Exploring the potential of microbial communities and bio-based solutions in improving plant tolerance and resilience to stresses

Climate change negatively affects agricultural production and environmental sustainability. In this scenario, the use of microorganisms has emerged as a promising tool for improving plants’ resilience to environmental stresses. This PhD thesis aimed to investigate the effect of beneficial microorganisms on soil health and crop productivity. In the first investigation, the impact of arbuscular mycorrhizal fungi was evaluated on pepper cultivation at varying water irrigation regimes, as well as the effect on the native soil microbial communities. The study suggested that a reduced irrigation under inoculation had a beneficial effect on pepper root associated microbes, while not impairing yield. The second experiment aimed to investigate the effect of plant growth-promoting bacteria inoculated in pea plants on plant productivity and natural soil-borne arbuscular mycorrhizal fungi and bacteria. Results showed that inoculation enhanced pea growth and production parameters and specific associated arbuscular mycorrhizal fungi and plant growth-promoting bacteria were identified. In the third investigation, the impact of different legume-based intercropping systems was tested on canola growth and productivity, as well as in shaping native bacterial communities. Results showed that legume choice is fundamental to improve canola growth in intercropping and that it drove specific associations between plants and putative root-associated plant growth-promoting bacteria. Additionally, the role of arbuscular mycorrhizal fungi and cover crops in restoring health in urban soils has been evaluated, analyzing the variations in anthropogenic volatile organic compounds. Results suggested that cover crops affected the degradation of anthropogenic volatile organic compounds, while arbuscular mycorrhizal fungi improved bacterial diversity, with an increase of soil health-related taxa. Overall, these studies highlighted the importance of microbial-based solutions in promoting plant growth in stressed environments.