Completion of the sequence of the Aspergillus fumigatus partitivirus 1 genome

Abstract

A Portuguese isolate of Aspergillus fumigatus was found to contain three double-stranded (ds) RNA elements ranging in size from 1.1 to 1.8 kbp and comprising the genome of a strain of Aspergillus fumigatus partitivirus 1 (AfuPV-1) previously thought to contain only the two largest dsRNA elements. The sequence of the smallest dsRNA element is described here, completing the sequence of the AfuPV-1 genome. Sequence analysis of the element revealed an open reading frame encoding a protein of unknown function similar in size and distantly related to elements previously identified in other members of the family Partitiviridae.

Fig. 1

Genomic organisation of AfuPV-1 and comparisons of the amino acid sequences of putative proteins encoded by dsRNA3 elements of representative partitiviruses. (a) Agarose gel electrophoresis of dsRNA elements extracted from A. fumigatus isolate 12/43 Molecular sizes are indicated on the left with numbers. (b) Schematic representation of the genome organisation of AfuPV-1A. AfuPV-1 dsRNAs 1, 2 and 3 each contain a single ORF (grey boxes) flanked by 5’- and 3’-UTRs (black lines). The dsRNA1 is 1779 bp long and contains an ORF that encodes a putative RdRp with a molecular mass (Mr) of 63 kDa. The dsRNA2 is 1623 bp long and contains an ORF that encodes a putative CP with a Mr of 48 kDa. The dsRNA3 is 1112 bp long and contains an ORF that encodes a protein of unknown function with a Mr of 29 kDa. (c) BLAST COBALT alignment of the amino acid sequences of the putative proteins of unknown function encoded by the smallest genomic dsRNA3 elements of Aspergillus fumigatus partitivirus-1A (AfuPV-1A; LR743535), Ustilaginoidea virens partitivirus 1 (UvPV-1; AGO04405), Gremmeniella abietina RNA virus-MS1 (GaRV-MS1; AII16003), Plasmopara viticola associated partitivirus 2 (PvAPV-2; QHD64806), Aspergillus ochraceous virus (AoV; AYP71820) and Plasmopara viticola associated partitivirus 10 (PvAPV-10; QHD64798). Accession numbers are shown in brackets above. In the sequence alignment, asterisks signify identical amino acid residues, colons signify highly conserved residues, and single dots signify less-conserved but related residues. (d) Alignment of the 5’- and 3’-UTRs of the coding strands of the three genomic segments of AfuPV-1A, where asterisks indicate identical nucleotides in the three elements and single dots signify conserved purines or pyrimidines