Chemical, metabolomic and proteomic analysis of young cladodes from Opuntia cultivars with different domestication grade

"Nutraceutical potential of Opuntia cladodes has been reported, therapeutical effects have been associated to antioxidant compounds reported in Opuntia, such phenolic acids and flavonoids. Opuntia species have been classified according to their domestication grade. This gradient started with wild and less domesticated O. streptacantha Lem., followed by O. hyptiacantha F.A.C. Weber, then the moderate domesticated O. megacantha Salm-Dyck, prior to O. albicarpa, to finish with O. ficus-indica, the most domesticated and humanized species. The aim of this work was to evaluate the effect of domestication grade on chemical and nutritional attributes, metabolomic profiles and proteomic analysis of taxonomically identified Opuntia species. Proximate composition, mineral content and chemical attributes were different between Opuntia species. However, no clear trend was observed among domestication grade and attribute. Total phenolic and total flavonoids content as well as antioxidant capacity were different among cultivars from collect 2010 and collect 2012. However, the content of total phenolics and antioxidant capacities increased cladodes from collect 2012. These differences were no related to domestication grade. The metabolomic analysis of Opuntia cladodes showed similar profiles. However some compounds were present in specific cultivars. Particularly compound 26’ identified as Kaempferol 3-O-arabinofuranoside was detected only in O. streptacantha, a wild species. Similar 1D patterns were observed in proteomic analysis between cultivars. So far, shotgun analysis allowed the identification of 266 proteins from O. megacantha “Rubí reina” and O. ficusindica “Rojo vigor”, 38 and 61 specific proteins for each cultivar, respectively. Data from O. streptacantha, O. hyptiacantha and O. ficus-indica is still being analyzed. Shotgun analysis showed differences in protein expression due to domestication process. This is the first study of domestication effect on nutritional composition, chemical attributes, phenolic compounds profiling and proteomic analysis by shotgun proteomic in Opuntia cladodes.""En este trabajo se analizaron las especies de Opuntia incluidas en un gradiente de domesticación que inició con O. streptacantha Lem. la especie más primitiva y menos domesticada, seguida de O. hyptiacantha FAC Weber, O. megacantha Salm- Dyck, moderadamente domesticada, luego O. albicarpa, y en el extremo más domesticado y humanizado se encuentra O. ficus-indica. Los efectos terapéuticos se han asociado a los compuestos antioxidantes reportados en Opuntia, tales como ácidos fenólicos y flavonoides. El objetivo de este trabajo fue evaluar el efecto del grado de domesticación en los atributos químicos y nutricionales, perfil metabolómico y proteómico de especies de Opuntia taxonómicamente identificados. La composición proximal, los atributos químicos y contenido de minerales fueron diferentes entre las variedades de Opuntia, aunque no se observó una tendencia en relación al grado de domesticación. Los contenidos de fenoles y flavonoides totales, así como la capacidad antioxidante se modificaron entre las variedades de las colectas 2010 y 2012. Sin embargo, se observó un incremento en el contenido de fenoles totales y capacidad antioxidante en las variedades 2012. Tales diferencias no están relacionadas al grado de domesticación. El análisis de metabolitos mostró perfiles de compuestos fenólicos similares, aunque el análisis diferencial demostró la presencia de compuestos específicos, como el 26’ (kaempferol 3 - O- arabinofuranósido) detectado únicamente en O. streptacantha, la especie más silvestre. El análisis proteómico reveló patrones similares, en primera dimensión, entre variedades. El análisis tipo ”shotgun” permitió la identificación de 266 proteínas en O. megacantha "Rubí reina " y O. ficus -indica "vigor Rojo", así como 38 y 61 proteínas específicas de cada variedad, respectivamente. Los datos obtenidos de O. streptacantha, O. hyptiacantha y O. ficus –indica aún están siendo analizados. El análisis tipo shotgun reveló diferencias relacionadas con el proceso de domesticación de Opuntia. Éste es el primer trabajo sobre el efecto de domesticación en el contenido nutricional, atributos químicos, perfil de compuestos fenólicos y análisis proteómico tipo “shotgun” en cladodios de Opuntia.

Establishment of callus from Opuntia robusta Wendl., a wild and medicinal cactus, for phenolic compounds production

In this work, a protocol for the establishment of callus cultures from Opuntia robusta, a wild and medicinal cactus, was developed. The effects of plant growth regulators and culture media composition on callus development were evaluated.The best response was observed on Murashige and Skoog medium added with 2,4-dichlorophenoxyacetic acid, benzyladenine, biotin, casein hydrolysate and proline. The exposure of O. robusta callus to jasmonic acid increased 1.3-fold and 3-fold total phenolic acids and flavonoids concentration, respectively. The in vitro culture from O. robusta could be a new approach for the obtainment of metabolites with pharmaceutical and/or nutraceutical value.Keywords: Callus, flavonoids, jasmonic acid, wild Opuntia, phenolsAfrican Journal of Biotechnology Vol. 12(21), pp. 3204-320

Comparative shotgun proteomic analysis of wild and domesticated Opuntia spp. species shows a metabolic adaptation through domestication

"The Opuntia genus is widely distributed in America, but the highest richness of wild species are found in Mexico, as well as the most domesticated Opuntia ficus-indica, which is the most domesticated species and an important crop in agricultural economies of arid and semiarid areas worldwide. During domestication process, the Opuntia morphological characteristics were favored, such as less and smaller spines in cladodes and less seeds in fruits, but changes at molecular level are almost unknown. To obtain more insights about the Opuntia molecular changes through domestication, a shotgun proteomic analysis and database-dependent searches by homology was carried out. > 1000 protein species were identified and by using a label-free quantitation method, the Opuntia proteomes were compared in order to identify differentially accumulated proteins among wild and domesticated species. Most of the changes were observed in glucose, secondary, and 1C metabolism, which correlate with the observed protein, fiber and phenolic compounds accumulation in Opuntia cladodes. Regulatory proteins, ribosomal proteins, and proteins related with response to stress were also observed in differential accumulation. These results provide new valuable data that will help to the understanding of the molecular changes of Opuntia species through domestication. Biological significance Opuntia species are well adapted to dry and warm conditions in arid and semiarid regions worldwide, and they are highly productive plants showing considerable promises as an alternative food source. However, there is a gap regarding Opuntia molecular mechanisms that enable them to grow in extreme environmental conditions and how the domestication processes has changed them. In the present study, a shotgun analysis was carried out to characterize the proteomes of five Opuntia species selected by its domestication degree. Our results will help to a better understanding of proteomic features underlying the selection and specialization under evolution and domestication of Opuntia and will provide a platform for basic biology research and gene discovery.