Reguladores vegetais modulam a síntese de alcaloides e o perfil de voláteis foliares em mudas de Annona emarginata (Annonaceae)?
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Data
2020-02-19
Autores
Sousa, Marília Caixeta
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Universidade Estadual Paulista (Unesp)
Resumo
As plantas da família Annonaceae são conhecidas por produzirem diversos metabolitos especializados, dentre eles, alcaloides e voláteis de interesse farmacológico. No entanto, não há relatos de como seu metabolismo especializado (ME) pode responder a aplicação exógena de reguladores vegetais e como é possível a modulação ser associada ao metabolismo primário (MP). Assim, o objetivo deste trabalho foi avaliar as respostas do ME e MP de Annona emarginata em função da aplicação dos reguladores vegetais. Para isso plantas jovens foram tratadas com auxina, metil jasmonato, ácido salicílico e ácido abscísico em várias concentrações. Para conhecer o efeito particular da auxina foi realizado um segundo experimento que utilizou a auxina e seu inibidor observando a resposta em vários momentos após a aplicação. As respostas avaliadas do ME foram a quantificação dos alcaloides totais, da oxoaporfina liriodenina, perfil de alcaloides em raízes e o perfil de voláteis foliares. Para o MP foram determinadas as variáveis de trocas gasosas e fluorescencia da clorofila a. O uso de reguladores vegetais em A. emarginata apresentou efeito negativo nas variáveis de trocas gasosas, ocasionando diminuição da assimilação de CO2 e eficiência de carboxilação da enzima Rubisco. A aplicação de auxina a 10-6 M e do ácido salicílico a 10-3 M ocasionou incremento de alcaloides totais e liriodenina. Todos os reguladores alteraram a composição dos voláteis foliares, sendo que a auxina, metil jasmonato e ácido salicílico diminuiram a proporção relativa de monoterpenos, e o ácido abscísico provocou alterações nos sesquiterpenos. Com isso foi possível demonstrar que A. emarginata altera o fluxo energético entre metabolismo primário e especializado em função do regulador vegetal aplicado e que o número e proporção de metabolitos especializados também são modulados de acordo com o tratamento empregado.
Plants of the Annonaceae family are known to produce several specialized metabolites, including alkaloids and volatiles of pharmacological interest. However, there are no reports on how its specialized metabolism (SM) can respond to exogenous application of plant regulators and how it is possible that modulation is associated with primary metabolism (PM). Thus, the objective of this work was to evaluate the SM and PM responses of Annona emarginata as a function of the application of plant growth regulators. For this, young plants were treated with auxin, methyl jasmonate, salicylic acid and abscisic acid at various concentrations. To know the effect of auxin, a second experiment was carried out using auxin and its inhibitor, observing the response at various times after application. The evaluated responses of the SM were the quantification of the total alkaloids, the oxoaporphine liriodenine, the alkaloids profile in roots and the leaf volatiles profile. For PM, the gas exchange and fluorescence variables of chlorophyll a were determined. The use of plant growth regulators in A. emarginata had a negative effect on gas exchange variables, causing a decrease in CO2 assimilation and Rubisco enzyme carboxylation efficiency. The application of 10-6 M auxin and 10-3 M salicylic acid caused an increase in total alkaloids and liriodenine. All regulators altered the composition of leaf volatiles, with auxin, methyl jasmonate and salicylic acid decreasing the relative proportion of monoterpenes, and abscisic acid caused alterations in sesquiterpenes. Thus, it was possible to demonstrate that A. emarginata alters the energy flow between primary and specialized metabolism as a function of the plant growth regulator applied and that the number and proportion of specialized metabolites are also modulated according to the treatment used.
Plants of the Annonaceae family are known to produce several specialized metabolites, including alkaloids and volatiles of pharmacological interest. However, there are no reports on how its specialized metabolism (SM) can respond to exogenous application of plant regulators and how it is possible that modulation is associated with primary metabolism (PM). Thus, the objective of this work was to evaluate the SM and PM responses of Annona emarginata as a function of the application of plant growth regulators. For this, young plants were treated with auxin, methyl jasmonate, salicylic acid and abscisic acid at various concentrations. To know the effect of auxin, a second experiment was carried out using auxin and its inhibitor, observing the response at various times after application. The evaluated responses of the SM were the quantification of the total alkaloids, the oxoaporphine liriodenine, the alkaloids profile in roots and the leaf volatiles profile. For PM, the gas exchange and fluorescence variables of chlorophyll a were determined. The use of plant growth regulators in A. emarginata had a negative effect on gas exchange variables, causing a decrease in CO2 assimilation and Rubisco enzyme carboxylation efficiency. The application of 10-6 M auxin and 10-3 M salicylic acid caused an increase in total alkaloids and liriodenine. All regulators altered the composition of leaf volatiles, with auxin, methyl jasmonate and salicylic acid decreasing the relative proportion of monoterpenes, and abscisic acid caused alterations in sesquiterpenes. Thus, it was possible to demonstrate that A. emarginata alters the energy flow between primary and specialized metabolism as a function of the plant growth regulator applied and that the number and proportion of specialized metabolites are also modulated according to the treatment used.
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Palavras-chave
Metabolismo especializado, Metabolismo primário, Hormônios vegetais, Substâncias voláteis, Fotossíntese, Annonaceae, Alkaloids, Phytohormones, Specialized metabolism, Volatile substances