Plants constitute dynamic systems with different strategies to face biotic and abiotic stress. Water deficit is one of the most challenging abiotic factors increased by climate change, affecting seriously the quality of soils and crop yields, decreasing photosynthetic rate, increasing the accumulation of free radicals, and modifying root morphology. In this regard, the potential role of the host plant - arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria (PGPB) interactions within the rhizosphere in the alleviation of drought stress is being deeply studied. These symbiotic relationships not only allow a major nutrient and water uptake, but also could be integrated as a sustainable approach to improve the growth and productivity of crops under water scarcity conditions. A better comprehension of the mechanisms of these synergies between PGPB and AMF with plants is becoming an important key to develop effective applications of these natural symbiosis. In this work, the highlighted knowledge concerning these associations and their effect in the response of plants under drought stress have been reviewed, focusing on the interactions described in Solanaceae vegetables, one of the most relevant crops in the Mediterranean area.

Modern agriculture has boosted the production of food based on the use of pesticides and fertilizers and improved plant varieties. However, the impact of some such technologies is high and not sustainable in the long term. Although the importance of rhizospheres in final plant performance, nutrient cycling, and ecosystems is well recognized, there is still a lack of information on the interactions of their main players. In this paper, four accessions of pepper are studied at the rhizosphere and root level under two farming systems: organic and conventional. Variations in soil traits, such as induced respiration, enzymatic activities, microbial counts, and metabolism of nitrogen at the rhizosphere and bulk soil, as well as measures of root morphology and plant production, are presented. The results showed differences for the evaluated traits between organic and conventional management, both at the rhizosphere and bulk soil levels. Organic farming showed higher microbial counts, enzymatic activities, and nitrogen mobilization. Our results also showed how some genotypes, such as Serrano or Piquillo, modified the properties of the rhizospheres in a very genotype-dependent way. This specificity of the soil–plant interaction should be considered for future breeding programs for soil-tailored agriculture.