Abstract:
Mycoviruses are common and have been reported to infect nearly all significant fungal taxonomic
groupings. Mycovirus neo-lifestyles have been revealed by the identification and characterization
of huge number of mycoviruses. This study reports an extensive screening survey on Pakistani
Botrytis cinerea (Fungal) strains for the identification of viral infections. A sum of 102 Botrytis
cinerea samples were screened, 9 isolates were found positive for mycoviral elements when
analyzed by a classical dsRNA isolation method with an infection frequency of 8.8%. Six isolates
(Kst5c, Kst10a, Kst14a, Kst31c, Kst32b & Kst33c) were subjected to Next-generation sequencing
for virome analysis. A total of 27 mycoviruses were identified in the infected isolates, belonging
to the families Endornaviridae, Fusariviridae, Botourmiavirdae, Narnaviridae and Mitoviridae.
Based on the International Committee on Taxonomy of Viruses (ICTV) demarcation criteria, 4
identified mycoviruses are considered novel. Viruses from three isolates (Kst5c, Kst14a &
Kst31c) were completely characterized and sequences have been submitted in the NCBI database.
Isolate Kst31c was found to harbor infection of hypovirulent mycovirus (BcEV4) which shows
debilitating effects in host fungus. Following genomic characterization, the biological assessment
was also conducted in which mycovirus was successfully transferred from virus-infected (VI)
strain to virus-free (VF) strain. Both said strains were vegetatively compatible because both
belong to same genetic group (Group II). Genetic grouping of all the B. cinerea isolates was
analyzed based on Bc-hch gene amplification followed by restriction digestion method. Isogenic
lines were compared later on, virus infected strain showed persistent infections due to presence of
mycovirus (BcEV4). Afterwards, pathogenicity tests were also performed which showed
promising results
