Papel del glutatión en la biología reproductiva del olivo

Reactive oxygen species (ROS) play important roles in plant physiology. Historically, they have been known because of their accumulation as a consequence of different stresses, even triggering cell damage. However, they are also presently known because of their beneficial and necessary functions (i.e. signaling), which are beginning to be described in plant reproductive processes. Cells display a complex network of antioxidants, composed by both enzymes and non-enzymatic molecules preventing excessive accumulation of ROS which may cause damage to biomolecules. Glutathione is a low molecular multifunction metabolite playing a critical antioxidant function, contributing to redox signaling, modulation of gene expression and the regulation of different enzyme activities. However, little is known regarding its regulative role in the plant reproductive processes. Glutathione is synthetized through the sequential action of γ-glutamyl-cysteine synthetase (γ-ECS) and glutathione synthetase (GS). A broad metabolic network is responsible of maintaining redox homeostasis as well as of keeping a high level of glutathione at the reduced state (GSH), which is the main form within the cell. The glutathione reductase enzyme (GR) is responsible of reducing oxidized glutathione (GSSG) to GSH, which will be used by glutathione peroxidase (GPX) and glutathione S-transferase (GST) enzymes to detoxify ROS and conjugate to xenobiotics, respectively. The main objective of the present thesis is focused into the analysis of the physiological role of glutathione and the enzymes involved in its metabolism into the different stages of the reproductive process of the olive tree, one of the most important crops in Spain. With this aim, new genomic and proteomic approaches have been used and the expression of the most relevant gene products has analyzed, as well as their activity, molecular characteristics and cell localization by using a broad panel of molecular, biochemical and cell methods available. Analyses have been performed using olive ...