This project explores the enigmatic and cryptic world of mycoviruses, viruses that infect fungi, particularly focusing on their diversity in natural ecosystems. Mycoviruses were first recognized in the 1960s and 1970s as pathogens in cultivated mushrooms and various other fungi. They have been found to modify host behavior, including reducing host virulence, and some have even been employed as biological control agents against plant pathogens. The main objective of the present project is to unravel the diversity of mycoviruses within a collection of Rubiaceae endophytic fungi and unravel their evolutionary history with their hosts. Specific objectives involve identifying mycoviruses in the fungal collection, investigating phylogenetic relationships, and assessing the incidence of mycoviruses in relation to the plant and host fungus. A comprehensive methodology for fungal isolation, identification, and detection of mycoviruses, including advanced sequencing techniques and bioinformatic analyses will be utilized. The study's significance lies in shedding light on the understudied mycovirus diversity within natural ecosystems, potentially uncovering novel applications for mycoviruses in controlling plant pathogens. This research has practical implications for sustainable agriculture and plant health, with implications for the broader understanding of fungal-plant-virus interactions.