RESUMO
Several endophytic fungi have been reported to have produced bioactive metabolites. Some of them, including the Induratia species, have the capacity to emit volatile compounds with antimicrobial properties with broad spectrum against human and plant pathogens. The present study aimed to prospect the Induratia species producing volatile organic compounds (VOCs), in carqueja plants used in alternative medicine and coffee plants in Brazil. A total of 11 fungal isolates producing volatile metabolites were obtained by a parallel growth technique, using I. alba 620 as a reference strain. Phylogenetic relationships revealed the presence of at least three distinct species, I. coffeana, I. yucatanensis, and Induratia sp. SPME/GC/MS analyses of the VOCs in the headspace above the mycelium from Induratia species cultured for 10 days on PDA revealed the volatile profile emitted by I. coffeana CCF 572, I. coffeana COAD 2055, I. yucatanensis COAD 2062, and Induratia sp. COAD 2059. Volatile organic compounds produced by I. coffeana isolates presented antimicrobial activity against Aspergillus ochraceus, A. sclerotiorum, A. elegans, A. foetidus, A. flavus, A. tamari, A. tubingensis, A. sydowii, A. niger, A. caespitosus, A. versicolor, and A. expansum, sometimes by decreasing the growth rate or, mainly, by fully inhibiting colony growth. Fifty-eight percent of the target species died after 6 days of exposure to VOCs emitted by I. coffeana CCF 572. In addition, VOCs emitted by the same fungus inhibited the growth in A. ochraceus inoculated into coffee beans, which indicates that plants which have I. coffeana as an endophyte may be protected from attacks by this plant pathogen.
Assuntos
Anti-Infecciosos , Coffea , Compostos Orgânicos Voláteis , Xylariales , Humanos , Compostos Orgânicos Voláteis/metabolismo , Brasil , Filogenia , Anti-Infecciosos/metabolismo , Xylariales/metabolismo , FungosRESUMO
The genus Gliocephalotrichum (Nectriaceae), originally described as a soil-borne fungus, has been associated with postharvest diseases, especially of tropical fruits. Taxonomic studies using both morphological and molecular phylogenetic analyses have contributed to recognition of novel species in several countries. However, in Brazil, only three isolates of Gliocephalotrichum have been collected from soil samples and roots since the late 1970s. Our study expands the sample range using many Gliocephalotrichum isolates obtained from rotting fruits of tropical plant species in different states of Brazil. Polyphasic taxonomy was assessed with phylogenetic analyses of DNA sequences from four nuclear loci, morphological comparisons, and pathogenicity tests. As a result, three known species (G. bulbilium, G. longibrachium, and G. simplex) were identified from new hosts and locations in Brazil. In addition, three new species are described-G. abrachium, G. brasiliense, and G. caryocaris. A key to all Gliocephalotrichum species worldwide is provided. Although species of Gliocephalotrichum have not been considered to be important plant pathogens, this study shows they may cause postharvest fruit rot in tropical fruits and therefore have an impact in communities that depend economically on the harvest and sale of these fruits.
Assuntos
Frutas/microbiologia , Hypocreales/classificação , Hypocreales/citologia , Hypocreales/genética , Filogenia , Doenças das Plantas , Raízes de Plantas/microbiologia , Anacardiaceae/microbiologia , Brasil , Garcinia/microbiologia , Malpighiales/microbiologia , Análise de Sequência de DNA , Microbiologia do SoloRESUMO
The use of extracts of algae in agriculture has been growing because of their benefits to plant development and production. The objective of this study was to evaluate the effects of Ascophyllum nodosum extract on the postharvest quality of Irati and Reubennel plums and on the incidence of brown rot. The treatments consisted of concentrations of 0, 0.1, 0.2, 0.3 and 0.4 mL L-1 of a commercial product containing algae extract (Algamare®) that were applied to the fruits by immersion. The fruits were then stored for 15 (cv. Irati) or 30 days (cv. Reubennel) at 2.5 °C and 90% RH and for two additional days at ambient conditions for further physicochemical analysis. A batch of Reubennel plums was inoculated with Monilinia fructicola and kept for seven days in a cold room and an additional nine days at room temperature to evaluate the occurrence of brown rot. The postharvest application of the extract at a concentration of 0.4 mL L-1 altered some of the physicochemical characteristics of the fruit after storage; an increase in the total phenolic compound content and PG activity were observed in Irati plums. Reubennel fruits had higher titratable acidity, a lower TSS/TA ratio, lower pulp firmness and higher PME activity. The most significant effect was observed with the application of A. nodosum extract at 0.4 mL L-1, which significantly reduced the incidence and severity of brown rot in the inoculated fruits and had a similar control effect as the application of the fungicide iprodione.(AU)
O uso de extratos de algas na agricultura vem crescendo devido aos benefícios no desenvolvimento e produção das plantas. O objetivo do estudo foi avaliar o efeito do extrato de Ascophyllum nodosum na qualidade pós-colheita de ameixas Irati e Reubennel e na incidência de podridão parda. Os tratamentos consistiram de concentrações de 0, 0,1, 0,2, 0,3 e 0,4 mL L-1 de produto comercial contendo extrato de algas (Algamare®) que foram aplicados por imersão nos frutos e posterior armazenamento por 15 (cv. Irati) ou 30 dias (cv. Reubennel) a 2,5 °C e 90% de UR e dois dias adicionais em condições ambiente, para posterior análises físico-químicas. Um lote de ameixas Reubennel foi inoculado com Monilinia fructicola, mantido por sete dias em câmara fria e mais nove dias à temperatura ambiente para avaliar a ocorrência de podridão parda. A aplicação pós-colheita do extrato com a dose de 0,4 mL L-1 alterou algumas características físico-químicas após o armazenamento, como o aumento no teor total de compostos fenólicos e a atividade da enzima PG para as ameixas Irati. Para a cv. Reubennel, os frutos apresentaram maior acidez titulável, menor relação SST/AT, menor firmeza de polpa e maior atividade da enzima PME. O efeito mais significativo foi verificado pela aplicação do extrato de A. nodosum a 0,4 mL L-1, que reduziu significativamente a incidência e a severidade da podridão parda em frutos inoculados, com controle semelhante à aplicação do fungicida iprodione.(AU)
Assuntos
Prunus domestica/efeitos dos fármacos , Prunus domestica/crescimento & desenvolvimento , AscophyllumRESUMO
The use of extracts of algae in agriculture has been growing because of their benefits to plant development and production. The objective of this study was to evaluate the effects of Ascophyllum nodosum extract on the postharvest quality of Irati and Reubennel plums and on the incidence of brown rot. The treatments consisted of concentrations of 0, 0.1, 0.2, 0.3 and 0.4 mL L-1 of a commercial product containing algae extract (Algamare®) that were applied to the fruits by immersion. The fruits were then stored for 15 (cv. Irati) or 30 days (cv. Reubennel) at 2.5 °C and 90% RH and for two additional days at ambient conditions for further physicochemical analysis. A batch of Reubennel plums was inoculated with Monilinia fructicola and kept for seven days in a cold room and an additional nine days at room temperature to evaluate the occurrence of brown rot. The postharvest application of the extract at a concentration of 0.4 mL L-1 altered some of the physicochemical characteristics of the fruit after storage; an increase in the total phenolic compound content and PG activity were observed in Irati plums. Reubennel fruits had higher titratable acidity, a lower TSS/TA ratio, lower pulp firmness and higher PME activity. The most significant effect was observed with the application of A. nodosum extract at 0.4 mL L-1, which significantly reduced the incidence and severity of brown rot in the inoculated fruits and had a similar control effect as the application of the fungicide iprodione.
O uso de extratos de algas na agricultura vem crescendo devido aos benefícios no desenvolvimento e produção das plantas. O objetivo do estudo foi avaliar o efeito do extrato de Ascophyllum nodosum na qualidade pós-colheita de ameixas Irati e Reubennel e na incidência de podridão parda. Os tratamentos consistiram de concentrações de 0, 0,1, 0,2, 0,3 e 0,4 mL L-1 de produto comercial contendo extrato de algas (Algamare®) que foram aplicados por imersão nos frutos e posterior armazenamento por 15 (cv. Irati) ou 30 dias (cv. Reubennel) a 2,5 °C e 90% de UR e dois dias adicionais em condições ambiente, para posterior análises físico-químicas. Um lote de ameixas Reubennel foi inoculado com Monilinia fructicola, mantido por sete dias em câmara fria e mais nove dias à temperatura ambiente para avaliar a ocorrência de podridão parda. A aplicação pós-colheita do extrato com a dose de 0,4 mL L-1 alterou algumas características físico-químicas após o armazenamento, como o aumento no teor total de compostos fenólicos e a atividade da enzima PG para as ameixas Irati. Para a cv. Reubennel, os frutos apresentaram maior acidez titulável, menor relação SST/AT, menor firmeza de polpa e maior atividade da enzima PME. O efeito mais significativo foi verificado pela aplicação do extrato de A. nodosum a 0,4 mL L-1, que reduziu significativamente a incidência e a severidade da podridão parda em frutos inoculados, com controle semelhante à aplicação do fungicida iprodione.
Assuntos
Ascophyllum , Prunus domestica/crescimento & desenvolvimento , Prunus domestica/efeitos dos fármacosRESUMO
The increased demand for pesticide-free foods has also increased the search for healthier and environmentally friendly alternatives in agriculture. Essential oils are known to possess natural antifungal properties, becoming a reliable alternative for commercial fungicides, especially for postharvest decay control. However, essential oils are volatile and photodegradable, which reduces their long-term activities. This work presents the development of a lemongrass essential oil-containing poly(lactic acid) nanocapsules. They have shown in vitro antifungal activity against Colletotrichum acutatum and Colletotrichum gloeosporioides with a MIC dosage of 0.1% (v/v) for both phytopathogens. In the in vivo assay with postharvest apples, the ones treated with encapsulated essential oil showed bitter rot lesions three times smaller than the ones treated with non-encapsulated essential oil, or in comparison to the apples in positive control. The methodology led to stable nanocapsules with spherical morphology, a mean diameter of 96.4 nm, and with an encapsulation efficiency of 99%.
Assuntos
Antifúngicos/farmacologia , Colletotrichum/efeitos dos fármacos , Cymbopogon/química , Fungicidas Industriais/farmacologia , Nanocápsulas/química , Óleos Voláteis/química , Poliésteres/farmacologia , Malus/efeitos dos fármacos , Malus/microbiologia , Poliésteres/químicaRESUMO
The aim of the present work was to evaluate the ability of the native yeast Rhodosporidium fluviale to control Botrytis cinerea on apple fruit and to study the possible mechanisms of action with the goal of improving the control of gray mold. For this, the influence of application time of the yeast was studied simulating preventive and curative effects. Also, the effect of nonviable cells of the yeast in the biocontrol was assessed. According to the results obtained, the following mechanisms of action of R. fluviale could be proposed: 1- competition for space, 2- direct interaction between antagonist and pathogen, 3- induction of ß-1,3-glucanase in apple tissue, 4- Probable production of glucanase in the apple wounds and 5- antifungal action of cellular components, probably chitin, present in the wall of yeast cells that could be the explanation for the activity of nonviable cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Significance and Impact of the Study: Botrytis cinerea Pers: Fr, which causes gray mold of fruits and vegetables around the world, is difficult to control successfully because it is genetically variable and rapidly develops resistance to the chemicals commonly used for its control. This study is a contribution to the biocontrol of this phytopathogen fungus. The evaluation of the native yeast Rhodosporidium fluviale as biocontrol agent and the elucidation of possible mechanisms of action, including the participation of nonviable cells of this yeast, have not been reported up to date.
Assuntos
Antibiose/fisiologia , Antifúngicos/metabolismo , Basidiomycota/metabolismo , Agentes de Controle Biológico/metabolismo , Botrytis/crescimento & desenvolvimento , Malus/microbiologia , Argentina , Frutas/microbiologia , Doenças das Plantas/microbiologiaRESUMO
Yeasts are some of the most important postharvest biocontrol agents. Postharvest oranges frequently deteriorate due to green mould (Penicillium digitatum), which causes significant losses. The aims of this study were to determine the composition and diversity of yeasts on plants of the Brazilian Cerrado and to explore their potential for inhibiting citrus green mould. Leaves and fruit of Byrsonima crassifolia and Eugenia dysenterica were collected from Cerrado conservation areas, and thirty-five yeasts were isolated and identified by sequencing the D1-D2 domain of the rDNA large subunit (26S). The isolates represented the Aureobasidium, Meyerozyma, Candida, and Pichia genera. Three isolates identified as Aureobasidium pullulans exhibited potential for the control of P. digitatum in both in vitro and in vivo tests; these isolates reduced the incidence of disease and increased the storage time of fruit. Aureobasidium. pullulans has immense potential for the biological control of filamentous fungi.