RESUMO
Smallanthus sonchifolius, also known as yacón, is an Andean crop species commercialized for its nutraceutical and medicinal properties. The tuberous roots of yacón accumulate a diverse array of probiotic and bioactive metabolites including fructooligosaccharides and caffeic acid esters. However, the metabolic diversity of yacón remains unexplored, including the site of biosynthesis and accumulation of key metabolite classes. We report herein a multidisciplinary approach involving metabolomics, gene expression and scanning electron microscopy, to provide a comprehensive analysis of the diversity, distribution and spatial regulation of the specialized metabolism in yacón. Our results demonstrate that different metabolic fingerprints and gene expression patterns characterize specific tissues, organs and cultivars of yacón. Manual inspection of mass spectrometry data and molecular networking allowed the tentative identification of 71 metabolites, including undescribed structural analogues of known bioactive compounds. Imaging by scanning electron microscopy revealed the presence of a new type of glandular trichome in yacón bracts, with a distinctive metabolite profile. Furthermore, the high concentration of sesquiterpene lactones in capitate glandular trichomes and the restricted presence of certain flavonoids and caffeic acid esters in underground organs and internal tissues suggests that these metabolites could be involved in protective and ecological functions. This study demonstrates that individual organs and tissues make specific contributions to the highly diverse and specialized metabolome of yacón, which is proving to be a reservoir of previously undescribed molecules of potential significance in human health.
Assuntos
Asteraceae/metabolismo , Suplementos Nutricionais/análise , Regulação da Expressão Gênica de Plantas , Metaboloma , Compostos Fitoquímicos/metabolismo , Extratos Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Asteraceae/genética , Asteraceae/crescimento & desenvolvimento , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismoRESUMO
Acting as chemical defense or signaling compounds, secondary metabolites (SMs) play an essential role in the evolutionary success of many angiosperm plant families. However, the adaptive advantages that SMs confer, and the influence of environmental and developmental factors on SMs expression, remains poorly understood. A study of taxa endemic to the variable Andean climate, using a metabolomics approach, may provide further insight. By analyzing gene expression patterns and metabolic fingerprints, we report herein the developmental and environmental regulation of the secondary metabolism of Smallanthus sonchifolius (yacón), a medicinal Andean plant. Our results demonstrate a clear developmental stage dependent regulation of the secondary metabolism of yacón leaves wherein the metabolic diversity increases with plant age. However, environmental factors seem to regulate biosynthetic pathways, creating differences in the expression of chemical classes, pointing to an association between transcription levels of relevant genes and the relative amounts of more than 40 different metabolites. This study suggests that the secondary metabolism of yacón is regulated by a complex interplay between environmental factors and developmental stage and provides insight into the regulatory factors and adaptive roles of SMs in Andean taxa.
Assuntos
Asteraceae/genética , Asteraceae/metabolismo , Meio Ambiente , Perfilação da Expressão Gênica/métodos , Metabolômica/métodos , Metabolismo Secundário/genética , Asteraceae/crescimento & desenvolvimento , Clima , Análise por Conglomerados , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Umidade , Luz , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Chuva , TemperaturaRESUMO
La producción de metabolitos secundarios en cultivos celulares de plantas puede ser de interés para obtener compuestos difíciles de sintetizar o aislar de otras fuentes, lo cual generalmente se relaciona con un alto valor económico, aunque también puede ser útil para ayudar a dilucidar las vías metabólicas involucradas en la síntesis de estos compuestos. En este trabajo se presenta una descripción general de las antocianinas, un grupo de pigmentos de gran importancia para la industria, complementada con la referencia de los trabajos científicos recientes que se han publicado sobre la producción in vitro de las mismas. Con relación a esto último, se hace una descripción del efecto de cambios en las condiciones de cultivo, de la adición de precursores, del uso de reguladores de crecimiento, así como de la utilización de inductores y factores de estrés sobre la producción de estos compuestos. Finalmente, se hace mención al uso de raíces en cabellera, en inglés hairy roots, obtenidas mediante el uso de Agrobacterium rhizogenes, para la producción de estos compuestos.
The production of secondary metabolites in plant cell cultures may be of interest for obtaining compounds that are difficult to synthesize or isolate from other sources, which is usually associated with high economic value of the substances, but may also be useful to help elucidating the metabolic pathways involved in the synthesis of such compounds. This paper presents a general description of anthocyanins, a group of pigments of great importance to the industry, complemented by referring the scientific papers that have been recently published on their in vitro production. Regarding the latter, a description of the effect of changes in growing conditions, of the addition of precursors, of the use of growth regulators, and of the utilization of elicitors and stressors on the production of these compounds, is done. Finally, this review mentions the use of hairy roots obtained by the use of Agrobacterium rhizogenes for the production of these compounds.