Barley yellow dwarf virus-GAV (BYDV-GAV) is a Chinese isolate and serologically related with BYDV-MAV, but they are not identical. Both are transmitted by Sitobion(Macrosiphum) avenae, but GAV is also transmitted by Schizaphis graminum. The complete nucleotide sequence of the genomic RNA of BYDV-GAV was determined and compared with other related viruses. Moreover, through RT-PCR fragments of the gene of movement protein (MP), i.e. ORF4 of genome of GAV, were obtained. Three deletion mutants of th...