V. Jacobi et al., CLONING AND SEQUENCE-ANALYSIS OF RNA-2 OF A MECHANICALLY TRANSMITTED UK ISOLATE OF BARLEY MILD MOSAIC BYMOVIRUS (BAMMV), Virus research, 37(2), 1995, pp. 99-111
A mutant of the 'Streatley' isolate of barley mild mosaic bymovirus wa
s selected from the original field isolate by repeated mechanical inoc
ulation. Unlike the wild-type barley mild mosaic virus, which is trans
mitted by the soilborne fungus Polymyxa graminis, the mutant could not
be transmitted by this vector. RNA-2 of the mutant virus was shorter
than that of the wild-type virus suggesting that a deletion of part of
the genome segment had occurred. The nucleotide sequence of the mutan
t RNA-2 was determined and revealed a high degree of homology with the
RNA-2 of a German BaMMV field isolate. The deletion comprises 1092 nu
cleotides and is located in the 3'-terminal part of the coding region.
The 34-kDa truncated form of the C-terminal protein is less than half
the size of the corresponding protein of full-length BaMMV RNA-2 Take
n together, the sequence data and results of biological experiments su
ggest an essential role of the C-terminal protein for fungus transmiss
ion of BaMMV.