Evolução metabólica e potencial biotecnológico de jardins de fungo de formigas Attini avaliados por metatranscriptômica
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Data
2017-07-03
Autores
Kakazu, Sérgio [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Formigas cultivadoras de fungo pertencentes à subtribo Attina (subfamília Myrmicinae) caracterizam-se por apresentar um mutualismo obrigatório com fungos basidiomicetos, que elas cultivam nas câmaras de seus ninhos e utilizam como sua principal fonte de alimento e enzimas, notadamente polissacaridases. Entre as formigas Attina, cinco sistemas agrícolas foram identificados, cada um deles representando uma transição na evolução da fungicultura. Conhecer as enzimas responsáveis por esta bioconversão é importante tanto para estudos evolutivos quanto para prospecção em biotecnologia. No presente estudo, foram construídas bibliotecas de RNAm de dois fungos isolados, um do jardim da formiga Atta sexdens (agricultura das cortadeiras), outro do jardim da formiga basal Mycocepurus goeldii (agricultura basal), e de mais dois jardins de fungo de formigas Attina, Acromyrmex subterraneus (agricultura das cortadeiras) e Apterostigma sp. (agricultura de fungos corais), a fim de caracterizar enzimas responsáveis pela bioconversão de matéria vegetal fresca em açúcares redutores. Nossos resultados demonstram que todos os materiais estudados, exceto o jardim de Apterostigma sp., expressaram todas as enzimas necessárias para a degradação da celulose. O jardim de Apterostigma sp., aparentemente, possui um sistema celulolítico limitado a degradação da celulose do tipo amorfa. Nossos dados indicam que L. gongylophorus não sofreu perda na capacidade de degradar polissacarídeos recalcitrantes de parede celular ao longo da sua história evolutiva. Pelo contrário, L. gongylophorus apresentou um melhor potencial para a degradação da xilana quando comparado ao fungo mutualista de M. goeldii, representante da forma de agricultura basal. A diferença no número de enzimas CAZy observadas entre o fungo L. gongylophorus isolado e o jardim de A. subterraneus evidencia uma flexibilidade metabólica em resposta ao tipo de substrato utilizado pelo fungo. Entre os materiais analisados, o fungo L. gongylophorus isolado apresentou uma sistema enzimático mais completo para a degradação da biomassa vegetal, sendo portando o microrganismo mais promissor para a produção biotecnológica de açúcares fermentáveis.
Fungus-growing ants belonging to the subtribe Attina (subfamily Myrmicinae) are characterized by an obligatory mutualism with basidiomycete fungi which they grow into the chambers of their nests and use as the main source of food and enzymes, notably polysaccharidases. Among attinas, five agricultural systems have been identified, each representing a transition in the evolution of fungiculture. It is important to understand the enzymes responsible for this bioconversion both for evolutionary studies and for prospecting in biotechnology. In the present investigation, we built libraries of mRNA of two different isolated fungi, one from gardens of the leaf-cutter ant Atta sexdens (leaf-cutter agriculture) and another isolated from gardens of the basal ant Mycocepurus goeldii (lower agriculture), and two other fungal gardens of attina ants, Acromyrmex subterraneus (leaf-cutter agriculture) and Apterostigma sp. (coral fungus agriculture) in order to characterize enzymes which are responsible for the bioconversion of vegetal matter into reducing sugars. Our results demonstrate that all the analyzed materials, except the Apterostigma sp. garden, expressed all the enzymes necessary for the cellulose degradation. The Apterostigma sp. garden apparently has a cellulolytic system limited to the degradation of amorphous cellulose. Our data indicate that L. gongylophorus did not suffer any loss in the ability to degrade recalcitrant cell wall polysaccharides throughout their evolutionary history. In contrast, L. gongylophorus presented a better potential for degradation of xylan compared to the fungus of M. goeldii, representative of the lower agriculture. The observed difference between the numbers of CAZymes in the fungus L. gongylophorus isolated and the A. subterraneus garden shows a metabolic flexibility in response to the type of substrate used by the fungus. Among the analyzed materials, the fungus L. gongylophorus isolated presented a more complete enzymatic system for the degradation of the plant biomass, being the most promising microorganism for the biotechnological production of fermentable sugars.
Fungus-growing ants belonging to the subtribe Attina (subfamily Myrmicinae) are characterized by an obligatory mutualism with basidiomycete fungi which they grow into the chambers of their nests and use as the main source of food and enzymes, notably polysaccharidases. Among attinas, five agricultural systems have been identified, each representing a transition in the evolution of fungiculture. It is important to understand the enzymes responsible for this bioconversion both for evolutionary studies and for prospecting in biotechnology. In the present investigation, we built libraries of mRNA of two different isolated fungi, one from gardens of the leaf-cutter ant Atta sexdens (leaf-cutter agriculture) and another isolated from gardens of the basal ant Mycocepurus goeldii (lower agriculture), and two other fungal gardens of attina ants, Acromyrmex subterraneus (leaf-cutter agriculture) and Apterostigma sp. (coral fungus agriculture) in order to characterize enzymes which are responsible for the bioconversion of vegetal matter into reducing sugars. Our results demonstrate that all the analyzed materials, except the Apterostigma sp. garden, expressed all the enzymes necessary for the cellulose degradation. The Apterostigma sp. garden apparently has a cellulolytic system limited to the degradation of amorphous cellulose. Our data indicate that L. gongylophorus did not suffer any loss in the ability to degrade recalcitrant cell wall polysaccharides throughout their evolutionary history. In contrast, L. gongylophorus presented a better potential for degradation of xylan compared to the fungus of M. goeldii, representative of the lower agriculture. The observed difference between the numbers of CAZymes in the fungus L. gongylophorus isolated and the A. subterraneus garden shows a metabolic flexibility in response to the type of substrate used by the fungus. Among the analyzed materials, the fungus L. gongylophorus isolated presented a more complete enzymatic system for the degradation of the plant biomass, being the most promising microorganism for the biotechnological production of fermentable sugars.
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Palavras-chave
Attina, Jardins de fungo, Polissacarídeos vegetais, Enzimas CAZy, Mutualismo, Fungus gardens, Plant polysaccharides, CAZymes, Mutualism