A COMPREHENSIVE REVIEW ON MYCOVIRUSES AS BIOLOGICAL CONTROL AGENT

Mycoviruses are viruses that infect fungi. They have been reported in all major taxa of fungi. Generally extracellular phase is not present in mycoviruses and are transmitted during cell division intracellularly in sporogenesis, and/or hyphal anastomosis. The genome of mycoviruses has dsRNA, but a number of positive- or negative-strand ssRNA and ssDNA viruses have been isolated and characterized. There is an increasing interest for use of mycoviruses as novel biocontrol agent as they reduce the virulence of their phytopathogeinc fungal hosts. Mycoviruses can also infect endophytic fungi and encode killer toxins. Better understanding of mycoviruses assembly, function, and evolution have been done through their structural analyses. Recent report on virus taxonomy suggested that mycoviruses genome mostly consists of double-stranded RNA (dsRNA), and about 30% of mycoviruses genome is composed of a positive, single-stranded RNA (+ssRNA). Recently a mycovirus that is related to Gemini viruses has been reported. Scientists have reported mycoviruses in Chytridiomycota, Zygomycota, Ascomycota, Deuteromycota, and Basidiomycota. Many mycoviruses and their fungal hosts still remain unknown recently developed metagenomics approaches will be useful for detecting and identifying new mycoviruses