Biological control of chestnut blight. Detection, identification and characterization of the Hypovirus - CHV1.

The chestnut blight caused by the fungus Cryphonectria parasitica is considered a major cause of the decline and disappearance of chestnut trees across Europe. C. parasitica is an ascomycete fungus (Diaporthales) that is native to eastern Asia. Infection of chestnut plants with this fungus is typically associated with extensive necrosis (cankers) of the bark on stems and branches, resulting in the subsequent death of the tree. Hypovirulence is a specific method for biological control of Chestnut Blight, it is an infection of C. parasitica with Cryphonectria hypovirus 1 (CHV1), a unencapsidate dsRNA virus of the genus Hypovirus. Biological control with hypovirulent strains is considered an efficient method to control the disease and improve the host plant recovery. The field application needs laboratorial production of compatible hypovirulent strain and introduction by inoculation at the margin of active cankers. In this work it was intended to identify and characterize the hypovirus with potential ability to integrate biological control programmes against Chestnut Blight. Using molecular techniques 11 hypovirus with hypovirulence potential were identified on white isolates of C. parasitica isolated on cankers from northeast of Portugal.