Wheat yellow mosaic virus widely occurring in wheat (Triticum aestivum) inChina

Wheat yellow mosaic virus (WYMV) was identified in 25 of 27 wheat (Triticum aestivum) samples from six provinces in China using reverse-transcription polymerase chain reaction. Wheat spindle streak mosaic virus was not detect ed. Thus, contrary to previous reports, WYMV was the only bymovirus detecte d in wheat in China. The cDNA fragments corresponding to coat protein codin g regions of five WYMV isolates from China were cloned and sequenced. Deduc ed amino acid comparison of coat proteins among these five isolates, anothe r Chinese WYMV isolate HC, and one isolate from Japan showed very high sequ ence conservation, particularly in both the N- and C- termini. However, a h ighly virulent isolate HC from Henan Province showed four amino acid substi tutions in highly conserved amino acid positions which might play a role in its pathogenic variation.