Atividade de quitinases e peroxidases em folhas de eucalipto em diferentes estágios de desenvolvimento após tratamento com acibenzolar-S-metil (ASM) e inoculação com Puccinia psidii
Carregando...
Data
2010-04-01
Autores
Boava, Leonardo P [UNESP]
Kuhn, Odair J
Pascholati, Sérgio F
Di Piero, Robson M
Furtado, Edson Luiz [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Fitopatologia
Resumo
Visando esclarecer alguns eventos bioquímicos durante o processo de infecção no patossistema Puccinia psidii x eucalipto, comparou-se o metabolismo relacionado à defesa em folhas em diferentes níveis de desenvolvimento, em clones (Eucalyptus grandis x E. urophylla) denominados VR e C0, com sessenta dias de idade, resistente e suscetível à ferrugem, respectivamente, determinando-se a atividade de peroxidases e quitinases. Cada tratamento foi composto de 4 repetições, em delineamento inteiramente casualizado, considerando: 2 clones, inoculados e não inoculados com P. psidii; pulverizados com acibenzolar-S-metil (ASM) e água destilada; representados pelo 1º, 2º e 4º pares de folha (com tamanho equivalente a 1/5, 2/5 e 4/5 do desenvolvimento foliar total, respectivamente). A coleta das folhas ocorreu em 4 períodos: 0, 24, 72 e 96 horas após a inoculação (HAI). Os resultados obtidos evidenciaram que apesar de apresentarem níveis superiores de atividade de quitinases e peroxidases, o efeito do ASM ou o efeito da P. psidii não alteraram a atividade dessas enzimas em folhas desenvolvidas (4º par) no decorrer do período. Alterações nos níveis das enzimas após a inoculação apenas foram observadas nas folhas em desenvolvimento (1º e 2º pares), evidenciando que a resposta à infecção foi acompanhada pela síntese dessas enzimas. Os maiores incrementos nas atividades enzimáticas ocorreram nas plantas do clone resistente 72 HAI e nas plantas do clone suscetível que foram tratadas previamente com ASM e posteriormente inoculadas com o P. psidii.
To elucidate some biochemical processes during infection in the pathosystem Puccinia psidii x eucalyptus, the defense metabolism in different-stage leaves was compared between rust-resistant and susceptible clones, respectively. In addition, chitinase and peroxidase activities were assayed. Each treatment consisted of 4 replicates, in a completely randomized design: 2 clones, inoculated and not inoculated with P. psidii; sprayed with acibenzolar-S-methyl (ASM) and distilled water; and represented by the 1st leaf pair (size equivalent to 1/5 total leaf development), 2nd pair (2/5 total development), and 4th pair (4/5 total leaf length). Leaves were harvested in 4 periods: 0, 24, 72 and 96 hours after inoculation. Results indicated that ASM treatment or P. psidii action led to higher chitinase and peroxidase activity level but did not alter the expression of these activities in developed leaves (4th pair) during the experiment. Alterations in enzyme levels after inoculation were only observed in developing leaves (1st and 2nd pairs), which suggests that the response to infection was concomitant to chitinase and peroxidase synthesis. The highest increases in enzymatic activities were observed in resistant clones at 72 hours after inoculation and in susceptible ones previously treated with ASM and later inoculated with the pathogen.
To elucidate some biochemical processes during infection in the pathosystem Puccinia psidii x eucalyptus, the defense metabolism in different-stage leaves was compared between rust-resistant and susceptible clones, respectively. In addition, chitinase and peroxidase activities were assayed. Each treatment consisted of 4 replicates, in a completely randomized design: 2 clones, inoculated and not inoculated with P. psidii; sprayed with acibenzolar-S-methyl (ASM) and distilled water; and represented by the 1st leaf pair (size equivalent to 1/5 total leaf development), 2nd pair (2/5 total development), and 4th pair (4/5 total leaf length). Leaves were harvested in 4 periods: 0, 24, 72 and 96 hours after inoculation. Results indicated that ASM treatment or P. psidii action led to higher chitinase and peroxidase activity level but did not alter the expression of these activities in developed leaves (4th pair) during the experiment. Alterations in enzyme levels after inoculation were only observed in developing leaves (1st and 2nd pairs), which suggests that the response to infection was concomitant to chitinase and peroxidase synthesis. The highest increases in enzymatic activities were observed in resistant clones at 72 hours after inoculation and in susceptible ones previously treated with ASM and later inoculated with the pathogen.
Descrição
Palavras-chave
Eucalyptus, ferrugem das mirtáceas, proteínas-RP, indução de resistência, Eucalyptus, rust of Myrtaceae, PR-proteins, induction of resistance
Como citar
Tropical Plant Pathology. Sociedade Brasileira de Fitopatologia, v. 35, n. 2, p. 124-128, 2010.