Análisis del metabolismo de la pared celular en bayas de uva de mesa de variedad Thompson Seedless (Vitis vinífera L.) de fenotipo contrastante en firmeza
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2021
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
La producción y exportación de fruta fresca es una de las principales fuentes de
ingresos en Chile, y la uva de mesa (Vítís vinífera L.) es la especie más cultivada y
comercializada . Una vez cosechados, los racimos de uva deben llegar a sus mercados finales,
lo que supone largos periodos de almacenamiento en frío. Por lo tanto, los parámetros de
calidad de los racimos de uva disminuyen y la firmeza de las bayas es uno de los rasgos más
afectados. La firmeza es un parámetro que oscila a lo largo del desarrollo de la baya de uva,
mostrando una menor firmeza en la vendimia que en los estados inmaduros. En el presente
trabajo, se evaluaron bayas de la variedad Thompson Seedless que mostraron una firmeza
contrastaste en etapas de desarrollo y maduración y almacenamiento en frío . Se estudió la
composición y abundancia de la pared celular y, además, se llevó a cabo un análisis
transcriptómico y metabolómico de las bayas de uva . Los resultados revelaron que en cada
etapa de desarrollo y durante el almacenamiento en frío, las bayas del fenotipo firme
presentaron una mayor cantidad de monosacáridos en su pared celular frente al fenotipo
blando. Además, las bayas del fenotipo blando exhibieron una mayor actividad de enzimas
remodeladoras de pared celular, como PME, PG, PL, ¡3-Gal, ¡3-Xil y a-Man, sugiriendo una
mayor degradación que en el fenotipo firme. Los HGs del fenotipo firme presentaron mayor
conformación de dímeros asociados a iones calcio y, por lo tanto, se encontraron menos
degradados. Los datos analíticos sugieren que el RG-I del fenotipo firme contiene
ramificaciones de galactanos y arabinogalactanos más largas o abundantes que las del
fenotipo blando. El fenotipo blando presentó una menor cantidad de monómeros de XG y
sumado a una mayor expresión de XTH sugiere una mayor degradación de estos polímeros
que en el fenotipo firme. Los análisis transcriptómicos indicaron dos procesos
interesantemente diferenciales, el fenotipo firme presentó una mayor tasa de genes asociados
a la biosíntesis de la pared celular, mientras que el fenotipo blando exhibió una mayor tasa
de genes asociados a remodelado y degradación de la pared celular. Finalmente, los análisis
metabolómicos mostraron que existe una acumulación diferencial de azúcares entre los
fenotipos a lo largo del desarrollo, lo que, además, indicó diferencias importantes en el
metabolismo de la galactosa. Estos resultados sugieren un metabolismo diferencial de la
pared celular en los fenotipos firme y blando, apuntando a una sostenida biosíntesis y menor
tasa de degradación de pared celular en el fenotipo firme que podrían estar influyendo en el
parámetro de la firmeza .
The production and exportation of fresh fruit is one of the main sources of income in Chile, and table grapes (Vítís vinífera L.) are the most cultivated and commercialized species. Once harvested, grape bunches must reach their final markets, which involves long periods of cold storage. Therefore, the quality parameters of grape bunches decrease, and berry firmness is one of the most affected traits. Firmness is a para meter that oscillates throughout the development of the grape berry, showing lower firmness at harvest than in the immature stages. In the present work, berries from the variety Thompson Seedless showing contrasting firmness at developmental and ripening stages and cold storage were evaluated. Cell wall composition and abundance were studied and, in addition, transcriptomic and metabolomic analysis of grape berries was carried out. The results revealed that at each stage of development and during cold storage, berries of the hard phenotype had a higher amount of monosaccharides in their cell wall compared to the soft phenotype. In addition, berries of the soft phenotype exhibited higher activity of cell wall remodeling enzymes, such as PME, PG, PL, ~-Gal, ~-Xil and a-Man, suggesting greater degradation than in the hard phenotype. The HGs of the hard phenotype presented increased conformation of dimers associated with calcium ions and, therefore, were found to be less degraded. The analytical data suggest that the RG-I of the hard phenotype contains longer or more abundant galactan and arabinogalactan branches than those of the soft phenotype. The soft phenotype presented a lower amount of XG monomers and with a higher expression of XTH suggests a higher degradation of these polymers than in the hard phenotype. Transcriptomic analyses indicated two interestingly differential processes, the hard phenotype presented a higher rate of genes associated with cell wall biosynthesis, while the soft phenotype exhibited a higher rate of genes associated with cell wall remodeling and degradation. Finally, metabolomic analyses showed that there is a differential accumulation of sugars between phenotypes throughout development, which, in addition, indicated important differences in galactose metabolism. These results suggest differential cell wall metabolism in the hard and soft phenotypes, pointing to a sustained biosynthesis and lower rate of cell wall degradation in the hard phenotype that could be influencing the firmness parameter.
The production and exportation of fresh fruit is one of the main sources of income in Chile, and table grapes (Vítís vinífera L.) are the most cultivated and commercialized species. Once harvested, grape bunches must reach their final markets, which involves long periods of cold storage. Therefore, the quality parameters of grape bunches decrease, and berry firmness is one of the most affected traits. Firmness is a para meter that oscillates throughout the development of the grape berry, showing lower firmness at harvest than in the immature stages. In the present work, berries from the variety Thompson Seedless showing contrasting firmness at developmental and ripening stages and cold storage were evaluated. Cell wall composition and abundance were studied and, in addition, transcriptomic and metabolomic analysis of grape berries was carried out. The results revealed that at each stage of development and during cold storage, berries of the hard phenotype had a higher amount of monosaccharides in their cell wall compared to the soft phenotype. In addition, berries of the soft phenotype exhibited higher activity of cell wall remodeling enzymes, such as PME, PG, PL, ~-Gal, ~-Xil and a-Man, suggesting greater degradation than in the hard phenotype. The HGs of the hard phenotype presented increased conformation of dimers associated with calcium ions and, therefore, were found to be less degraded. The analytical data suggest that the RG-I of the hard phenotype contains longer or more abundant galactan and arabinogalactan branches than those of the soft phenotype. The soft phenotype presented a lower amount of XG monomers and with a higher expression of XTH suggests a higher degradation of these polymers than in the hard phenotype. Transcriptomic analyses indicated two interestingly differential processes, the hard phenotype presented a higher rate of genes associated with cell wall biosynthesis, while the soft phenotype exhibited a higher rate of genes associated with cell wall remodeling and degradation. Finally, metabolomic analyses showed that there is a differential accumulation of sugars between phenotypes throughout development, which, in addition, indicated important differences in galactose metabolism. These results suggest differential cell wall metabolism in the hard and soft phenotypes, pointing to a sustained biosynthesis and lower rate of cell wall degradation in the hard phenotype that could be influencing the firmness parameter.
Notas
Tesis (Doctor en Biotecnología)
Palabras clave
Uva de Mesa, Calidad, Paredes Celulares de las Plantas, Metabolismo, Análisis, Fenotipo