Abstract Polysaccharides from fungal wastes were partially characterized and evaluated for their protective effects against bacterial spot caused by Xanthomonas gardneri on four tomato cultivars: Santa Cruz Kada, Natália, BRS Sena and Forty. The polysaccharides were extracted from spent mushroom substrate of Pleurotus ostreatus, residual brewery yeast (Saccharomyces cerevisiae), and basidiocarps discarded from Lentinula edodes production. These polysaccharides were characterized for total carbohydrates, phenolics and proteins content, pH, scatter intensity, conductivity, Zeta potential, DPPH scavenging assay and infrared spectroscopy. The effects of time interval between treatment and inoculation (4 or 7 days) and polysaccharide concentrations (0.5 or 1.5 mg.mL–1) were assessed for disease severity using a susceptible tomato cultivar. The polysaccharide action mode was investigated by determining the activity of peroxidases and phenylalanine ammonialyase and by quantifying flavonoids and total phenolics in the plants treated and challenged with X. gardneri. The polysaccharides obtained from Lentinula edodes (PSHII), Saccharomyces cerevisiae (PRC) and Pleurotus ostreatus (PSPO) (1.5 mg.mL-1) reduced bacterial spot severity by 50% on tomato cotyledons, leaflets and five-leaf plants. Furthermore, PRC and PSHII (1.5 mg.mL–1) could decrease disease severity in all tested cultivars. PSHII, the most effective, did not cause change in phenylalanine ammonia-lyase activity or flavonoid content on the cultivars Kada and Natália. However, an increase in peroxidase activity and total phenol content on cv. Kada was noted. The polysaccharides obtained from food industry wastes could provide protection against bacterial spot on tomato cultivars by inducing defense mechanisms and can be useful in formulating products with phytosanitary potential.

Abstract Apple is one of the most important temperate fruit to Brazil economy, and the use of synthetic chemicals has been the main method for reducing postharvest diseases, such as the blue mold, caused by Penicillium expansum. This work intends to evaluate the practical utilization of chitosan for blue mold control. For this purpose, fruits were treated in a preventive and curative way, immersing the fruits in chitosan solution (5 or 10 mg mL-1), or adding a single drop of this solution (10 mg mL-1) directly into the injuries. The eradicative effect of the polysaccharide was also evaluated in vitro and in vivo. Chitosan did not show a curative effect against the blue mold, and its eradicative effect was only evidenced on the higher concentration (10 mg mL-1). On the other hand, preventively, without the addition of adjuvants, chitosan reduced blue mold incidence in fruits by 24% and 93%, through the immersion or the single drop methods, respectively. Thus, it was found that, for long scale utilization, some improvements in the physico-chemical properties of the chitosan are needed, since it was only capable to prevent the infection by P. expansum when directly added on the fruit injury.

O objetivo deste estudo foi avaliar a atividade antimicrobiana dos extratos aquosos de corpos de frutificação de diferentes isolados de Lentinula edodessobre os patógenos Colletotrichum sublineolum, agente causal da antracnose em sorgo e em Xanthomonas axonopodispv. passiflorae, agente causal da mancha bacteriana em maracujá. Os resultados mostraram que os extratos aquosos dos isolados LE JAB - K e LE 95/ 01 reduziram significativamente a germinação de esporos de C. sublineolum,enquanto que o isolado LE 96/22 foi o único a inibir o crescimento micelial do patógeno. No entanto, todos os isolados de L. edodesmostraram efeito inibitório na formação de apressórios por C. sublineolum. Quanto a X. axonopodispv. passiflorae, os extratos aquosos obtidos de todos os isolados do cogumelo reduziram significativamente a multiplicação in vitroda bactéria. No entanto, a atividade antimicrobiana foi perdida quando os extratos foram autoclavado demonstrando assim a propriedade termolábil dos mesmos. O extrato aquoso do isolado LE 96/22 também foi parcialmente purificado por cromatografia de troca aniônica e a fração V exibiu elevada atividade inibitória sobre o crescimento micelial in vitrode C. sublineolum, enquanto que a multiplicação de X. axonopodispv. passifloraefoi inibida pelas frações IV, V e VII. Desta forma, demonstrou-se que os isolados de L. edodesproduzem compostos que apresentam atividade antifúngica e antibacteriana contra fitopatógenos, que estão principalmente concentrados na fração V.

The aim of this study was to evaluate the antimicrobial activity of aqueous extracts from fruiting bodies of different isolates of Lentinula edodeson the pathogens Colletotrichum sublineolum, the causal agent of anthracnose in sorghum, and Xanthomonas axonopodispv. passiflorae, the causal agent of bacterial spot in passion fruit. Results showed that the aqueous extracts from isolates LE JAB-K and LE 95/01 significantly reduced C. sublineolumspore germination,while the isolate LE 96/22 was the only one to inhibit the pathogen mycelial growth. However, all L. edodesisolates showed inhibitory effect on C. sublineolumappressorium formation. Regarding X. axonopodispv. passiflorae, the aqueous extracts from all L. edodesisolates significantly reduced the in vitromultiplication of the bacterium. However, antimicrobial activity was lost when the extracts were autoclaved, demonstrating their thermolabile property. The aqueous extract from isolate LE 96/22 was also partially purified by anion exchange chromatography and fraction V exhibited high inhibitory activity on the in vitromycelial growth of C. sublineolum, while the multiplication of X. axonopodispv. passifloraewas inhibited by fractions IV, V and VII. Thus, L. edodesisolates were shown to produce compounds exhibiting antifungal and antibacterial activities against phytopathogens, which are mainly concentrated in fraction V.

Bacterial spot, caused by Xanthomonas gardneri, is a disease of great importance for tomato crops, especially due to yield reduction. The objective of this study was to evaluate the effectiveness of low - and high-density chitosan for the control of bacterial spot and whether such control was due to activation of defense mechanisms in tomato. Tomato plants were treated with high-density (HD; 0.8 g/cm³) or low-density chitosan (LD; 0.4 g/cm³) at concentrations ranging from 0.0 to 3.0 mg/mL, and then inoculated with a bacterial suspension three days later. The effect of varying intervals (7, 5, 3 and 1 day) between the application of HD chitosan (3 mg/mL) and the inoculation of the pathogen was also assessed. The effect of chitosan on the in vitro growth of X. gardneri and the activities of peroxidases and polyphenol oxidases in leaves were also determined. HD chitosan (3.0 mg/mL) was able to greatly reduce disease severity by up to 85% compared to the control. The application of HD-chitosan at five days before inoculation showed larger reduction in disease severity and high level of peroxidase activity. The in vitro growth of X. gardneri was not affected by the treatment with chitosan, thus suggesting that the disease was controlled due to mechanisms related to induced resistance.

O bolor azul (Penicillium expansum) e o mofo cinzento (Botrytis cinerea) causam perdas significativas em pós-colheita de frutos de maçã. Como alternativa de controle, avaliou-se o efeito da fumigação de ácido acético, acetaldeído, benzaldeído, d-limoneno, timol, metil jasmonato e álcool etílico nas concentrações de 8 e 15 µL/L de ar sobre a germinação de esporos e sobre a incidência e a severidade dessas podridões em maçãs 'Fuji'. A germinação de esporos foi avaliada em lâminas escavadas, dispostas no interior de caixas plásticas, onde um agente fumigante atuou durante 60 min. Com microscópio ótico, observou-se, 24 h depois, que o ácido acético a 8 µL/L de ar inibiu totalmente a germinação de esporos de P. expansum, enquanto limoneno, timol, benzaldeído e metil jasmonato reduziram-na parcialmente. Apenas ácido acético e benzaldeído apresentaram efeito inibitório sobre B. cinerea. Nos testes in vivo, a fumigação ocorreu em caixas plásticas contendo quatro frutos previamente inoculados por parcela. Ácido acético reduziu a incidência de bolor azul e de mofo cinzento em 44% e 100%, respectivamente, a 8 µL/L de ar, porém causou fitotoxidez nos frutos, mostrando potencial uso para a redução de inóculo de Penicillium e Botrytis, principalmente na desinfestação das câmaras.

Blue mold (Penicillium expansum) and gray mold (Botrytis cinerea) cause significant post-harvest losses of apple fruit. As a control alternative, the effects of fumigation with acetic acid, acetaldehyde, benzaldehyde, d-limonene, thymol and methyl jasmonate, at 8 and 15 µL/L of air, on the germination of spores and the incidence and severity of blue and gray mold in 'Fuji' apples were evaluated. The germination of spores was evaluated in excavated slides arranged onto plastic boxes, where the fumigant agent acted for 60 min. With optical microscopy, it was observed after 24 h that acetic acid at 8 µL/L completely inhibited spore germination of P. expansum, while limonene, thymol, benzaldehyde and methyl jasmonate partially reduced it. Only acetic acid and benzaldehyde showed an inhibitory effect on B. cinerea. In in vivo tests, fumigation was conducted in plastic boxes containing four previously inoculated fruits per plot. Acetic acid reduced the incidence of blue mold and gray mold by 44% and 100%, respectively, at 8 µL/L of air. However, it caused phytotoxicity on fruits, indicating a potential use for reduction of inoculum of Botrytis and Penicillium in the disinfestation of chambers.

Verificou-se o efeito de indutores de resistência bióticos e abióticos nas atividades de quitinase e peroxidase e na redução da severidade da ferrugem do eucalipto causada por Puccinia psidii. Para isso, mudas de dois clones de eucalipto (Eucalyptus grandis x E. urophylla) denominados VR e C0, com sessenta dias de idade, mantidas em casa de vegetação, receberam tratamentos com Bion® (Acibenzolar-S-metil-ASM), Agro-Mos®, Dipel®, Ecolife40®, Crop-set® e uma preparação obtida a partir de Saccharomyces cerevisiae, 5 dias antes da inoculação com o patógeno. Uma suspensão de uredósporos de P. psidii, coletados a partir de plantas naturalmente infectadas, foi calibrada para 5 x 10(4) uredósporos/ mL. A inoculação foi realizada na face abaxial das folhas e a avaliação se deu 15 dias após, estimando-se a severidade da doença por meio de escala de notas. Os tratamentos ASM, preparado de S. cerevisiae e Ecolife® apresentaram os melhores resultados de controle da doença e os demais tratamentos não se mostraram eficazes para o controle. O aumento de atividade das enzimas quitinase e peroxidase foi observado em ambos os clones, previamente tratados com os indutores(ASM e S. cerevisiae), 48 horas após a inoculação com o fungo.

This study was aimed at verifying the effect of biotic and abiotic resistance inducers on the activities of chitinase and peroxidase as well as on the reduction of rust caused by Puccinia psidii in eucalyptus. Thus, seedlings of two 60-day eucalyptus clones were kept in a greenhouse and treated with Bion® (Acibenzolar-S-methyl, ASM), Agro-Mos®, Saccharomyces cerevisiae, Dipel®, Ecolife 40®, and Crop-set®, at 5 days before the pathogen inoculation. A suspension of P. psidii uredospores, collected from naturally infected plants, was adjusted to 5 x 10(4) uredospores/mL. Inoculation was carried out onto the dorsal leaf surface and 15 days later the disease severity was assessed according to a grading scale. ASM, S. cerevisiae and Ecolife treatments presented the best results for disease control, and the remaining treatments were not effective. Chitinase and peroxidase activity assay only included the two first treatments (ASM and S. cerevisiae). The increase in the activity of these enzymes was observed at 48 hours after the fungus inoculation in both clones previously treated with inducers.

O endurecimento dos frutos do maracujazeiro, causado pelo Cowpea aphid-borne mosaic virus (CABMV), é um dos problemas mais sérios que atingem a cultura. Tentativas de se obter plantas resistentes ao vírus ou estirpes fracas premunizantes não apresentaram sucesso até o momento. O objetivo do presente estudo foi o de avaliar a proteção das plantas de maracujá contra o CABMV, utilizando preparações dos cogumelos Lentinula edodes e Agaricus blazei, através da indução de resistência. Em experimentos conduzidos no interior de casa de vegetação, os extratos de basidiocarpos de ambos os cogumelos reduziram significativamente a incidência da virose em plantas de maracujá que tiveram as folhas pré-tratadas com esses extratos e que foram posteriormente inoculadas mecanicamente com o CABMV. No entanto, os extratos não protegeram as plantas em experimentos envolvendo a transmissão do CABMV pelo afídeo-vetor. O efeito inibidor dos extratos foi confirmado inoculando-se Chenopodium quinoa com uma mistura de extratos e suspensão viral. Ainda em C. quinoa, um hospedeiro de lesão local do CABMV, os extratos de alguns isolados dos cogumelos induziram resistência sistêmica contra o vírus. Os resultados mostram que os extratos aquosos de basidiocarpos de L. edodes e A. blazei contêm substâncias inibidoras da infectividade do CABMV, mas isso não é o suficiente para o controle pleno da virose em plantas de maracujá, considerando que elas são infectadas através de um vetor.

The objective of the present study was to evaluate the protection of passion fruit plants against CABMV by using preparations from Agaricus brasiliensis and Lentinula edodes mushrooms. In experiments carried out in the greenhouse, the fruiting body extracts from some of the isolates of both mushrooms significantly reduced CABMV incidence in passion fruit plants. This protective effect occurred when the plant leaves, pre-treated with extracts, were later inoculated mechanically with the virus. However, the extracts did not protect the plants in experiments involving CABMV transmission by aphid vectors. An inhibitory effect of mushroom extracts on the virus particles was also demonstrated on Chenopodium quinoa, a CABMV local lesion host, by inoculating the plants with a mixture of extracts and virus suspension. Still in C. quinoa, the mushroom extracts from some isolates induced systemic resistance against the virus. These results showed that aqueous extracts from A. brasiliensis and L. edodes fruiting bodies had CABMV infectivity inhibitors, but that was not enough to control the viral disease on passion fruit plants at all, considering they were infected through a vector.

Lentinula edodes (cogumelo "shiitake") é um fungo basidiomiceto que apresenta propriedades nutricionais, medicinais e antibióticas. Compostos de interesse para o homem têm sido isolados do basidiocarpo e dos filtrados de cultura obtidos a partir do crescimento micelial. O presente trabalho teve como objetivos avaliar o efeito de diferentes preparações de L. edodes sobre patógenos da cultura do sorgo, Exserohilum turcicum e Colletotrichum sublineolum, bem como a proteção das plantas de sorgo contra estes patógenos. Em testes com placas de Petri e lâminas de vidro para microscopia, extratos aquosos obtidos do basidiocarpo inteiro e de suas partes individualizadas, píleo e estipe, reduziram a taxa de crescimento micelial e inibiram a germinação de esporos dos fungos, enquanto a atividade antifúngica do filtrado de crescimento micelial foi menos pronunciada. Em mesocótilos de sorgo, as diferentes preparações do "shiitake" não provocaram o acúmulo de fitoalexinas. O extrato aquoso do basidiocarpo e o composto lentinana reduziram parcialmente a severidade das doenças provocadas por E. turcicum na cv. Brandes e por C. sublineolum na cv. Tx-398-B, quando pulverizados 48 horas antes da inoculação das plantas, sob condições de casa de vegetação. Portanto, L. edodes apresenta potencial como agente de controle biológico ou como um modelo para a síntese de substâncias fungicidas.

Lentinula edodes ("shiitake" mushroom) is a fungus that presents nutritional, medicinal and antibiotic properties. Valuable compounds have been isolated from the fruiting bodies and from mycelium growth filtrates. The present work had as objectives the evaluation of the effect of L. edodes preparations on two sorghum pathogens, Exserohilum turcicum and Colletotrichum sublineolum, as well as the protection of sorghum plants against those fungi. When in vitro studies were carried out, aqueous extracts from the whole fruiting bodies and also from fruiting body parts, cap and stem, reduced the mycelium growth and the spore germination of the plant pathogens, while the antifungal activity of L. edodes´s mycelium growth filtrate was less pronounced. The shiitake preparations did not induce phytoalexin accumulation in sorghum mesocotyls. Aqueous extracts from fruiting bodies and lentinan partially reduced disease severity caused by E. turcicum in the cv. Brandes and by C. sublineolum in the cv. Tx-398-B, when applied 48 hours before plant inoculation. Therefore, L. edodes exhibits potential as a biological control agent or as a model for the synthesis of fungicidal compounds.

O objetivo deste trabalho foi avaliar a aplicação de quitosana no controle da podridão-amarga da maçã em pós-colheita e seus efeitos sobre Colletotrichum acutatum e a atividade da peroxidase nos frutos. Frutos previamente infectados com o patógeno foram imersos em suspensões de quitosana com diferentes concentrações e pHs. Para estudar possíveis mecanismos de ação envolvidos no controle da doença, foram realizados testes in vitro, para avaliar o efeito da quitosana sobre a germinação de conídios de C. acutatum e sobre o crescimento micelial. Foi avaliada a capacidade da quitosana de induzir a síntese de enzimas relacionadas à defesa da planta (peroxidases), por meio de ensaio espectrofotométrico. Houve efeito de doses e de pH da quitosana sobre a redução da severidade da podridão-amarga em maçã. A suspensão de quitosana a 10 g L-1 e pH 4 foi a mais apropriada tecnicamente para o controle da doença, pois reduziu a severidade em 26%. O polissacarídeo não elevou a atividade de peroxidases nos frutos, mas reduziu a germinação de conídios e o crescimento micelial do patógeno. A quitosana aplicada em pós-colheita é uma medida alternativa aos fungicidas para o manejo da podridão-amarga.

The objective of this work was to evaluate the aplication of chitosan on the control of apple bitter rot in postharvest conditions and its effects on Colletotrichum acutatum and fruit peroxidase activity. Apple fruit previously infected with the pathogen were immersed in chitosan suspensions with different concentrations and pHs. To study some possible action mechanisms, in vitro tests were carried out to evaluate the effect of chitosan on spore germination and mycelial growth of C. acutatum. The capacity of chitosan to induce the synthesis of defense enzymes (peroxidases) was evaluated in fruits by spectrofotometric assay. Different doses and pH of chitosan were found to be effective in the reduction of the disease severity. Chitosan at 10 g L-1 (pH 4) had the most technical viability for the control of the disease and reduced the severity in 26%. Considering the action mechanisms, chitosan did not increase peroxidase activity in the fruits; however, it reduced both spore germination and mycelial growth of the pathogen. Chitosan applied at postharvest is an alternative to reduce bitter rot severity.

O objetivo deste trabalho foi avaliar o controle da antracnose em feijoeiro-comum pela aplicação de quitosana. A quitosana foi pulverizada em plantas de feijão-comum, em diferentes concentrações, no estádio V3, em casa de vegetação. As plantas foram também submetidas à inoculação de Colletotrichum lindemuthianum. A dose de 9 mg de quitosana por planta propiciou redução em mais de 50% na severidade da antracnose e não causou fitotoxicidade. O efeito protetor foi local e mais intenso no intervalo de tempo de 4 dias entre tratamento e inoculação. Observou-se redução significativa no crescimento micelial e inibição total da germinação de esporos de C. lindemuthianum, quando se utilizou o polissacarídeo a 1 mg mL-1 e 80 µg mL-1, respectivamente. Em folhas do feijoeiro, a quitosana provocou o aumento na atividade de glucanase. Quitosana apresenta propriedades antifúngicas contra C. lindemuthianum, bem como potencial para induzir resistência à planta, e pode ser uma alternativa para o controle da antracnose do feijoeiro.

The objective of this work was to evaluate the effect of chitosan on common bean (Phaseolus vulgaris) anthracnose. Different concentrations of chitosan suspension were sprayed on plants at V3 stage, in greenhouse; plants were also infected with Colletotrichum lindemuthianum. The concentration of 9 mg per plant reduced the anthracnose severity in more than 50%, without causing any toxic effect on bean plants. The protecting effect was local and more intense in a time interval of 4 days between treatment and inoculation. Mycelium growth reduction and spore germination inhibition of C. lindemuthianum were observed, when chitosan was used at 1 mg mL-1 and 80 µg mL-1, respectively. Chitosan increased the glucanase activity in bean leaves. Chitosan presents antifungal properties against C. lindemuthianum, as well as potential to induce resistance on bean plants. Therefore, the plant spraying with chitosan can be an alternative to control anthracnose.