National Research Council of Italy (CNR-IPSP), Italy
A central role of root symbionts: the plant response to environmental stresses
Soil bacterial and fungal communities serve as the first protection for plants. Rhizosphere and root-associated microorganisms improve plant growth and wellness, and the plant ability to interact and cooperate with them should be considered as a fundamental trait for achieving more stress-tolerant and climate-flexible crops. Environmental stressors can seriously reduce the growth and reproduction of plants, affecting the plant physiology and metabolism. Beneficial microorganisms activate specific stress-protective pathways that assist plant hosts to mitigate the negative effects of stresses, promoting multiple mechanisms of protection that counteract detrimental effects. Furthermore, environmental stresses can also compromise the association of plants with beneficial microbes, thereby significantly limiting the plant fitness. The molecular bases that underlie the improved plant tolerance mediated by soil microorganisms, as well as the decisions made by plants to engage with the appropriate microorganisms, are an area of intense research. Gleaned knowledge on this subject could in fact enable the development of crops that benefit more from the associated microbiota. Among root symbionts, the arbuscular mycorrhizal fungi undoubtedly play a relevant role in plant stress resilience processes, which will be here discussed in depth.