Estudo metabolômico de genótipos de café resistentes ou suscetíveis ao bichomineiro- do-cafeeiro (Leucoptera coffeella)
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Data
2021-09-10
Autores
Correia, Lilian Cherubin [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O café é uma cultura de grande importância econômica no Brasil. No país, o principal problema fitosanitário de cafeeiros é a praga conhecida por bicho-mineiro (Leucoptera coffeella), que gera perdas de produtividade em alta escala. O Programa de Melhoramento Genético em Café do Instituto Agronômico de Campinas (IAC), desenvolveu híbridos entre as espécies Coffea arabica e Coffea racemosa que possuem diferentes níveis de resistência contra o ataque de L. coffeella, porém o mecanismo de resistência nessa interação não foi elucidado. Há quase 20 anos estudos têm sido realizados nesse sentido e nenhuma correlação foi encontrada, porém sabe-se que a antibiose possui papel fundamental nessa resistência. Desvendar o mecanismo de resistência e encontrar os aleloquímicos responsáveis é de suma importância para a seleção precoce de plantas e obtenção de novos cultivares resistentes. Portanto, o objetivo desse trabalho foi utilizar diferentes abordagens metabolômicas para identificação de aleloquímicos que possam mediar a resistência em híbridos considerados resistentes. Plantas resistentes e suscetíveis, atacadas ou não pelo bicho-mineiro foram utilizadas durante o trabalho. Foram avaliados num contexto de metabolômica alvo os ciclotídeos, diterpenos (cafestol, caveol e 16-metil-cafestol), taninos hidrolisáveis ou condensados, ácido ursólico na cera cuticular e nos tecidos foliares internos, além da análise de metabolômica global por cromatografia líquida acoplada à espectrometria de massas (LC-MS) e por cromatografia gasosa acoplada à espectrometria de massas (GC-MS). Foi encontrado que os teores de taninos condensados nas folhas e de ácido ursólico na cera cuticular, possuem diferença estatística durante a infestação do bicho-mineiro. Além disso, verificou-se a presença de um alcaloide piridínico, nunca antes relatado no gênero Coffea, detectado apenas no genótipo resistente e com aumento de teor durante o desenvolvimento da infestação pelas lagartas do bicho-mineiro. Portanto, sugere-se que a antibiose seja relacionada aos taninos condensados, ácido ursólico na cera cuticular e/ou o aleloquímico da classe dos alcaloides.
Coffee is a crop of great economic importance in Brazil. In the country, the major pest is an insect called the coffee leaf-miner (Leucoptera coffeella), popularly known as “bicho-mineiro”, which generates huge losses in the productivity of beans. The Coffee Breeding Program from the Agronomic Institute of Campinas (IAC) developed hybrids between Coffea arabica and Coffea racemosa species that have different levels of resistance against L. coffeella, but the mechanism of resistance in this interaction has not been elucidated. Studies have been carried out in this direction for almost 20 years and no correlation has been found, but it is known that antibiosis plays a fundamental role in the insect-plant resistance. Unraveling the resistance mechanism and finding the responsible allelochemicals is of great importance for the early selection of plants and obtaining new resistant cultivars. Therefore, the objective of this work was to use different metabolomic approaches to identify allelochemicals that can mediate the resistance in hybrids considered resistant. Resistant or susceptible plants, attacked or not by the coffee leaf-miner were used during the work. Cyclotides; diterpenes (cafestol, kaweol and 16-methyl-cafestol); hydrolyzable or condensed tannins; ursolic acid in the cuticular wax or in the internal leaf tissues were evaluated in a context of target metabolomics and liquid chromatography coupled to mass spectrometry (LCMS) and gas chromatography coupled with mass spectrometry (GC-MS) were also used for the untarget metabolomics analysis. It was found that the content of condensed tannins in the leaves and ursolic acid in the cuticular wax, have statistical differences during the insect infestation. Furthermore, the presence of a pyridine alkaloid never reported in the Coffea genus was found only in the resistant genotype and an accumulation of this compound was observed during the coffee leaf-miner infestation. Therefore, it is suggested that antibiosis may be related to the following allelochemicals: condensed tannin, ursolic acid in the cuticular wax and/or the pyridine alkaloid.
Coffee is a crop of great economic importance in Brazil. In the country, the major pest is an insect called the coffee leaf-miner (Leucoptera coffeella), popularly known as “bicho-mineiro”, which generates huge losses in the productivity of beans. The Coffee Breeding Program from the Agronomic Institute of Campinas (IAC) developed hybrids between Coffea arabica and Coffea racemosa species that have different levels of resistance against L. coffeella, but the mechanism of resistance in this interaction has not been elucidated. Studies have been carried out in this direction for almost 20 years and no correlation has been found, but it is known that antibiosis plays a fundamental role in the insect-plant resistance. Unraveling the resistance mechanism and finding the responsible allelochemicals is of great importance for the early selection of plants and obtaining new resistant cultivars. Therefore, the objective of this work was to use different metabolomic approaches to identify allelochemicals that can mediate the resistance in hybrids considered resistant. Resistant or susceptible plants, attacked or not by the coffee leaf-miner were used during the work. Cyclotides; diterpenes (cafestol, kaweol and 16-methyl-cafestol); hydrolyzable or condensed tannins; ursolic acid in the cuticular wax or in the internal leaf tissues were evaluated in a context of target metabolomics and liquid chromatography coupled to mass spectrometry (LCMS) and gas chromatography coupled with mass spectrometry (GC-MS) were also used for the untarget metabolomics analysis. It was found that the content of condensed tannins in the leaves and ursolic acid in the cuticular wax, have statistical differences during the insect infestation. Furthermore, the presence of a pyridine alkaloid never reported in the Coffea genus was found only in the resistant genotype and an accumulation of this compound was observed during the coffee leaf-miner infestation. Therefore, it is suggested that antibiosis may be related to the following allelochemicals: condensed tannin, ursolic acid in the cuticular wax and/or the pyridine alkaloid.
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Palavras-chave
Taninos, Ácido ursólico, Cera cuticular, Resistência, Metabolômica, Aleloquímicos, Alcaloides