Studio del ruolo dei batteri associati alle radici nella protezione delle piante di pomodoro (Solanum lycopersicum L.) contro Spodoptera exigua e Botrytis cinerea

Plants are continuously exposed to different factors, such as climate change, drought, disease, and herbivory attacks. To overcome these problems, they evolved different strategies to warn the nearby plants of danger, to reduce the damage, and fight disease. Plants adopt the "cry-for-help" strategy in case of herbivory attack aboveground, by recruiting specific beneficial microbes, to protect plants themselves from the stress. Plant’s microbial recruitment involves, among other factors, the emission of volatile organic compounds (VOCs) in the surrounding environment. The beneficial microbes can help plants by promoting growth, enhancing nutrient uptake, and protecting them from pests and diseases. This thesis aimed to investigate the ability of specific bacteria to protect tomato plants (Solanum lycopersicum) against herbivory attack (Spodoptera exigua), by studying the effects of these beneficial microbes on the biomass and nutrient status of healthy tomato plants and, on the other side, the resistance to the caterpillars (L2 instar larvae stage, around 2 mm size) in the stressed plants. According to our hypothesis, the microbes helped to increase the plant biomass (aboveground and belowground) promoting the growth of healthy plants, and at the same time helping the plants to resist the caterpillar attack. Furthermore, the effect of the volatile compound identified (Methyl salicylate) on bacteria surface motility has been investigated. Results showed that such VOC promoted the spread of bacteria, highlighting its role in attracting beneficial microbes. In conclusion, this research may contribute to the development of new strategies for improving plant health and resistance, while reducing the need for harmful pesticides and fertilizers. By applying the power of the microbiome, we could ensure long-term soil health, reduce dependence on chemical inputs, and promote environmentally friendly farming methods. ​