Showing papers on "Mycovirus published in 2000"

A novel RNA mycovirus in a hypovirulent isolate of the plant pathogen Diaporthe ambigua.

Abstract: Hypovirulent isolates of the fruit tree fungal pathogen Diaporthe ambigua have previously been shown to harbour a double-stranded (ds)RNA genetic element of about 4 kb. In this study, we established the complete cDNA sequence of this dsRNA, which represents a replicative form of a positive-strand RNA virus that we have named D. ambigua RNA virus (DaRV). The nucleotide sequence of the genome is 4113 bp and has a GC content of 53%. Two large ORFs are present in the same reading frame. They are most probably translated by readthrough of a UAG stop codon in the central part of the genome. The longest possible translation product (p125) has a predicted molecular mass of about 125 kDa. A significant homology can be found to the non-structural proteins of carmoviruses of the positive-strand RNA virus family TOMBUSVIRIDAE: These proteins also include the conserved RNA-dependent RNA polymerase (RDRP) domain. In contrast to the genome organization of these plant viruses, no ORF is present at the 3' end of the DaRV genome that encodes a coat protein. Therefore, it is proposed that DaRV is not encapsidated but that it occurs as RNA-RDRP complexes and/or that it might be associated with cell membranes. Interestingly, six putative transmembrane helices are predicted in the N-terminal part of p56 (translation product of the first ORF, N-terminal part of p125), which might direct and anchor the viral complex to membranes. DaRV is a mycovirus with a unique genome organization and has a distant relationship to the plant virus family TOMBUSVIRIDAE:

Mycoviruses: A Novel Option for Managing Some Plant Diseases

Abstract: The term ‘mycovirus’ was coined using two words i.e mykos and virus literally meaning fungal viruses. These were not known before 1950 although their presence was suspected in some pathogenic fungi (Linderberge, 1959) Presence of virus particles in fungal body was first scientifically established with the dieback disease of cultivated mushrooms in 1962 (Gandy and Hollings, 1962; Hollings, 1962). Since then a large number of mycoviruses or similar agents have been isolated, purified and characterised from many species of fungi belonging to all major classes (Bozarath, 1972;Hollings and Stone, 1971;Lemke, 1980;Lemke and Nash, 1974). Mycoviruses have economic significance as many of the fungi in which they were found caused serious diseases in plants or used in the industry for the production of many essential commodities like mushrooms, toxins, antibiotics and medicine.