Biosíntesis de ácido tartárico durante el desarrollo de uva de mesa (Vitis vinifera): Cv Thompson Seedless y Red Globe
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Fecha
2012
Autores
Profesor/a Guía
Facultad/escuela
Idioma
es
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Editor
Universidad Andrés Bello
Nombre de Curso
Licencia CC
Licencia CC
Resumen
La uva de mesa (Vitis vinifera) es el principal producto frutícola de exportación de nuestro
país. El carácter organoléptico de la uva está directamente influenciado por las condiciones
climatológicas, así como por el fondo genético propio de cada variedad, el cual se asocia
especialmente a la relación de sólidos solubles/acidez. Entre los ácidos orgánicos de impo11ancia,
encontramos el ácido tartárico, el cual sería un contribuyente relevante en el sabor y por
consecuencia, variaciones en su concentración podría afectar la palatabilidad percibida por el
consumidor. En este trabajo, se planteó la hipótesis que la síntesis de ácido tartárico estaría regulada
diferencialmente por el gen que codifica para la enzima L-Idonato Deshidrogenasa en etapas
tempranas de desarrollo para distintas variedades de vid . Con este propósito, se cuantificaron los
ácidos orgánicos sintetizados y se analizó la expresión del gen de L-Idonato Deshidrogenasa (VvLJdnDH)
durante el desarrollo de dos variedades comerciales de uva de mesa bajo distintas
condiciones geográficas y tratamientos de etileno.
Entre los huertos comerciales (Los Andes y Quinta de Tilcoco) y semi-comercial (Santiago)
ubicados en las distintas regiones de estudio, se observaron diferencias tanto en el contenido de los
ácidos como en la expresión de L-ldnDH. Se observó un aumento en el contenido de ácidos
orgánicos, tanto tm1árico como málico, desde los primeros estadías hasta la etapa de pinta, para luego
descender hasta un nivel basal. Estos resultados podrían estar indicando un posible efecto de la
temperatura sobre algunos rasgos fisiológicos, como fue el tamaño de baya y así afectar la síntesis de
ácido tartárico. Complementariamente, se determinó la posible participación de la hormona etileno
durante el proceso de maduración de la uva de mesa. Se observó una menor acidez, como un menor
contenido de ácidos orgánicos, en aquellas uvas tratadas con etileno exógeno comparado a aquellas
tratadas con un inhibidor de su percepción (1-MCP) y plantas sin aplicación. A nivel génico, no se
observaron diferencias significativas entre tratamientos durante todos los estadías de estudio.
En conclusión, se podría establecer que factores medioambientales y rasgos propios de la uva
de mesa, incluyendo la influencia de etileno en el proceso de maduración, estarían modificando la
síntesis y el contenido de ácido tartárico.
The table grape (Vitis vinífera) is the main fruit of the chilean export fruit market. The organoleptic property is directly influenced by c limatological conditions as well as the genetic background of each cultivar. This feature is associated with soluble so lids/acidity ratio. Tartaric acid is the main organic acid in grapes being one of the major contributor to flavor and therefore, variations in concentration it could affect the palatability perceived by the consumer. In this work, was established the hypothesis established was that tartaric acid synthesis is differentially regulated by the gene encoding L-Idonate Dehydrogenase enzyme in early development stages for different grape varieties. To this purpose, synthesized organic acids and L-Idonate Dehydrogenase gene expression (VvL-ldnDH) were quantified during the development of two commercial varieties of table grapes, in different geographical conditions and ethylene treatments. Rapes from orchards located in different regions, commercial (Los Andes and Quinta de Tilcoco) and semi-commercial (Santiago) orchards, showed differences in organic acids content and L-IdnDH gene expression. In general it was observed an increase in organic acids content, specifically tat1ar ic and malic acid, from the earliest stages until veraison stage, to then decrease toa basal leve!. These results could indicate a possible temperature effect on physiological features, as berry weight, affecting tartaric acid synthesis. Complementary, it was studied the potential influence of ethylene hormone during maturation process. It was observed a minor ac idity and organic acid content in grapes treated with exogenous ethylene compared to plants treated with a perception inhibitor (l-MCP) and without application. It was found no significant differences in the expression of L-IdnDH gene between between treatments during all stages studied. In conclusion, environmental factors and table grape properties, including the influence of ethylene in the maturation process, would modify tartaric acid synthesis and content.
The table grape (Vitis vinífera) is the main fruit of the chilean export fruit market. The organoleptic property is directly influenced by c limatological conditions as well as the genetic background of each cultivar. This feature is associated with soluble so lids/acidity ratio. Tartaric acid is the main organic acid in grapes being one of the major contributor to flavor and therefore, variations in concentration it could affect the palatability perceived by the consumer. In this work, was established the hypothesis established was that tartaric acid synthesis is differentially regulated by the gene encoding L-Idonate Dehydrogenase enzyme in early development stages for different grape varieties. To this purpose, synthesized organic acids and L-Idonate Dehydrogenase gene expression (VvL-ldnDH) were quantified during the development of two commercial varieties of table grapes, in different geographical conditions and ethylene treatments. Rapes from orchards located in different regions, commercial (Los Andes and Quinta de Tilcoco) and semi-commercial (Santiago) orchards, showed differences in organic acids content and L-IdnDH gene expression. In general it was observed an increase in organic acids content, specifically tat1ar ic and malic acid, from the earliest stages until veraison stage, to then decrease toa basal leve!. These results could indicate a possible temperature effect on physiological features, as berry weight, affecting tartaric acid synthesis. Complementary, it was studied the potential influence of ethylene hormone during maturation process. It was observed a minor ac idity and organic acid content in grapes treated with exogenous ethylene compared to plants treated with a perception inhibitor (l-MCP) and without application. It was found no significant differences in the expression of L-IdnDH gene between between treatments during all stages studied. In conclusion, environmental factors and table grape properties, including the influence of ethylene in the maturation process, would modify tartaric acid synthesis and content.
Notas
Tesis (Magister en Biotecnología)
Proyecto FONDECYT No.1100273
Proyecto FONDECYT No.1100273
Palabras clave
Uva de Mesa, Vid, Ácido Tartárico, Chile