Harnessing symbiotic plant–fungus interactions to unleash hidden forces from extreme plant ecosystems

The global climate change is arguably one of the biggest threats of our times that already led to a wide range of impacts on the environment, economy, and society. Due to past emissions and the inertia of the climate system, global climate change is estimated to continue for decades even though anthropogenic greenhouse gas emissions could be stopped immediately. In many regions, such as central Europe and the Mediterranean region the temperature is likely to rise by 2-5 masculineC and annual precipitations are assumed to decrease. Expected heat and drought periods followed by floods, and unpredictable growing seasons are estimated to have detrimental effects on the agricultural production system, causing immense economic losses and problems of food supply. To mitigate the risks provoked by the climate change, agricultural innovations counteracting these effects need to be embraced and accelerated. To achieve maximum improvements, the required agricultural innovations should not focus on the crop side alone, but rather pursue a holistic approach including the entire ecosystem. Over millions of years, plants have evolved in close association with other organisms, in particular with soil microbes that shaped their evolution and contemporary ecology. Many studies already highlighted beneficial interactions among community members, but will it be possible to decipher common molecular pattern and the underlying biochemical framework of interspecies communication? And will we be able to harness the obtained discoveries to improve agricultural performance under environmental stress conditions? In this review, we aim to summarize the current knowledge on plant interactions with fungal endosymbionts found in extreme ecosystems. Special attention will be paid to the interaction of plants with the symbiotic, root-colonizing endophytic fungus Serendipita indica, which has developed to a model system for beneficial plant-fungus interactions.