In vitro antagonism evaluation of endophyte Chaetomium aureum against Cryphonectria parasitica

The European chestnut tree (Castanea sativa Mill.) is threatened by various microfungi that affect its production. In the trunk and branches infected by chestnut blight (Cryphonectria parasitica (Murril) Barr.) it was observed the presence of several microfungi that co-occur in the presence of the disease among which the endophytic fungus Chaetomium aureum Chivers. Many species of the genus Chaetomium are described as antagonists of plant fungi and various soil microorganisms, and the secondary metabolites of these species exhibit biological activities. The aim of this work was to study the antagonist activity of the fungus C. aureum against C. parasitica. The study was carried out under in vitro conditions by establishing co-cultures in PDA culture medium. Five repetitions were performed for each co-culture and the inner and outer radius of the colonies were measured for 10 days. The mycelial growth inhibition was expressed as percentage growth inhibition in relation to the control co-culture. The reduction of growth of the internal radius of C. parasitica by C. aureum was significant (P=0.02) after 10 days with an inhibition of 36.8%, and no contact was observed between colonies. This study highlights the importance of phytobiome in controlling chestnut trunk and branch diseases and the need to continue screening for fungal isolates that are candidates for natural disease control on chestnut.