Titolo della tesi: RUCOL-ITA. Genetic improvement of Italian rocket
Diplotaxis tenuifolia, known as wild rocket, is a highly valued leafy vegetable from the Brassicaceae family, with increasing importance in the food industry, particularly in Italy. The Piana del Sele region in Campania, the primary cultivation area, plays a pivotal role in Italy’s leadership in rocket production, as reflected in the Protected Geographical Indication (IGP) status of the local crop. The cultivation of D. tenuifolia faces significant challenges, including early flowering and susceptibility to soil-borne pathogens, which limit yield and market quality. These issues are particularly problematic in intensive farming systems, driving the need for innovative breeding approaches to enhance productivity and disease resistance. This thesis addresses these challenges through three main objectives: (1) to identify D. tenuifolia late-bolting lines with increased leaf productivity by studying the floral transition and creating a EMS-mutagenized population; (2) to improve resistance to biotic and abiotic stresses, particularly Fusarium wilt, by generating a high-quality reference genome and constructing a genetic map using an F2 population from a cross between two parental lines with differential resistance responses; and (3) to establish an Agrobacterium-mediated transformation protocol to enable genome editing in D. tenuifolia. The results obtained from these aims offer valuable insights: we characterized the molecular mechanisms of floral transition in D. tenuifolia, identifying key regulators and successfully identifying a stable late-flowering line (#91), which exhibited increased leaf productivity. Moreover, we identified Fusarium redolens as a pathogen of wild rocket in Southern Italy and provided evidence of differential resistance among D. tenuifolia lines. A high-quality genome reference and a genetic map were generated, laying the groundwork for future marker-assisted breeding. Finally, we developed an Agrobacterium-mediated transformation protocol using floral dip and drop by drop method, marking a crucial step towards genome editing applications for crop improvement.
In conclusion, this study advances our understanding of flowering time regulation, disease resistance, and genetic transformation in D. tenuifolia. The genomic and biotechnological tools developed here provide essential resources for breeding programs aimed at enhancing the resilience and productivity of rocket crops. Future work will focus on validating candidate genes for flowering time and Fusarium resistance, , and applying genome editing technologies to accelerate crop improvement.