Arbuscular mycorrhizal symbiosis and other plant soil interactions in relation to environmental stress

Abstract

In this chapter, focused on the arbuscular mycorrhizal (AM) fungi and their mostly mutualistic association with the vast majority of herbaceous plant species, we examine the cellular, molecular, and physiological mechanisms by which the mycorrhizal symbiosis can enhance plant stress tolerance in relation to a number of abiotic environmental stressors, such as macro and micronutrient deficiency, drought, and metal toxicity. Overall, the primary mechanisms of interaction discussed here include: (1) the enhanced uptake of macro and micronutrients and water; and (2) the stabilization of the soil architecture via mycorrhizal-enhanced soil aggregation and metal biosorption processes. A key facet of this analysis involves the identification of direct vs. indirect benefits of interactions, and their distinctive impacts toward plant development as well as the proximal growth environment. Accordingly, due to the significant and widespread effects of these direct and indirect processes toward plant physiological and soil ecological function, it is suggested that the mycorrhizal symbiosis should constitute an extrinsic stress tolerance strategy that could complement the inherent resistance mechanisms of plants when subjected to an array of potential stressors, and also buffer the growth environment. For this reason, it is recommended that future studies take into account such multitrophic interactions (e.g., above and belowground relationships) to better depict physiological and ecological phenomena in relation to environmental stress.