THE COMPLETE NUCLEOTIDE-SEQUENCE OF RNA-2 OF A FUNGALLY-TRANSMITTED UK ISOLATE OF BARLEY MILD MOSAIC BYMOVIRUS AND IDENTIFICATION OF AMINO-ACID COMBINATIONS POSSIBLY INVOLVED IN FUNGUS TRANSMISSION
E. Peerenboom et al., THE COMPLETE NUCLEOTIDE-SEQUENCE OF RNA-2 OF A FUNGALLY-TRANSMITTED UK ISOLATE OF BARLEY MILD MOSAIC BYMOVIRUS AND IDENTIFICATION OF AMINO-ACID COMBINATIONS POSSIBLY INVOLVED IN FUNGUS TRANSMISSION, Virus research, 40(2), 1996, pp. 149-159
The complete nucleotide sequence of RNA-2 of a fungally-transmitted UK
isolate of barley mild mosaic bymovirus (BaMMV isolate UK-F) was dete
rmined and compared with other published sequences, particularly UK-M,
an isolate derived from the same source but which has been mechanical
ly passaged for several years, has a deletion of about 1 kb and cannot
be fungally transmitted. From an alignment of the BaMMV RNA-2 encoded
protein with that for barley yellow mosaic bymovirus (BaYMV), several
regions of consistent homology were identified and extensive searches
made for similarities with the proteins of other fungally-transmitted
viruses, especially amongst the furovirus capsid readthrough proteins
which seem especially prone to deletion and which have already been i
mplicated in fungus transmission. The amino acid combinations ER (glut
amic acid-arginine) or QR (glutamine-arginine) were found consistently
in all of the viruses. They occurred in positions predicted to be on
the outside of the protein, and therefore available for interaction wi
th the fungus vector, and were also within the regions prone to sponta
neous deletion. In view of the lack of other structural or sequence ho
mologies, it is suggested that these motifs are strong candidates for
involvement in fungus transmission.