Can mycorrhizal symbiosis mitigate the adverse effects of climate change on crop production?

Abstract

Climate change, growing world population, and finite natural resources represent a sizable challenge to global food security. Increased temperature associated with more extreme rainfall, especially in the tropics, alters the relationships between crops, pests, pathogens, and weeds resulting in increased use of pesticides. This may promote contamination of agricultural soils by xenobiotics and potentially toxic metals (PTM). At the same time, aridity levels in many regions of the planet increase progressively, which will potentiate problems with drought and soil salinity. This situation harms the future sustainability and resilience of agricultural crops. Soil microorganisms perform various functions in the soil, improving plant nutrition and health, as well as soil quality, even in disturbed environments. Many economically important agricultural crops establish mutual symbiosis with arbuscular mycorrhizal fungi (AMF). AMF improvement to plants is derived from nutritional and nonnutritional effects. Such effects can ensure better yields in environments altered by climate change. In this chapter, we wish to highlight the potential of AMF for the maintenance of agroecosystems in environments modified by climate change, whether under drought stress, salinity stress, or soil contaminated by PTM or xenobiotics. AMF are ubiquitous, adapt to a wide variety of adverse environments, and therefore provide important ecosystem services. Under stress conditions, these fungi can improve water and nutrient uptake, plant growth and grain yield, and photosynthetic rate and promote biochemical and molecular changes in plant metabolism so that plants become more tolerant to biotic (pests, pathogens, nematodes) and abiotic (drought, salinity, PTM) stresses. In addition, AMF stimulate other microbial communities, increasing C sequestration in soil and, consequently, contributing to improvements in soil structure. In this scenario of climate change, exploring the wide range of these ecosystem services and their interaction with agricultural crops against finite natural resource and need to increase food production at the lowest environmental costs is a relevant question to ask. The results make evident the feasibility of the AMF application in drought conditions, high salinity, and in PTM- or xenobiotics-contaminated soils. The application of microbial biotechnology in agriculture has promoted many achievements; however, many barriers still have to be transposed for future sustainable agricultural development. From this, it is expected to be possible to exploit the AMF improvements to reduce agricultural inputs and promote food production even in the face of the climate change challenges.