Plant symbioses with fungal endophytes: perspectives on conservation and sustainable exploitation of Mediterranean ecosystems

Mediterranean ecosystems have evolved under strong environmental changes and disturbances. Some of these actions have involved severe human modifications in water budgets and land usage. The ecosystems of arid zones like those of the Iberian Peninsula, have characteristics that make them exceptional. The features of the physical environment and the climate have shaped organisms to live in a limit environment. Mediterranean ecotones are true sources of stress adaptations in plants and animals. Recent studies have shown that symbioses with endophytes are of crucial importance in the distribution of plant communities worldwide. These symbioses are in many cases responsible for adaptation to environmental and biological stresses. The use of such plant symbiotic organisms is a new approach which will have a high potential for the sustainable improvement of the overall agricultural production and ecosystems management. We have found that plants adapted to sand dunes and salt marshes in Mediterranean ecosystems harbor a large biodiversity of fungal root endophytes. These fungi can reduce symptoms caused by root pathogens and protect against other environmental stresses. Recently metagenomic studies of desert plants have confirmed this rich mycobiota and evidenced the broad range of ecological functions that endophytes play in nature. Endophytes seem to be a key factor for the functioning of arid ecosystems, and are a potential source of biotechnological tools for the design of new approaches for a sustainable agriculture and ecosystem restoration.This work was supported with a grant from CICYT of the Spanish Ministry of Science and Innovation (AGL2008-00716/AGR)