Arbuscular Mycorrhizal Fungi for Enhanced Production and Crop Yield Under Changing Climate

Introduction

Improvements in the agricultural production capacity are expected to produce more to feed a growing population and to reap the benefits from the agricultural sector (Agnolucci et al., 2020). The challenges of the agroecosystem are increasingly getting serious. Farmers are faced with the problems of unpredictable climate change (Ait-El-Mokhtar et al., 2019a, 2020c), declining farmland, shrinking agricultural areas, depleted soil resources (Buras et al., 2020), lack of balanced soil nutrition, and declining crop responses to phytosanitary products (Olivares et al., 2019). As a result, concerns about the sustainable improvement of crop productivity and soil health are increasing (Garcia et al., 2019). Soil is the main source of nutrients and the true reservoir of bioresources for crop production and development (Kour et al., 2020). This ecosystem is rich in a wide variety of beneficial microorganisms that serve as active agents for carbon, nitrogen and phosphorus sequestration, recycling, and supplying for plants (Meglouli et al., 2019; Quiroga et al., 2020). The rhizosphere has many advantages for plants growth performance through microorganisms that improve phosphorus and nitrogen uptake (Zhang et al., 2018; Ben-Laouane et al., 2020b). Since soil productivity is declining and environmental stresses are significantly affecting agricultural production, plants productivity promotion and soil quality enhancement are key challenges to ensure sustainable agriculture for the world growing population (Agnolucci et al., 2020). However, to ensure better crop productivity in agricultural soils, chemical inputs are used regularly (Mahfudz et al., 2019) even if these fertilizers are not the optimal solution for maintaining sustainable crop productivity and soil fertility (Rivera-Becerril et al., 2017). To improve soil and crop productivity while minimizing chemical inputs, several potential biological practices were investigated. Among these, the use of arbuscular mycorrhizal fungi (AMF) as biofertilizers is getting considerable attention (Ben-Laouane et al., 2019; Ait-El-Mokhtar et al., 2020a; Anli et al., 2020b) and has to be better exploited to ensure sustainable agriculture (Boutasknit et al., 2020a; Meddich et al., 2020), reduced chemical inputs and protected crop and soil productivity (Anli et al., 2020a; Ben-Laouane et al., 2020b).

Soil fertility constitutes an important component in the ecosystem, and it is linked to higher enzymatic activity and soil microorganism’s abundance, which are indicators of soil biological quality (Gałązka et al., 2020). AMF play a crucial role in maintaining biological activities and soil stability (Ben-Laouane et al., 2020b; Gałązka et al., 2020). These microorganisms are able to colonize plant roots, including the most economically valuable crops such as fruit trees (Anli et al., 2020c), cereals (Bernardo et al., 2019), legumes (Ben-Laouane et al., 2019) and vegetables (Renaut et al., 2020). AMF have the capacity to enhance plant growth and production (Symanczik et al., 2018), absorb and translocate soil nutrients to the host plant roots (Boutasknit et al., 2020b), in exchange for carbon (Pan et al., 2020), and positively affect crop tolerance to environmental stresses (Anli et al., 2020a; Boutasknit et al., 2020b; Toubali et al., 2020). Furthermore, AMF symbiosis enhance plant physiology especially water content, leaf water potential and photosynthetic pigment as well as stomatal conductance (Symanczik et al., 2018; Boutasknit et al., 2020b).