Fungos sapróbios do semiárido nordestino: aspectos fisiológicos, ação no controle da ferrugem e indução de enraizamento em mudas de eucalipto
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2013-10-30
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Universidade Estadual Paulista (Unesp)
Resumo
O eucalipto é acometido por diversos patógenos, podendo dificultar o desenvolvimento habitual da planta. Um caso típico e atualmente frequente é a ferrugem do eucalipto, ocasionada pelo fungo fitopatogênico Puccinia psidii G. Winter, responsável por deformações em órgãos, perda de dominância apical e redução de crescimento das plantas. Sendo assim, o presente estudo teve como principal finalidade uma avaliação prospectiva da ação dos fungos sapróbios isolados do Semiárido Nordestino, na ativação de mecanismos latentes de resistência em mudas de eucalipto, de clone suscetível, contra a ação da P. psidii. Para tanto, realizaram-se testes fisiológicos com estes fungos, visando avaliar o crescimento micelial e a concentração de esporos em diferentes meios de cultura e temperaturas de incubação. Avaliou-se o potencial inibitório destes fungos na germinação de urediniósporos do agente causal da ferrugem. Nos testes in vivo, mudas de Eucalyptus do clone H13 foram inoculadas tanto com P. psidii, quanto com os possíveis indutores de resistência, visando avaliar a severidade da doença e determinar a atividade enzimática quando os indutores estão associados ao patógeno no hospedeiro. A ação dos sapróbios no potencial de enraizamento de miniestacas também foi avaliada. Os resultados mostraram que Phialomyces macrosporus apresentou indícios de ser um ótimo indutor biótico para a ferrugem inibindo germinação de urediniósporos de P. psidii, e aumentou a atividade das enzimas Fenilalanina amônia-liase, Peroxidase e β-1,3-glucanase. Outros fungos também apresentaram resultados promissores, como Curvularia eragrostidis que diminui a severidade da ferrugem e induziu enraizamento de estacas; Stachybotrys chartarum que diminuiu a severidade da ferrugem e aumentou a atividade da β-1,3-glucanase; e Curvularia inaequalis que aumentou a atividade da enzima Fenilalanina amônialias
Eucalyptus is affected by many pathogens, which may hinder the normal development of the plant. A typical case is the frequent and currently eucalyptus rust, caused by the plant pathogenic fungus Puccinia psidii G. Winter responsible for malformations in organs, loss of apical dominance and reduced plant growth. Thus, this study had as its main purpose a prospective assessment of the action of saprobe fungi isolated from the semiarid Northeast, the activation of latent resistance in seedlings of Eucalyptus clone susceptible, against the action of P. psidii. Therefore, we tested if physiological with these fungi, to evaluate the mycelial growth and spore concentration in culture media and incubation temperatures. We evaluated the inhibitory potential of these fungi on germination of urediniospores of the causal agent of rust. In in vivo tests, seedlings of Eucalyptus clone H13 were inoculated with either P. psidii as to the possible induction of resistance, to evaluate the severity of the disease and determine the enzymatic activity when the inductors are associated with the pathogen in the host. The action of saprobes in rooting potential of cuttings was also evaluated. The results showed that Phialomyces macrosporus showed signs of being a great biotic inducer for rust inhibiting germination of urediniospores of P. psidii, and increased the activity of the enzyme phenylalanine ammonia-lyase, peroxidase and β-1,3-glucanase. Other fungi also showed promising results, as Curvularia eragrostidis which decreases the severity of rust and induced rooting; Stachybotrys chartarum which reduced the disease severity and increased the activity of β-1,3-glucanase, and Curvularia inaequalis that increased activity the enzyme phenylalanine ammonialyase.
Eucalyptus is affected by many pathogens, which may hinder the normal development of the plant. A typical case is the frequent and currently eucalyptus rust, caused by the plant pathogenic fungus Puccinia psidii G. Winter responsible for malformations in organs, loss of apical dominance and reduced plant growth. Thus, this study had as its main purpose a prospective assessment of the action of saprobe fungi isolated from the semiarid Northeast, the activation of latent resistance in seedlings of Eucalyptus clone susceptible, against the action of P. psidii. Therefore, we tested if physiological with these fungi, to evaluate the mycelial growth and spore concentration in culture media and incubation temperatures. We evaluated the inhibitory potential of these fungi on germination of urediniospores of the causal agent of rust. In in vivo tests, seedlings of Eucalyptus clone H13 were inoculated with either P. psidii as to the possible induction of resistance, to evaluate the severity of the disease and determine the enzymatic activity when the inductors are associated with the pathogen in the host. The action of saprobes in rooting potential of cuttings was also evaluated. The results showed that Phialomyces macrosporus showed signs of being a great biotic inducer for rust inhibiting germination of urediniospores of P. psidii, and increased the activity of the enzyme phenylalanine ammonia-lyase, peroxidase and β-1,3-glucanase. Other fungi also showed promising results, as Curvularia eragrostidis which decreases the severity of rust and induced rooting; Stachybotrys chartarum which reduced the disease severity and increased the activity of β-1,3-glucanase, and Curvularia inaequalis that increased activity the enzyme phenylalanine ammonialyase.
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Palavras-chave
Eucalyptus grandis - Doenças e pragas, Plantas - Resistencia a doenças e pragas, Fungos-da-ferrugem, Fungos na agricultura, Fungi in agriculture
Como citar
PIEROZZI, Caroline Geraldi. Fungos sapróbios do semiárido nordestino: aspectos fisiológicos, ação no controle da ferrugem e indução de enraizamento em mudas de eucalipto. 2013. xi, 91 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Ciências Agronômicas de Botucatu, 2013.