Efeito de dose letal e subletal do herbicida glifosato no transcriptoma de abelhas Apis mellifera africanizadas na fase de campeiras
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Data
2022-06-27
Autores
Scheffer, Jaine da Luz
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Universidade Estadual Paulista (Unesp)
Resumo
As abelhas são consideradas eficientes agentes polinizadores, e devido a sua característica generalista na busca de recursos alimentares disponibilizados pelas plantas, ficam sujeitas a situações desfavoráveis encontradas no ambiente, como os agrotóxicos. Dentre eles, o herbicida glifosato tem seu uso autorizado na maioria das culturas, sendo o mais comercializado nacionalmente. Diante disso, objetivou-se com o presente estudo, avaliar a toxicidade do glifosato a partir de alterações no perfil de expressão gênica de abelhas Apis mellifera africanizadas campeiras por meio de teste de ingestão. Para isso, abelhas recém-emergidas de nove colônias foram marcadas na região do pronoto e devolvidas às suas respectivas colônias; após 21 dias, 180 abelhas no total foram coletadas das colônias experimentais. Para os testes de ingestão, estas abelhas foram acondicionadas em placas Petri perfuradas, onde se mantiveram em jejum por 3 horas, totalizando seis repetições com cinco abelhas cada, sendo fornecido então o xarope de mel contendo ou não a dose letal (273,93 µg/abelha) e subletal do glifosato (2,73 µg/abelha). Após 1 e 4 horas de exposição, 15 abelhas foram coletadas aleatoriamente para as análises do transcriptoma do tecido cerebral. O RNA total de cada tratamento foi extraído pelo método de Trizol. Os genes diferencialmente expressos (DEGs) que apresentaram significância estatística foram considerados quando p-valor ajustado para múltiplas comparações < 0,05 e |log 2 FC| ≥ 2. Após a exposição das abelhas ao alimento contendo glifosato, 691 genes foram diferencialmente expressos após uma hora, sendo 404 genes para a dose letal e 538 genes para a dose subletal, com 251 genes expressos em comum para ambas as doses do herbicida. Após quatro horas de exposição das abelhas, foram diferencialmente expressos 499 genes para a dose letal e 483 genes para a dose subletal, totalizando 784 genes diferencialmente expressos, sendo 198 genes expressos para ambas as doses. Observou-se que, independente da dose utilizada, o herbicida glifosato promoveu alterações na expressão de genes relacionados a importantes vias do sistema nervoso das abelhas na fase de campeiras após uma hora de exposição. Após quatro horas de exposição, observou-se mudanças na expressão de genes relacionados a processos metabólicos e também a organelas intracelulares. Pode-se concluir que o herbicida glifosato afeta a expressão gênica de abelhas campeiras expostas de forma aguda, podendo interferir na sua microbiota intestinal, imunidade, sistema cognitivo e, consequentemente, no desenvolvimento da colônia.
Bees are considered efficient pollinating agents, and due to their generalist characteristic in the search for food resources made available by plants, they are subject to unfavorable situations found in the environment, such as pesticides. Among them, the herbicide glyphosate has its use authorized in most crops, being the most commercialized nationally. Therefore, the objective of the present study was to evaluate the toxicity of glyphosate from changes in the gene expression profile of Africanized field bees Apis mellifera by means of an ingestion test. For that purpose, newly emerged bees from nine colonies were marked in the pronotum region and returned to their respective colonies; after 21 days, a total of 180 bees were collected from the experimental colonies. For the ingestion tests, these bees were placed in perforated Petri dishes, where they were maintained fasting for 3 hours, totaling six repetitions with five bees each, and then the honey syrup was supplied with or without the lethal dose (273, 93 µg/bee) and sublethal glyphosate (2,73 µg/bee). After 1 and 4 hours of exposure, 15 bees were randomly collected for brain tissue transcriptome analysis. Total RNA from each treatment was extracted by the Trizol method. The differentially expressed genes (DEGs) that showed statistical significance were considered when p-value adjusted for multiple comparisons < 0,05 and |log 2 FC| ≥ 2. After exposure of the bees to the food containing glyphosate, 691 genes were differentially expressed after one hour, 404 genes for the lethal dose and 538 genes for the sublethal dose, with 251 genes expressed in common for both doses of the herbicide. After four hours of exposure of the bees, 499 genes were differentially expressed for the lethal dose and 483 genes for the sublethal dose, totaling 784 differentially expressed genes, with 198 genes expressed for both doses. It was observed that, regardless of the dose used, the herbicide glyphosate promoted changes in the expression of genes related to important pathways in the nervous system of bees in the forager stage after one hour of exposure. After four hours of exposure, changes were observed in the expression of genes related to metabolic processes and also to intracellular organelles. It can be concluded that the herbicide glyphosate affects the gene expression of acutely exposed forager bees, which may interfere with their intestinal microbiota, immunity, cognitive system and, consequently, the development of the colony.
Bees are considered efficient pollinating agents, and due to their generalist characteristic in the search for food resources made available by plants, they are subject to unfavorable situations found in the environment, such as pesticides. Among them, the herbicide glyphosate has its use authorized in most crops, being the most commercialized nationally. Therefore, the objective of the present study was to evaluate the toxicity of glyphosate from changes in the gene expression profile of Africanized field bees Apis mellifera by means of an ingestion test. For that purpose, newly emerged bees from nine colonies were marked in the pronotum region and returned to their respective colonies; after 21 days, a total of 180 bees were collected from the experimental colonies. For the ingestion tests, these bees were placed in perforated Petri dishes, where they were maintained fasting for 3 hours, totaling six repetitions with five bees each, and then the honey syrup was supplied with or without the lethal dose (273, 93 µg/bee) and sublethal glyphosate (2,73 µg/bee). After 1 and 4 hours of exposure, 15 bees were randomly collected for brain tissue transcriptome analysis. Total RNA from each treatment was extracted by the Trizol method. The differentially expressed genes (DEGs) that showed statistical significance were considered when p-value adjusted for multiple comparisons < 0,05 and |log 2 FC| ≥ 2. After exposure of the bees to the food containing glyphosate, 691 genes were differentially expressed after one hour, 404 genes for the lethal dose and 538 genes for the sublethal dose, with 251 genes expressed in common for both doses of the herbicide. After four hours of exposure of the bees, 499 genes were differentially expressed for the lethal dose and 483 genes for the sublethal dose, totaling 784 differentially expressed genes, with 198 genes expressed for both doses. It was observed that, regardless of the dose used, the herbicide glyphosate promoted changes in the expression of genes related to important pathways in the nervous system of bees in the forager stage after one hour of exposure. After four hours of exposure, changes were observed in the expression of genes related to metabolic processes and also to intracellular organelles. It can be concluded that the herbicide glyphosate affects the gene expression of acutely exposed forager bees, which may interfere with their intestinal microbiota, immunity, cognitive system and, consequently, the development of the colony.
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Palavras-chave
Agrotóxicos, Apicultura, Expressão gênica, Herbicidas, Pesticide, Beekeeping, Gene expression, Herbicide, Agroquímicos, Criação de abelhas