 48CH for controlling S. sclerotiorum in common beans.

Antimicrobial activity against Macrophomina phaseolina and the control of charcoal rot in soybeans using the homoeopathic drugs Sepia and Arsenicum album

Arq. Inst. Biol., v.84, 1-5, e0562016, 2017 RESUMO: O objetivo deste estudo foi avaliar o controle da podridão cinzenta da haste em soja, pulverizando soluções homeopáticas de Sepia e Arsenicum album, nas dinamizações 6, 12, 24, 36 e 48CH (centesimal hahnemaniana), bem como verificar a atividade antimicrobiana desses tratamentos contra Macrophomina phaseolina. Como tratamentos adicionais utilizou-se água destilada e solução hidroalcoólica a 30% de etanol. Foram realizados ensaios in vitro a fim de analisar o número de microescleródios e o crescimento micelial do fungo, e ensaios in vivo para acompanhar o progresso da doença e o tamanho da lesão. Para área abaixo da curva de crescimento micelial (AACCM), A. album não apresentou efeito, no entanto, Sepia reduziu em até 32% o crescimento. Para microescleródios não houve diferença estatística. Para área abaixo da curva de progresso da doença (AACPD), tanto Sepia quanto A. album na dinamização 24CH apresentaram redução de até 50% no primeiro ensaio e de até 70% no segundo ensaio quando comparados com a solução hidroalcoólica. Estes resultados indicam o potencial desses medicamentos homeopáticos no controle de podridão cinzenta da haste em soja.

Eliciadores proteicos e glicídicos de Adiantum capillus-veneris L. para fitoalexinas em sorgo Sorghum bicolor (L.) Moench

This study aimed to partially purify the compounds present in decoction of Adiantum capillus-veneris, which are efficient in the induction of phytoalexins in sorghum mesocotyl, by ammonium sulphate (AS) fractionation and gel filtration chromatography (GFC). The decoction of A. capillus-veneris at 1% (weight/volume) was precipitated with AS at the concentration of 0-20%, 20-40%, 40-60%, 60-80% and 80-100%, and these fractions were subjected to GFC. For the decoction not precipitated with AS, nine protein peaks and one carbohydrate peak were obtained with molecular weights ranging from 0.61 to 0.01 KDa. For the AS precipitation, we obtained: for the fraction 0-20%, two protein peaks (0.01 KDa) and two carbohydrate peaks with concentration of sugars ranging from 4.1 to 17.5 µg of sugar mL-1; for the 20-40%, three protein peaks (0.98 to 111.5 KDa) and five carbohydrate peaks (11.3 to 73.7 µg sugar mL-1); for the 40-60%, two protein peaks (0.09 to 111.5 KDa) and two carbohydrate peaks (5.6 to 7.5 µg of sugar mL-1); for the 60-80%, six protein peaks (lower than 0.02 KDa) and two carbohydrate peaks (16.5 to 51.3 µg of sugar mL-1); and for the 80-100%, three protein peaks with molecular weight equivalent to 0.09 KDa. The sorghum mesocotyls were treated with GFC fractions, decoction (1%), acibenzolar-S-methyl (ASM) (125 mg L-1 a.i. as elicitor reference) and sodium phosphate buffer (10 mM, pH 6.0). The protein peak II (0.09 KDa) from the decoction not precipitated was effective in inducing phytoalexin, exceeding in 6.68% the ASM. Among the fractions, the one with 60-80% of AS increased in 76% the induction of phytoalexin compared to ASM. According to the results, we could obtain protein and/or carbohydrate fractions capable of inducing phytoalexins in sorghum better than the decoction from which they are derived from, showing the potential of these molecules for future research studies on the induction of resistance.

Alternative management of root-knot nematodes (Meloidogyne incognita) in beans (Phaseolus vulgaris).

The bean diseases have been responsible for major yield losses. The root-knot caused by the nematode Meloidogyne have been highlighted in recent years, especially in the soybean growing regions. Thus the aim of this study was to evaluate the potential of induction of resistance by Trichoderma and plant extracts compared with chemical terbufos and water in controlling nematode galls. Thousand nematode larvae J2 were inoculated in the root system of each plant. The evaluation took place 60 days after inoculation. The use of terbufos was efficient, but with the entire load of environmental impact. Alternative treatments of applying Trichoderma to the soil and incorporation of crotalaria leaves in the ground exerted the greatest effect in reducing the severity of disease and pathogen in greenhouse conditions.