A new hypovirulence associated mycovirus from Fusarium spp. isolated from apple orchards
S. KULSHRESTHA (1), M. Sharma (1) (1) Shoolini University of Biotechnology and Management Sciences, India

Fusarium is a genus of filamentous fungi, known to be cosmopolitan having a broad host range. The availability of effective and environmental friendly control methods for plant pathogenic fungi is limited; therefore, utilizing a biological control method is a thoughtful choice. Numbers of strains within a species of fungi exits in nature; some are virulent whereas others are hypovirulent. The hypovirulent isolates have atleast two possibilities; they are genetically hypo virulent or are infected by mycoviruses. From phytopathological perspective, both of them are interesting as they could be developed as biocontrol agents. In the present investigation, an attempt was made to target dsRNA mycoviruses associated with Fusarium spp. responsible for hypovirulence. Fusarium was isolated from apple orchards using bait method and identified by sequencing of internal transcribed region (ITS). Phenotypic difference with respect to slow and abnormal growth of the target fungus was suspected to be the result of mycovirus infection. We identified a putative hypovirulent isolate that produced mild symptoms after inoculation on apple and pear. Curing of Fusarium for virus using cycloheximide treatment resulted in normal morphology, pigmentation and growth rate. Presence of mycoviral dsRNA was first confirmed by isolation of dsRNA elements using CF-11 chromatography followed by the sequencing. The pathogenicity of cured and uncured strains of isolated Fusarium spp. was tested on pear and apple. Fusarium strain cured for mycovirues was found to be more pathogenic as compared to uncured strain. This confirms the involvement of mycovirus for hypovirulence phenomenon in Fusarium spp.  

Abstract Number: P9-271
Session Type: Poster