Potato late blight: prevention through innovative detection approaches and biocontrol using fungal-derived antimicrobials

Potato late blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases worldwide and a major threat to global food security. Currently, late blight management heavily depends on chemical fungicides, which lead to environmental concerns and pathogen resistance. In a context where sustainable and effective management strategies are needed, this thesis focused on two key aspects: (i) the development of a detection method using Nanopore amplicon sequencing for pathogen monitoring and (ii) the exploration of fungal-derived compounds from Trametes versicolor as a biocontrol approach against P. infestans. Nanopore amplicon sequencing allowed a quantitative method for detecting and monitoring P. infestans in potato plants, showing a strong correlation with quantitative PCR, and suggesting a promising tool for late blight early detection. The biocontrol study demonstrated the potential of T. versicolor culture filtrate (CF) with a strong antimicrobial effect against the pathogen, with high-molecular- weight protein compounds likely responsible for its bioactivity. When tested in planta, CF enhanced some defense-related responses, although no reduction in lesion size was observed. These findings highlight the potential of two control strategies for sustainable late blight management. Further studies should focus on characterizing the bioactive fungal compounds as well as understanding their mode of action, and validating Nanopore approach for in-field application.