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Characterization in silico of flavonoids biosynthesis in Theobroma cacao L.  [PDF]
Arsenio Rodriguez,Diogenes Infante
Network Biology , 2011,
Abstract: A detailed and curated map of molecular interactions taking place in the polyphenols (flavonoids) biosynthesis in Theobroma cacao L. is presented. The map was created using the software Cytoscape v.2.7 and the KEGG (Kyoto Encyclopedia of Genes and Genomes) database. The statistical parameters of the network were determined with CentiScape v.1.1 and MetaAnalyzer v.2.6.1. A preliminary theoretical map containing 1024 chemical species and 1099 chemical reactions was built, then a second map that was curated and annotated with the biological facts obtained from approximately 85 publications in T. cacao, with 653 chemical species and 706 chemical reactions. Structural analysis of this interaction network revealed similitude with other biological networks. The study of complex networks opens the way for creating realistic computational models of flavonoid biosynthesis metabolic pathways in cacao.
Sorption characteristics of fermented cocoa powder (Theobroma cacao)
Sandoval,Aleida J; Barreiro,José A; Tovar,Xiomara; Angueira,Mercedes;
Revista Técnica de la Facultad de Ingeniería Universidad del Zulia , 2002,
Abstract: water isotherms of fermented (venezuelan fine first grade) cocoa beans (theobroma cacao) were determined at three temperatures: 5°c, 15°c and 30°c, in ground samples. the data obtained were adjusted to several regression models in order to determine the best fit. differences were not significant among between the determined isotherms, being all data adjusted to a single isotherm in the temperature range used. the halsey equation was suggested for fitting data. this equation is valid for the usual interval of water activity in the product. it could be used another equation that shows a good regression coefficient. an increased sorption enthalpy value was obtained as the temperature raised.
Cocoa Bean (Theobroma cacao L.)Drying Kinetics
MacManus Chinenye,Ndukwu; Ogunlowo,A.S; Olukunle,O.J;
Chilean journal of agricultural research , 2010, DOI: 10.4067/S0718-58392010000400014
Abstract: cocoa (theobroma cacao l.) is widely produced in west africa and south america and is a great economic tree crop, with so many industrial uses. in this work, the experimental drying kinetics of foreign species was investigated, and the experiments were carried out under isothermal conditions, using heated batch drier at 55, 70 and 81 oc. the moisture ratio data obtained from change of moisture content with the drying time was fit to two thin layer drying model with good results. a faster drying process was observed at a higher drying temperature resulting in higher drying rates which is advantageous when evaluating costs. fick?s second law of diffusion was used to predict effective diffusivity using experimental data assuming that the variation of diffusivity with temperature can be expressed by an arrhenius type function, and the values of diffusivity obtained ranged from 6.137 x 10-10 to 2.1855 x 10-9 m2 s-1 for the temperature used. the arrhenius constant (d) is predicted at 8.64 x 10-4 m2 s-1 while the activation energy was predicted at 39.94 kj mol-1.
Somatic embryogenesis and plant regeneration in elite clones of Theobroma cacao
Silva, Thiago édson Ribeiro da;Cidade, Luciana Cardoso;Alvim, Fátima Cerqueira;Cascardo, Júlio Cézar de Mattos;Costa, Marcio Gilberto Cardoso;
Pesquisa Agropecuária Brasileira , 2008, DOI: 10.1590/S0100-204X2008001000024
Abstract: the objective of this work was to evaluated a procedure for somatic embryogenesis and regeneration of cacao (theobroma cacao l.) elite clones. petal explants from cacao clones tsh 565 and tsh 1188 were cultured on pcg and scg-2 media, for calli growth. somatic embryos were formed on the surface of embryogenic calli after transfer to embryo development (ed) medium. clone tsh 565 showed a higher embryogenic potential than tsh 1188. the best combination of carbon source for embryo induction in ed medium was genotype-specific. embryogenic callus formations increased in micropore tape-sealed petri dishes, irrespective of cacao genotype. mature somatic embryos were successfully converted into plantlets.
Geographic and Genetic Population Differentiation of the Amazonian Chocolate Tree (Theobroma cacao L)  [PDF]
Juan C. Motamayor, Philippe Lachenaud, Jay Wallace da Silva e Mota, Rey Loor, David N. Kuhn, J. Steven Brown, Raymond J. Schnell
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003311
Abstract: Numerous collecting expeditions of Theobroma cacao L. germplasm have been undertaken in Latin-America. However, most of this germplasm has not contributed to cacao improvement because its relationship to cultivated selections was poorly understood. Germplasm labeling errors have impeded breeding and confounded the interpretation of diversity analyses. To improve the understanding of the origin, classification, and population differentiation within the species, 1241 accessions covering a large geographic sampling were genotyped with 106 microsatellite markers. After discarding mislabeled samples, 10 genetic clusters, as opposed to the two genetic groups traditionally recognized within T. cacao, were found by applying Bayesian statistics. This leads us to propose a new classification of the cacao germplasm that will enhance its management. The results also provide new insights into the diversification of Amazon species in general, with the pattern of differentiation of the populations studied supporting the palaeoarches hypothesis of species diversification. The origin of the traditional cacao cultivars is also enlightened in this study.
Population densities and genetic diversity of actinomycetes associated to the rhizosphere of Theobroma cacao
Barreto, Tamara R.;Silva, Augusto C.M. da;Soares, Ana Cristina F.;Souza, Jorge T. de;
Brazilian Journal of Microbiology , 2008, DOI: 10.1590/S1517-83822008000300010
Abstract: in spite of the acknowledged importance of growth-promoting bacteria, only a reduced number of studies were conducted with these microorganisms on theobroma cacao. the objectives of this work were to study the population densities and genetic diversity of actinomycetes associated with the rhizosphere of cacao as a first step in their application in plant growth promotion and biological control. the populations densities of actinomycetes in soil and cacao roots were similar, with mean values of 1,0 x 106 cfu/g and 9,6 x 105 cfu/g, respectively. all isolates selected and used in this study were identified through sequencing analyses of a fragment of the rpob gene that encodes the β-subunit of the rna polymerase as species of the genus streptomyces. in vitro cellulolytic, xilanolytic and chitinolytic activity, indolacetic acid production and phosphate solubilization activities were observed in most of the isolates tested. the data obtained in this study demonstrate that actinomycetes account for a higher percentage of the total population of culturable bacteria in soil than on cacao roots. additionally, actinomycetes from the cacao rhizosphere are genetically diverse and have potential applications as agents of growth promotion.
Theobroma cacao L. CLONES MOLECULAR CHARACTERIZATION USING MOLECULAR MICROSATELLITE MARKERS
JULIANA LONDO?O MURILLO,DIANA MARíA GIL VILLA,SANDRA BIBIANA AGUILAR MARíN,FREDY ARVEY RIVERA PáEZ
Luna Azul , 2011,
Abstract: Theobroma cacao L. is the only Theobroma species that is commercially exploited in enormous extensions, registering presently wide distribution worldwide through development programs directly influenced by factors linked to the market and the producers, traders, industrials, and consumers’ interests. In this study 12 cacao clones were evaluated by means of molecular markers using 10 microsatellite sequences (SSRs) as a pilot study before a test at a greater scale. The data were processed using the Power Maker Version 3.25 program. The allelic frequencies were stimated and a genetic distance matrix was developed based on the Nei coefficient. Using the UPGMA grouping algorithm the corresponding dendrogram was generated. The diversity analysis showed a total genetic diversity index of 0.6944 considered intermediate for the materials evaluated. The average heterozygocity estimate was 0.58579 and the average polymorphic information content was 0.6523. In this study markers mTcCIR6, mTcCIR25, mTcCIR26 and mTcCIR12 are the most informative and polymorphic ones. It is recommended to relate the genetic diversity results with morpho-agronomic and pathogenicity characters in the different cacao clones in order to consolidate efficient strategies for disease improvement and control.
Cocoa Bean (Theobroma cacao L.)Drying Kinetics Cinética del Secado de Cocoa (Theobroma cacao L.)  [cached]
Ndukwu MacManus Chinenye,A.S Ogunlowo,O.J Olukunle
Chilean Journal of Agricultural Research , 2010,
Abstract: Cocoa (Theobroma cacao L.) is widely produced in West Africa and South America and is a great economic tree crop, with so many industrial uses. In this work, the experimental drying kinetics of foreign species was investigated, and the experiments were carried out under isothermal conditions, using heated batch drier at 55, 70 and 81 oC. The moisture ratio data obtained from change of moisture content with the drying time was fit to two thin layer drying model with good results. A faster drying process was observed at a higher drying temperature resulting in higher drying rates which is advantageous when evaluating costs. Fick’s second law of diffusion was used to predict effective diffusivity using experimental data assuming that the variation of diffusivity with temperature can be expressed by an Arrhenius type function, and the values of diffusivity obtained ranged from 6.137 x 10-10 to 2.1855 x 10-9 m2 s-1 for the temperature used. The Arrhenius constant (D) is predicted at 8.64 x 10-4 m2 s-1 while the activation energy was predicted at 39.94 kJ mol-1. El cacao (Theobroma cacao L.) es ampliamente producido en el Oeste de áfrica y Sudamérica y es un cultivo de gran importancia económica, con muchos usos industriales. En este trabajo se investigó la cinética del secado experimental de especies foráneas, y se realizaron experimentos bajo condiciones isotérmicas, usando un secador discontinuo en caliente a 55, 70 y 81 °C. Los datos de relación de humedad obtenidos desde el cambio de contenido de humedad con el tiempo de secado se ajustaron a un modelo de secado de dos capas delgadas con buenos resultados. Se observó un proceso de secado más rápido a una temperatura de secado mayor resultando en mayores tasas de secado, lo que es ventajoso al evaluar costos. La segunda ley de difusión de Fick se usó para predecir difusividad efectiva usando datos experimentales, asumiendo que la variación de difusividad con la temperatura puede ser expresada por una función tipo Arrhenius, y los valores de difusividad obtenidos variaron de 6,137 x 10-10 a 2,1855 x 10-9 m2 s-1 para la temperatura usada. La constante de Arrhenius (D) predicha fue 8,64 x 10-4 m2 s-1 mientras la energía de activación predicha fue 39,94 kJ mol-1.
Functional analysis of the Theobroma cacao NPR1 gene in arabidopsis
Zi Shi, Siela N Maximova, Yi Liu, Joseph Verica, Mark J Guiltinan
BMC Plant Biology , 2010, DOI: 10.1186/1471-2229-10-248
Abstract: A putative Theobroma cacao NPR1 cDNA was isolated by RT-PCR using degenerate primers based on homologous sequences from Brassica, Arabidopsis and Carica papaya. The cDNA was used to isolate a genomic clone from Theobroma cacao containing a putative TcNPR1 gene. DNA sequencing revealed the presence of a 4.5 kb coding region containing three introns and encoding a polypeptide of 591 amino acids. The predicted TcNPR1 protein shares 55% identity and 78% similarity to Arabidopsis NPR1, and contains each of the highly conserved functional domains indicative of this class of transcription factors (BTB/POZ and ankyrin repeat protein-protein interaction domains and a nuclear localization sequence (NLS)). To functionally define the TcNPR1 gene, we transferred TcNPR1 into an Arabidopsis npr1 mutant that is highly susceptible to infection by the plant pathogen Pseudomonas syringae pv. tomato DC3000. Driven by the constitutive CaMV35S promoter, the cacao TcNPR1 gene partially complemented the npr1 mutation in transgenic Arabidopsis plants, resulting in 100 fold less bacterial growth in a leaf infection assay. Upon induction with SA, TcNPR1 was shown to translocate into the nucleus of leaf and root cells in a manner identical to Arabidopsis NPR1. Cacao NPR1 was also capable of participating in SA-JA signaling crosstalk, as evidenced by the suppression of JA responsive gene expression in TcNPR1 overexpressing transgenic plants.Our data indicate that the TcNPR1 is a functional ortholog of Arabidopsis NPR1, and is likely to play a major role in defense response in cacao. This fundamental knowledge can contribute to breeding of disease resistant cacao varieties through the application of molecular markers or the use of transgenic strategies.Plants have evolved a complex network of defense responses, often associated with a response local to the site of infection [1-4]. In addition, defenses are also systemically induced in remote parts of the plant in a process known as systemic acqu
Chromatin differentiation between Theobroma cacao L. and T. grandiflorum Schum
Dantas, Liliane G.;Guerra, Marcelo;
Genetics and Molecular Biology , 2010, DOI: 10.1590/S1415-47572009005000103
Abstract: a comparative analysis of mitotic chromosomes of theobroma cacao (cacao) and t. grandiflorum (cupua?u) was performed aiming to identify cytological differences between the two most important species of this genus. both species have symmetric karyotypes, with 2n = 20 metacentric chromosomes ranging in size from 2.00 to 1.19 μm (cacao) and from 2.21 to 1.15 mm (cupua?u). the interphase nuclei of both species were of the arreticulate type, displaying up to 20 chromocentres, which were more regularly shaped in cacao than in cupua?u. prophase chromosomes of both species were more condensed in the proximal region, sometimes including the whole short arm. both species exhibited only one pair of terminal heterochromatic bands, positively stained with chromomycin a3, which co-localized with the single 45s rdna site. each karyotype displayed a single 5s rdna site in the proximal region of another chromosome pair. heterochromatic bands were also observed on the centromeric/pericentromeric regions of all 20 chromosomes of cacao after c-banding followed by giemsa or dapi staining, whereas in cupua?u they were never detected. these data suggest that the chromosomes of both species have been largely conserved and their pericentromeric chromatin is the only citologically differentiated region.
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