Natural variation in expression of genes associated with carotenoid biosynthesis and accumulation in cassava (Manihot esculenta Crantz) storage root.

ABSTRACT: BACKGROUND: Cassava (Manihot esculenta Crantz) storage root provides a staple food source for millions of people worldwide. Increasing the carotenoid content in storage root of cassava could provide improved nutritional and health benefits. Because carotenoid accumulation has been associated with storage root color, this study characterized carotenoid profiles, and abundance of key transcripts associated with carotenoid biosynthesis, from 23 landraces of cassava storage root ranging in color from white-to-yellow-to-pink. This study provides important information to plant breeding programs aimed at improving cassava storage root nutritional quality. RESULTS: Among the 23 landraces, five carotenoid types were detected in storage root with white color, while carotenoid types ranged from 1 to 21 in storage root with pink and yellow color. The majority of storage root in these landraces ranged in color from pale-to-intense yellow. In this color group, total ß-carotene, containing all-E-, 9-Z-, and 13-Z-ß-carotene isomers, was the major carotenoid type detected, varying from 26.13 to 76.72 %. Although no ?-carotene was observed, variable amounts of a ?-ring derived xanthophyll, lutein, was detected; with greater accumulation of ?-ring xanthophylls than of ß-ring xanthophyll. Lycopene was detected in a landrace (Cas51) with pink color storage root, but it was not detected in storage root with yellow color. Based on microarray and qRT-PCR analyses, abundance of transcripts coding for enzymes involved in carotenoid biosynthesis were consistent with carotenoid composition determined by contrasting HPLC-Diode Array profiles from storage root of landraces IAC12, Cas64, and Cas51. Abundance of transcripts encoding for proteins regulating plastid division were also consistent with the observed differences in total ß-carotene accumulation. CONCLUSIONS: Among the 23 cassava landraces with varying storage root color and diverse carotenoid types and profiles, landrace Cas51 (pink color storage root) had low LYCb transcript abundance, whereas landrace Cas64 (intense yellow storage root) had decreased HYb transcript abundance. These results may explain the increased amounts of lycopene and total ß-carotene observed in landraces Cas51 and Cas64, respectively. Overall, total carotenoid content in cassava storage root of color class representatives were associated with spatial patterns of secondary growth, color, and abundance of transcripts linked to plastid division. Finally, a partial carotenoid biosynthesis pathway is proposed.

Qualidade da carne de ovinos puros e cruzados criados no Semiárido Nordestino brasileiro.

Resumo: A procura por carne de qualidade tem proporcionado ao setor de ovinocultura a adoção por técnicas de produção que possam contribuir para disponibilizar ao mercado produtos que atendam as necessidades dos consumidores, que se tornam cada vez mais exigentes quanto à aquisição de produtos que possam trazer benefícios a saúde. Assim, objetivou-se determinar a qualidade da carne de ovinos puros e cruzados criados no semiárido Nordestino. Utilizaram-se 30 cordeiros machos e fêmeas, oriundos dos cruzamentos Morada Nova x Morada Nova, Rabo Largo x Morada Nova e Santa Inês x Morada Nova, alojados em baias e alimentados com dieta a base de capim Canarana, milho farelo de soja e calcário. Os animais foram abatidos com peso médio de 24 kg de peso vivo e as carcaças mantidas em câmara frigorífica a 4?C, por 24 horas. Após esse período, foi seccionado o músculo Longissimus dorsi que foi embalado, identificado e armazenado a 20?C. Foram determinados os atributos físicos de capacidade de retenção de água, perda de peso por cocção e força de cisalhamento; os atributos químicos como umidade, proteína, cinza, lipídios e colesterol; avaliações subjetivas da carcaça como cor, marmoreio, textura da carne, distribuição da gordura, espessura da gordura e área de olho de lombo; os sensoriais de dureza, suculência, sabor, aroma e aceitação global e o perfil de ácidos graxos. O delineamento utilizado foi em esquema fatorial 3x2 (três grupos genéticos e dois sexos) e as médias comparadas pelo teste de Duncan a 5%. Não houve diferença (p>0,05) entre os genótipos para a composição química da carne, exceto para a variável lipídio (p<0,05). Para as características subjetivas da carcaça o genótipo influenciou (p<0,05) nas variáveis cor, marmoreio e textura da carne. O genótipo promoveu efeito (p<0,05) para as características físicas de capacidade de retenção de água e perda de peso por cocção. Os atributos sensoriais não sofreram efeitos (p>0,05) dos genótipos avaliados. Os genótipos influenciaram (p<0,05) as concentrações dos ácidos graxos saturados, monoinsaturados e poli-insaturados assim como, nas relações ?3:?6 e AGM:AGS. O fator sexo influenciou (p<0,05) nas variáveis umidade, força de cisalhamento, dureza, ácidos graxos desejáveis e relação ?3:?6. O cruzamento entre raças nativas mostrou-se com potencial para a produção de carne de qualidade, a raça Morada Nova melhorou os atributos físico-químicos da carne e em seu perfil lipídico e, o fator sexo melhorou o atributo maciez dando destaque a carne das fêmeas. Abstract: The demand for quality meat products has given the sheep industry sector productions techniques that can contribute providing the market with products that supply the needs of consumers require, who are becoming more demanding as the acquisition of differentiated and bring health benefits. The objective was to evaluate the quality of the pure sheep meat and cross bred in the semiarid Northeast of Brazil. It was used 30 male lambs and female, that came from crosses Morada Nova x Morada Nova, Rabo Largo x Morada Nova and Santa Ines x Morada Nova, housed in pens and fed a diet of grass Canarana, corn soybean meal and limestone. The animals were slaughtered at average weight of 24 kg, live weight, and carcasses kept in refrigeration chamber at 4 ° C for 24 hours. After this period the Longissimus dorsi muscle was selected, packaged, labeled and stored at 20˚C. The physical attributes were determined such as water holding capacity, cooking weight loss and shear force; the chemical attributes such as moisture, protein, ash, lipids and cholesterol; Subjective evaluations such as color, marbling, meat texture, fat distribution, fat thickness and loin eye area; the hardness sensory, juiciness, flavor, aroma and global acceptance and fatty acid profile. The design was a 3x2 factorial arrangement (three genetic groups and two genders) and the measures compared by Duncan test at 5%. There was no difference (p> 0.05) between genotypes for the chemical composition of meat, except for the lipid variable (p <0.05). To the subjective characteristics of the carcass, the genotype influenced (p <0.05) in the variables color, marbling and meat texture. The genotype promoted significant effect (p <0.05) for the physical characteristics, water retention capacity and weight loss on cooking. The sensory attributes did not suffer significant effects (p> 0.05) of the evaluated genotypes. The genotypes influenced (p <0.05) in the concentrations of saturated fatty acids, monounsaturated and polyunsaturated as well as in the relations ω3: ω6 and AGM:AGS. The gender factor influenced (P <0.05) in the variables moisture, shear strength, hardness, desirable fatty acids and relation ω3: ω6. The cross between native breeds showed up with potential for quality meat production, the Morada Nova improved the physical and chemical attributes of the flesh and in their lipid profiles and sex factor improved softness attribute highlighting the meat of females.