Hongos endófitos en sistemas agroforestalesevaluación de sus metabolitos secundarios con actividad antimicrobiana, antioxidante y reguladora del crecimiento vegetal

Abstract

Regarding the efforts to favour a more sustainable development of the dehesa ecosystem, the potential of endophytic fungi, those capable of asymptomatically colonizing plants tissues, was studied, due to their potential to establish symbiotic relationships with their hosts. To achieve this goal, we evaluated the potential of a selection of endophytic fungi, isolated in the dehesa, to produce in vitro secondary metabolites influencing plant growth promotion and protection against biotic and abiotic stresses. These fungi were first subcultured in liquid medium under standard conditions in order to test the applicability of the filtrates and crude extracts obtained. Subsequently, the biocontrol potential of these compounds was studied, both under in vitro and greenhouse conditions, against different microorganisms, such as Phytophthora cinnamomi, Botrytis cinerea and Pseudomonas syringae. The effect of the filtrates and the extracts on the growth of Lolium multiflorum, both under standard and salinity conditions, was also evaluated. At the same time, the possible sources of this beneficial effect, such as the production of compounds with phytohormonal or antioxidant activity, the mobilization of nutrients or the production of enzymes, was studied. Finally, with the fungi whose filtrates and extracts showed the most promising results, a first approach was made to the identification of the metabolites produced by HPLC techniques. This thesis has made it possible to identify different fungi capable of protecting the plant and promoting its growth through the production of a multitude of secondary metabolites that can help to reduce the use of chemical products.