Soybean mosaic virus (SMV) causes one of the most severe viral diseases in soybean ( Glycine max L.) and is known to contain many pathogenically and serologically related isolates. In the present study, the authors...Soybean mosaic virus (SMV) causes one of the most severe viral diseases in soybean ( Glycine max L.) and is known to contain many pathogenically and serologically related isolates. In the present study, the authors have obtained cDNAs to all cistrons of a Chinese SMV isolate, SMV_ZK, by RT_PCR. By analysing the nucleotide and amino acid sequence of the HC_PRO, NIb and CP cistrons, it was found that SMV_ZK was highly homologous to the G2 strain of SMV, thus confirming the existence of G2_like isolates in soybean crop in China. The amplified cDNAs were directly cloned into a bacterial expression vector. With the exception of the P3 cistron, expression of the cDNAs of all other cistrons in bacteria gave rise to polypeptides of expected molecular weight. The expressed viral proteins were subsequently purified by gel elution. The preparation of viral_specific cDNAs and gene products will be useful in future functional study of the SMV genome.展开更多
The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species. After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars a...The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species. After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars and tomato. A specific band of approximately 0.3 kb in length was amplified by RT PCR with primers synthesized based on reported CMV satellite RNA (satRNA) sequences. Sequence analysis showed there were two satRNAs (Sat P1 1 and Sat P1 2). Sat P1 1 contained 335 nucleotides, and Sat P1 2 contained 394 nucleotides. These two satRNAs shared 64% overall nucleotide sequence homology, and differences between the two satRNAs included mutations as well as deletions. Sat P1 1 was identical to a satRNA (Z96099) reported in 1995 in CMV P1. Based on differences in the sequence and secondary structure between these two satRNAs, we conclude that Sat P1 2 represents the emergence of a new satellite (necrotic satellite) from attenuated satRNA populations. The possible effect of the emergence of this new satRNA is discussed.展开更多
文摘Soybean mosaic virus (SMV) causes one of the most severe viral diseases in soybean ( Glycine max L.) and is known to contain many pathogenically and serologically related isolates. In the present study, the authors have obtained cDNAs to all cistrons of a Chinese SMV isolate, SMV_ZK, by RT_PCR. By analysing the nucleotide and amino acid sequence of the HC_PRO, NIb and CP cistrons, it was found that SMV_ZK was highly homologous to the G2 strain of SMV, thus confirming the existence of G2_like isolates in soybean crop in China. The amplified cDNAs were directly cloned into a bacterial expression vector. With the exception of the P3 cistron, expression of the cDNAs of all other cistrons in bacteria gave rise to polypeptides of expected molecular weight. The expressed viral proteins were subsequently purified by gel elution. The preparation of viral_specific cDNAs and gene products will be useful in future functional study of the SMV genome.
文摘The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species. After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars and tomato. A specific band of approximately 0.3 kb in length was amplified by RT PCR with primers synthesized based on reported CMV satellite RNA (satRNA) sequences. Sequence analysis showed there were two satRNAs (Sat P1 1 and Sat P1 2). Sat P1 1 contained 335 nucleotides, and Sat P1 2 contained 394 nucleotides. These two satRNAs shared 64% overall nucleotide sequence homology, and differences between the two satRNAs included mutations as well as deletions. Sat P1 1 was identical to a satRNA (Z96099) reported in 1995 in CMV P1. Based on differences in the sequence and secondary structure between these two satRNAs, we conclude that Sat P1 2 represents the emergence of a new satellite (necrotic satellite) from attenuated satRNA populations. The possible effect of the emergence of this new satRNA is discussed.
