marzo15Referencia

Plant Cell. 2014 Feb;26(2):565-84. doi: 10.1105/tpc.114.122721. Epub 2014 Feb 21

Autores

Ortiz-Marchena MI1, Albi T, Lucas-Reina E, Said FE, Romero- Campero FJ, Cano B, Ruiz MT, Romero JM, Valverde F.

Resumen

Flowering is a crucial process that demands substantial resources. Carbon metabolism must be coordinated with development through a control mechanism that optimizes fitness for any physiological need and growth stage of the plant. However, how sugar allocation is controlled during the floral transition is unknown. Recently, the role of a CONSTANS (CO) ortholog (Cr-CO) in the control of the photoperiod response in the green alga Chlamydomonas reinhardtii and its influence on starch metabolism was demonstrated. In this work, we show that transitory starch accumulation and glycan composition during the floral transition in Arabidopsis thaliana are regulated by photoperiod. Employing a multidisciplinary approach, we demonstrate a role for CO in regulating the level and timing of expression of the GRANULE BOUND STARCH SYNTHASE (GBSS) gene. Furthermore, we provide a detailed characterization of a GBSS mutant involved in transitory starch synthesis and analyze its flowering time phenotype in relation to its altered capacity to synthesize amylose and to modify the plant free sugar content. Photoperiod modification of starch homeostasis by CO may be crucial for increasing the sugar mobilization demanded by the floral transition. This finding contributes to our understanding of the flowering process.

Descripción

En este trabajo se ha descubierto una relación entre la movilización del carbono y el fotoperiodo analizándose la capacidad de liberar azúcares a partir de la amilosa y en concreto de la actividad de la almidón sintasa unida a gránulo (GBSS). De este modo, la amilosa generada antes de florecer podría utilizarse durante la transición floral como una fuente de azúcares necesarios para este proceso. En este sentido, en este trabajo se propone un mecanismo por el cual CONSTANS (CO) alteraría la expresión de GBSS ayudando a liberar grandes cantidades de azúcares durante la transición floral. Así, la misma señal fotoperiódica que activa la expresión de FT a través del regulador central CO es también responsable de la movilización de azúcares durante la transición floral. La GBSS, por tanto, tiene una gran influencia en la composición del gránulo de almidón y en su estructura, además de en la capacidad de las plantas de acumular y movilizar azúcares a partir de él.

grupo

REFERENCIA DEL GRUPO INVESTIGADOR

La Unidad de Desarrollo Vegetal está constituida por un grupo de investigadores del CSIC y de la Universidad de Sevilla que combinan diferentes aproximaciones para estudiar los mecanismos moleculares que controlan el desarrollo vegetal. La línea de investigación del Dr. Valverde se centra en los mecanismos que rigen el proceso de floración, en particular aquellos aspectos relacionados con la floración dependiente de la longitud del día o fotoperiodo y señales metabólicas. El grupo del Prof. Romero investiga los mecanismos que controlan la biosíntesis de almidón y azúcar y el papel del metabolismo de carbono en el desarrollo vegetal. Finalmente, las investigaciones del grupo de la Dra. Calonje se centran en esclarecer los mecanismos epigenéticos que controlan las distintas fases del desarrollo vegetal, en particular el papel que desempeñan las proteínas del grupo Polycomb (PcG) en este proceso. Para estos estudios, resulta crucial el uso de técnicas masivas de adquisición de datos (ómicas), por lo que se ha iniciado una estrecha colaboración con el Departamento de Informática e Inteligencia Artificial de la Universidad de Sevilla.

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