LETTUCE 3.0 – FROM FARM TO LAB TO FORK: THE GENETIC BASES OF MICROBE-INDUCED PLANT RESILIENCE

The below- and aboveground compartments of plants are colonized by a wide variety of microorganisms that contribute to key biological processes and play a pivotal role in human nutrition and plant health. While their contributions to plant homeostasis and host nutrition are well-established, much remains to be understood about the factors shaping the structure and ecological functions of root- and leaf-associated microbial communities. Additionally, the extent to which plant genetic variability influences microbial community assembly and affects the plant's physiological response to soil microbial inoculation is still unclear. My doctoral research, titled “Lettuce 3.0 – From Farm to Lab to Fork: The Genetic Bases of Microbe-Induced Plant Resilience” is part of the Italian National Operational Programme (NOP) on Research and Innovation. This project, funded by the European Union, aims to develop sustainable agricultural strategies in support of the green transition. Specifically, my research seeks to enhance our understanding of the role microbial biodiversity plays in root and phyllosphere compartments, focusing on nutrient use efficiency and plant fitness, objectives closely aligned with the European Green Deal. Additionally, my work explores the contribution of plant genetic diversity to these processes. In order to address these gaps, we set up two large-scale experiments using 131 Lactuca sativa genotypes. By taking into account the metabolic (free amino acids, photosynthetic pigments, total soluble sugars and starch), phosphate and mineral content in leaves, we elucidated how microbial communities are shaped in these plant compartments and what is the interaction between plant genetic diversity and leaf nutritional state. Moreover, we took advantage of 16S rRNA data coming from roots and shoots to investigate the main factors driving microbial community networks and the plant genetic base of responsiveness to a soil inoculum. Overall, this study shed light on the mechanisms by which plants select their guests and respond to them, with a special focus on how plants' physiological and nutritional needs dictate this interplay.