Bioatividade de extratos de fungos da Antártica no combate a bacterioses da mandioca, tomate e pimentão causadas por Xanthomonas ssp.
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Data
2018-07-20
Autores
Fonseca, Mariana Gabriela [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Ainda que consideráveis avanços tecnológicos no setor agrícola tenham proporcionado melhorias no bem-estar humano, milhares de pessoas ainda enfrentam miséria e fome ao redor do mundo. O progresso alcançado no último século, com a Revolução Verde, apesar de ter impulsionado a produção global de alimentos, também trouxe consequências catastróficas para o ambiente natural. Além disso, a população mundial continua a crescer exponencialmente, em especial em regiões emergentes como nos continentes africano e asiático. Todos esses fatores, somados aos inúmeros limitantes das produções agrícolas, representam uma grande ameaça à segurança alimentar do planeta, além de trazer prejuízos econômicos exorbitantes. Dentre os limitantes agrícolas, as fitopatologias causadas por bactérias do gênero Xanthomonas respondem por perdas de produção que podem chegar a 100%, quando em situação epidêmica. As produções de tomate, pimentão e mandioca podem ser reduzidas gravemente quando acometidas por Xanthomonas euvesicatoria, causadora da mancha bacteriana em pimentão e tomateiros, e Xanthomonas axonopodis pv. manihotis, causadora da bacteriose da mandioca. O combate atual para estas doenças baseia-se no uso de compostos cúpricos, notadamente danosos à saúde humana e ambiental, mas há casos, como o da bacteriose da mandioca, em que não há controle químico eficaz, sendo medidas de controle e manejo a única possibilidade de amenizar o problema. Como alternativa, estudos vem apontado a possibilidade de uso de metabólitos secundários de microrganismos, incluindo fungos da Antártica, no combate às Xanthomonas ssp. A presente pesquisa avaliou o potencial bactericida de extratos produzidos por 156 fungos isolados de diversas amostras de solo e sedimentos marinhos antárticos contra X. euvesicatoria e X. ax. pv. manihotis. Vinte e sete extratos foram bioativos para pelo menos uma das espécies de Xanthomonas testadas. Os extratos bioativos foram produzidos por 23 diferentes fungos, sendo que 9 foram isolados de amostras de sedimentos marinhos, 5 de solo abaixo de madeira podre, 6 de solo com biofilme e 3 isolados de solo abaixo de barra de ferro. O gênero de fungos Pseudogymnoascus, bastante comum na Antártica, foi predominante dentre os isolados foram produtores de compostos bioativos contra as espécies testadas.
Yet considerable technological advances in the agricultural sector have provided improvements in human well-being, thousands of people still face misery and hunger around the world. The progress achieved in the last century within the Green Revolution, despite having boosted global food production, has also brought catastrophic consequences to the natural environment. In addition, the world population continues to grow exponentially, especially in emerging regions such as the African and Asian continents. All these factors, coupled with the numerous constraints of agricultural production, pose a great threat to the planet's food security, as well as exorbitant economic losses. Among the agricultural limitations, phytopathologies caused by bacteria of the genus Xanthomonas respond by losses of production that can reach 100%, when in an epidemic situation. The tomato, pepper and cassava productions can be severely reduced when affected by Xanthomonas euvesicatoria, which causes bacterial spot in pepper and tomatoes, and Xanthomonas axonopodis pv. manihotis, which causes cassava bacterial blight. The current fight for these diseases is based on the use of copper compounds, notably harmful to human and environmental health, but there are cases, such as cassava bacterial blight, in which there is no effective chemical control, and management measures are the only possibility of mitigating the problem. As an alternative, studies have indicated the possibility of using secondary metabolites of microorganisms, including Antarctic fungi, in the control of Xanthomonas ssp. The present study evaluated the bactericidal potential of extracts produced by 156 fungi isolated from several soil samples and marine sediments against X. euvesicatoria and X. ax. pv. manihotis. Twenty-seven extracts were bioactive for at least one of the Xanthomonas species tested. Bioactive extracts were produced by 23 different fungi, of which 9 were isolated from marine sediment samples, 5 from soil under rotten wood, 6 from soil with biofilm and 3 soil isolates below iron bar. The genus of fungi Pseudogymnoascus, very common in Antarctica, was predominant among the isolates were producers of bioactive compounds against the species tested.
Yet considerable technological advances in the agricultural sector have provided improvements in human well-being, thousands of people still face misery and hunger around the world. The progress achieved in the last century within the Green Revolution, despite having boosted global food production, has also brought catastrophic consequences to the natural environment. In addition, the world population continues to grow exponentially, especially in emerging regions such as the African and Asian continents. All these factors, coupled with the numerous constraints of agricultural production, pose a great threat to the planet's food security, as well as exorbitant economic losses. Among the agricultural limitations, phytopathologies caused by bacteria of the genus Xanthomonas respond by losses of production that can reach 100%, when in an epidemic situation. The tomato, pepper and cassava productions can be severely reduced when affected by Xanthomonas euvesicatoria, which causes bacterial spot in pepper and tomatoes, and Xanthomonas axonopodis pv. manihotis, which causes cassava bacterial blight. The current fight for these diseases is based on the use of copper compounds, notably harmful to human and environmental health, but there are cases, such as cassava bacterial blight, in which there is no effective chemical control, and management measures are the only possibility of mitigating the problem. As an alternative, studies have indicated the possibility of using secondary metabolites of microorganisms, including Antarctic fungi, in the control of Xanthomonas ssp. The present study evaluated the bactericidal potential of extracts produced by 156 fungi isolated from several soil samples and marine sediments against X. euvesicatoria and X. ax. pv. manihotis. Twenty-seven extracts were bioactive for at least one of the Xanthomonas species tested. Bioactive extracts were produced by 23 different fungi, of which 9 were isolated from marine sediment samples, 5 from soil under rotten wood, 6 from soil with biofilm and 3 soil isolates below iron bar. The genus of fungi Pseudogymnoascus, very common in Antarctica, was predominant among the isolates were producers of bioactive compounds against the species tested.
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Palavras-chave
Xanthomonas, Metabólitos secundários, Fungos, Antártica, Secondary metabolites, Fungi, Antarctica