9 research outputs found
De novo transcriptome sequencing in Bixa orellana to identify genes involved in methylerythritol phosphate, carotenoid and bixin biosynthesis.
BackgroundBixin or annatto is a commercially important natural orange-red pigment derived from lycopene that is produced and stored in seeds of Bixa orellana L. An enzymatic pathway for bixin biosynthesis was inferred from homology of putative proteins encoded by differentially expressed seed cDNAs. Some activities were later validated in a heterologous system. Nevertheless, much of the pathway remains to be clarified. For example, it is essential to identify the methylerythritol phosphate (MEP) and carotenoid pathways genes.ResultsIn order to investigate the MEP, carotenoid, and bixin pathways genes, total RNA from young leaves and two different developmental stages of seeds from B. orellana were used for the construction of indexed mRNA libraries, sequenced on the Illumina HiSeq 2500 platform and assembled de novo using Velvet, CLC Genomics Workbench and CAP3 software. A total of 52,549 contigs were obtained with average length of 1,924 bp. Two phylogenetic analyses of inferred proteins, in one case encoded by thirteen general, single-copy cDNAs, in the other from carotenoid and MEP cDNAs, indicated that B. orellana is closely related to sister Malvales species cacao and cotton. Using homology, we identified 7 and 14 core gene products from the MEP and carotenoid pathways, respectively. Surprisingly, previously defined bixin pathway cDNAs were not present in our transcriptome. Here we propose a new set of gene products involved in bixin pathway.ConclusionThe identification and qRT-PCR quantification of cDNAs involved in annatto production suggest a hypothetical model for bixin biosynthesis that involve coordinated activation of some MEP, carotenoid and bixin pathway genes. These findings provide a better understanding of the mechanisms regulating these pathways and will facilitate the genetic improvement of B. orellana
Carotenoid Derivates in Achiote (Bixa orellana) Seeds: Synthesis and Health Promoting Properties
Bixa orellana (family Bixaceae) is a neotropical fast growing perennial tree of great agro-industrial value because its seeds have a high carotenoid content, mainly bixin. It has been used since pre-colonial times as a culinary colorant and spice, and for healing purposes. It is currently used as a natural pigment in the food, in pharmaceutical, and cosmetic industries, and it is commercially known as annatto. Recently, several studies have addressed the biological and medical properties of this natural pigment, both as potential source of new drugs or because its ingestion as a condiment or diet supplement may protect against several diseases. The most documented properties are anti-oxidative; but its anti-cancer, hypoglucemic, antibiotic and anti-inflammatory properties are also being studied. Bixin’s pathway elucidation and its regulation mechanisms are critical to improve the produce of this important carotenoid. Even though the bixin pathway has been established, the regulation of the genes involved in bixin production remains largely unknown. Our laboratory recently published B. orellana’s transcriptome and we have identified most of its MEP (methyl-D-erythritol 4-phosphate) and carotenoid pathway genes. Annatto is a potential source of new drugs and can be a valuable nutraceutical supplement. However, its nutritional and healing properties require further study
Reconstrucción de la evolución genómica de los begomovirus por medio de un enfoque multidisciplinario integrado
"Los geminivirus son patógenos de plantas superiores caracterizados por una cápside geminada y un genoma compuesto por una o dos moléculas circulares de ADN de cadena sencilla (ADNcs). El género Begomovirus, con más de 200 especies, es el subgrupo de la familia Geminiviridae más diverso y de distribución mundial más amplia. Este género incluye a los únicos geminivirus que poseen genomas compuestos por dos moléculas de ADNcs. El ADN-A codifica proteínas necesarias para la replicación viral, el control de la expresión de genes tardíos, la formación de la cápside y la supresión de respuestas antivirales del huésped. El DNA-B, por otra parte, codifica dos proteínas, BV1 y BC1, que están involucradas en el movimiento intracelular e intercelular del virus. Diversas líneas de evidencia sugieren que los begomovirus (BGVs) evolucionaron hace 130-110 millones de años, pero quedan por resolver todavía varias cuestiones fundamentales de su historia evolutiva, incluyendo la ubicación de su centro de origen, su migración al continente americano, y la importante y controversial cuestión relativa al origen del segundo componente genómico. Mediante el empleo de una amplia gama de programas para la inferencia de filogenias a partir de las secuencias de ADN y proteínas, el análisis filogenético-estructural de secuencias no-codificantes, la identificación de marcadores moleculares biogeográficos, la información proporcionada por los fósiles virales, y los datos paleobiogeográficos del vector, logramos establecer que el centro de origen de los BGVs se localiza en la India. El análisis condujo también a la conclusión de que los BGVs de América se derivaron de BGVs originarios del subcontinente Indio, y postulamos la hipótesis de que uno o más linajes de la India arribaron a Sudamérica en la Era Cenozoica, a través del continente Antártico. Finalmente, utilizando diversos métodos para reconstruir secuencias ancestrales y trazar homologías remotas, logramos establecer que el ADN-B se derivó evolutivamente de un ADN-A ancestral, a través de un proceso que involucró divergencia y especialización génica en el caso del gen BV1, y la generación por un mecanismo de “sobre-inscripción” (“overprinting”) de un nuevo gen, BC1, a partir de tres genes ancestrales (AC1, AC2 y AC3) con funciones no relacionadas al movimiento viral. Este último proceso representa un caso inédito de evolución molecular, la emergencia de un gen con una nueva función a partir de las secuencias de tres genes""Geminiviruses are important plant pathogens characterized by a geminate capsid and a genome composed by one or two circular molecules of single-stranded DNA (ssDNA). The genus Begomovirus, with over 200 species, is the subgroup of the family Geminiviridae that is more diversified and widely distributed in the world. Begomoviruses are the only geminiviruses possessing genomes composed by two DNAs molecules (DNA-A and DNA-B). The DNA-A encodes proteins necessary for virus replication, control of gene expression, suppression of gene silencing, and encapsidation. The DNAB, on the other hand, encodes two proteins, BV1 and BC1, which are involved in the intracellular and intercellular movement of the virus. Several lines of evidence suggest that begomoviruses (BGVs) evolved 130-110 million years ago, but still remain to be resolved several key issues of their evolutionary history, including the location of its center of origin, its migration to the Americas, and the enigmatic issue of the second genomic component evolutionary origin. Employing a wide range of bioinformatics software for inferring phylogenies from DNA and proteins sequences, the phylogeneticstructural analysis of non-coding sequences, the identification of biogeographic molecular markers, the information from viral fossils and the paleobiogeographic data on the whitefly vector, we concluded that the BGVs center of origin is located in India. The analysis also led to the conclusion that American BGVs were derived from Indian subcontinent BGVs, and we postulate the hypothesis that one or more lineages of BGVs arrived to South America in the Cenozoic through the Antarctic continent. Finally, using various methods for reconstructing ancestral sequences and trace remote homologies between genes, we established that DNA-B was derived from an evolutionarily ancient DNA-A, through a process involving gene divergence and specialization in the case of the BV1 gene, and generation of a new gene, BC1, by overprinting from three ancestral genes (AC1, AC2 and AC3) with functions unrelated to viral movement. This latter process represents an unprecedented case of molecular evolution, ie, the emergence of a gene with a new function from the sequences of three overlapping genes with different functions.
L'Alerte : journal indépendant : politique, littéraire et commercial
18 mai 19081908/05/18 (A12)-1908/05/18
Functional polymorphism in lycopene beta-cyclase gene as a molecular marker to predict bixin production in Bixa orellana L. (achiote)
Bixin is an apocarotenoid obtained from the seed aril of Bixa orellana L., a tropical plant known as achiote in Mexico. This compound is the second most commonly used natural colouring for food and pharmaceutical industries. B. orellana is an outcrossing species that displays high genetic variability. Recently, the colour traits of sexual organs were associated with the biosynthesis and accumulation of bixin in mature seeds. Herein, we describe a new approach for genotype–phenotype association by surveying lycopene beta-cyclase (Boβ-LCY1) gene variation in sixteen achiote accessions divided into three groups according to contrasting traits, such as flower colour, fruit colour and bixin production. Using a combination of single-strand conformational polymorphism techniques and the sequencing of polymorphic bands, we identified several single-nucleotide polymorphisms that divided the accessions into three haplotypes. Surprisingly, we observed that these three haplotypes were consistent with the same three groups previously characterized by phenotypic traits. We derived a putative sequence for the Boβ-LCY1 gene and surveyed the variations in this sequence. The heterozygosity of Boβ-LCY1 alleles resulted in a higher bixin content, likely associated with heterosis for this metabolite. These findings augment the toolbox available for the selection and genetic improvement of B. orellana and provide a reliable phenotype–genotype association method for commercial varietal selection, contributing to the development of laboratory techniques to identify desirable traits of commercial plant species
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Gene expression profile during seed development of Bixa orellana accessions varying in bixin pigment
Diverse morphological, cellular and physiological changes occur during seed maturation in Bixa orellana when the seed tissues form specialized cell glands that produce reddish latex with high bixin amounts. Transcriptomic profiling during seed development in three B. orellana accessions (P12, N4 and N5) with contrasting morphologic characteristics showed enrichment in pathways of triterpenes, sesquiterpenes, and cuticular wax biosynthesis. WGCNA allows groups of all identified genes in six modules the module turquoise, the largest and highly correlated with the bixin content. The high number of genes in this module suggests a diversification of regulatory mechanisms for bixin accumulation with the genes belonging to isoprene, triterpenes and carotene pathways, being more highly correlated with the bixin content. Analysis of key genes of the mevalonate (MVA) and the 2C-methyl-D-erythritol-4-phosphate (MEP) pathways revealed specific activities of orthologs of BoHMGR, BoFFP, BoDXS, and BoHDR. This suggests that isoprenoid production is necessary for compounds included in the reddish latex of developing seeds. The carotenoid-related genes BoPSY2, BoPDS1 and BoZDS displayed a high correlation with bixin production, consistent with the requirement for carotene precursors for apocarotenoid biosynthesis. The BoCCD gene member (BoCCD4-4) and some BoALDH (ALDH2B7.2 and ALDH3I1) and BoMET (BoSABATH1 and BoSABATH8) gene members were highly correlated to bixin in the final seed development stage. This suggested a contributing role for several genes in apocarotenoid production. The results revealed high genetic complexity in the biosynthesis of reddish latex and bixin in specialized seed cell glands in different accessions of B. orellana suggesting gene expression coordination between both metabolite biosynthesis processes
Carotenoides en agroalimentación y salud
Los carotenoides son compuestos especiales; si bien es común referirse a ellos como
pigmentos, lo cierto es que son compuestos de gran versatilidad e importancia en la
naturaleza. Más específicamente, son de gran interés en agroalimentación y salud.
Así, por ejemplo, son pigmentos naturales y por lo tanto tienen un importante papel en
la elección de alimentos por parte de los consumidores. Asimismo, algunos de ellos
son precursores de la vitamina A. Sin embargo, que cada vez exista más interés en los
carotenoides en este contexto se debe en gran parte a muchos estudios de distinta
naturaleza que indican que pueden proporcionar beneficios para la salud. Su interés
en alimentación funcional es por lo tanto indudable.
En este libro se refleja la experiencia en carotenoides de un gran número de
profesionales de la región iberoamericana. En conjunto, se ofrece una visión general
de la investigación sobre estos compuestos en agroalimentación y salud. Los autores
son miembros de la red ibercarot (http://carotenoides.us.es), que tiene entre sus
objetivos conformar una red estable y funcional de profesionales que aúnen esfuerzos
en pos de identificar nuevas fuentes de carotenoides de interés nutricional, mejorar su
producción y aumentar el valor de los productos que los contengan.
Me gustaría agradecer a todas y cada una de las personas que han contribuido de
una u otra forma a que este libro sea una realidad. Todos esperamos que sea de
ayuda para personas interesadas en los temas desarrollados. Gracias especialmente
al Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (Cyted, http://
www.cyted.org/) que, con su apoyo económico a la red ibercarot, ha hecho posible
que varias decenas de equipos interaccionen en torno a temas de interés común para
contribuir al desarrollo a distintos niveles de la región iberoamericana.RED TEMÁTICA IBERCAROT (referencia 112RT445) http://carotenoides.us.es
PROGRAMA IBEROAMERICANO DE CIENCIA Y TECNOLOGIA PARA EL DESARROLLO – CYTEDPeer reviewe