Influence of crop load on the expression patterns of starch metabolism genes in alternate-bearing citrus trees
Fecha
2014Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión aceptada / Onetsi den bertsioa
Impacto
|
10.1016/j.plaphy.2014.03.032
Resumen
The fruit is the main sink organ in Citrus and captures almost all available photoassimilates during its development. Consequently, carbohydrate partitioning and starch content depend on the crop load of
Citrus trees. Nevertheless, little is known about the mechanisms controlling the starch metabolism at the tree level in relation to presence of fruit. The aim of this study was to find the relat ...
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The fruit is the main sink organ in Citrus and captures almost all available photoassimilates during its development. Consequently, carbohydrate partitioning and starch content depend on the crop load of
Citrus trees. Nevertheless, little is known about the mechanisms controlling the starch metabolism at the tree level in relation to presence of fruit. The aim of this study was to find the relation between the
seasonal variation of expression and activity of the genes involved in carbon metabolism and the partition and allocation of carbohydrates in ‘Salustiana’ sweet orange trees with different crop loads.
Metabolisable carbohydrates, and the expression and activity of the enzymes involved in sucrose and starch metabolism, including sucrose transport, were determined during the year in the roots and leaves
of 40-year-old trees bearing heavy crop loads ('on' trees) and trees with almost no fruits ('off' trees). Fruit altered photoassimilate partitioning in trees. Sucrose content tended to be constant in roots and
leaves, and surplus fixed carbon is channeled to starch production. Differences between 'on' and 'off' trees in starch content can be explained by differences in ADP-glucose pyrophosphorylase (AGPP)
expression/activity and a-amylase activity which varies depending on crop load. The observed relation of AGPP and UGPP (UDP-glucose pyrophosphorylase) is noteworthy and indicates a direct link between
sucrose and starch synthesis. Furthermore, different roles for sucrose transporter SUT1 and SUT2 have been proposed. Variation in soluble sugars content cannot explain the differences in gene expression
between the 'on' and 'off' trees. A still unknown signal from fruit should be responsible for this control. [--]
Materias
Alternate bearer,
Citrus,
Gene expression,
Enzyme activities,
Sinks,
Partition,
Fruit load
Editor
Elsevier
Publicado en
Plant Physiology and Biochemistry, 2014, 80, 105-113
Departamento
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Versión del editor
Entidades Financiadoras
This work has been partially supported by the Consellería de Cultura, Educació i Esport de la Generalitat Valenciana [GV/2007/213 and GV/2009/034], Comisión Interministerial de Ciencia y Tecnología
[BIO2010/18239] and Fondo Europeo de Desarrollo Regional [IIM01491.RI1].