Enzimas marcadoras de indução de resistência diferencialmente reguladas em soja resistente e suscetível à ferrugem-asiática-da-soja

Abstract

Resumo -O objetivo deste trabalho foi avaliar, por meio de enzimas marcadoras, a indução de resistência à ferrugem-asiática-da-soja em genótipos de soja contrastantes quanto à suscetibilidade a Phakopsora pachyrhizi. A proteína total e as atividades de cinco enzimas marcadoras da indução de resistência (lipoxigenases, peroxidases, fenilalanina amônia-liase, quitinases e β-1,3-glucanases) foram avaliadas em extratos de folhas de plantas de soja dos genótipos Embrapa 48 (suscetível) e PI 561356 (resistente), submetidas à inoculação ou não com o patógeno. Foram observadas respostas de defesa discrepantes entre os dois genótipos e entre os tempos de coleta (12, 72 e 168 horas após inoculação). A resposta de indução dessas enzimas assemelha-se à defesa bifásica, para Embrapa 48, e é consistente com o observado para outros patossistemas. No entanto, o genótipo PI 561356 respondeu com diminuição da concentração de proteína total e das atividades enzimáticas, o que indica redução do metabolismo geral das plantas infectadas. Há um importante mecanismo de resistência do genótipo PI 561356, ainda não relatado, embasado em vias que envolvem essas enzimas marcadoras e em mecanismos que utilizam menor concentração de proteínas, como os de via metabólica de resposta em cascata.Termos para indexação: Glycine max, Phakopsora pachyrhizi, atividade enzimática, mecanismos de defesa, resistência sistêmica, resposta em cascata. Differentially regulated induced resistance marker enzymes in soybean genotypes resistant and susceptible to Asian soybean rustAbstract -The objective of this work was to evaluate induced resistance to Asian soybean rust by means of enzyme activities in soybean genotypes contrasting as to their susceptibility to Phakopsora pachyrhizi. Total protein and the activities of five induced resistance marker enzymes (lipoxygenases, peroxidases, phenylalanine ammonia-lyase, chitinases and β-1,3-glucanases) were evaluated in leaf extracts of soybean plants of the genotypes Embrapa 48 (susceptible) and PI 561356 (resistant), inoculated or not with the pathogen. Discrepant defense responses were obtained between the two genotypes and among the leaf harvest times (12, 72, and 168 hours after inoculation). The induction response of these enzymes resembles the biphasic defense in Embrapa 48 and is consistent with that observed in other pathological systems. However, the genotype PI 561356 responded with a decrease in total protein concentration and in enzymatic activities, indicating a general reduction in the metabolism of the infected plants. There is an important mechanism of resistance for the genotype PI 561356, not yet reported, which is grounded on the metabolic ways involving these induced resistance marker enzymes and on the mechanisms that use lower concentrations of total protein, such as the ones with metabolic pathways in response cascade.

Phenylalanine ammonia lyase (PAL) activity in genotypes of Opuntia spp. against artificial infestation of Dactylopius opuntiae submitted to biotic and abiotic resistance inducers

“…Thus, research on the use of new resistance inducers has been developed in order to evaluate them as an alternative to traditional management. The activity of some enzymes of oxidative stress such as phenylalanine ammonia lyase, are considered markers of efficiency in the use of inductors (Almeida et al, 2012;Silva et al, 2018).…”

“…Phenylalanine ammonia lyase is considered an important marker of resistance induction in secondary plant metabolism (Almeida et al, 2012). This enzyme is the first in the phenylpropanoid pathway to eliminate ammonia from Lphenylalanine and produce trans-cinnamic acid.…”

“…Most work by modifying plant defence signalling pathways, but little is known about how chain reactions occur in signalling activation (Wang et al, 2020). One of the ways to verify the action of these inducers on plants is to verify the activity of some enzymes of oxidative stress, an example is phenylalanine ammonia lyase, which in certain amounts determine positive rates in the resistance of plants to attacks (Almeida et al, 2012). Resistance inducers act in defence and their responses can be elucidated through phenylalanine ammonia-lyase (Silva et al, 2018).…”

Frequency of Application of Salicylic Acid and Its Impact on Growth Aspects and Biochemical Quality In Lettuce Plants (Lactuca sativaL.)

“…Among the new forms of production are those aimed at compounds that may induce resistance to plants, such as salicylic acid (SA) (Monteiroet al, 2013). SA is a phenolic compound that occurs naturally in plants, playing an important role in regulating plant growth, development, maturation and defense responses (Almeida, 2012;Sánchez-Rangel et al,2015;Cueto-Ginzoa et al, 2016). In addition to the defense responses, SA acts in the response to abiotic stress, including drought, low temperature, salinity, among others.…”

“…Changes in the activities of some enzymes are important for the definition of the state of induced resistance in the presence of pathogens. Among these enzymes, the most important are: Phenylalanine Ammonia-Liase (PAL), peroxidases, chitinases, lipoxygenases and β-1,3-glucanases (Almeida, 2012).…”