RESUMO
Analysis of the nucleotide sequence of the RNA 1 of lilac leaf chlorosis virus (LLCV) supports a close relationship with subgroup 3 ilarviruses. LLCV RNA 1 consists of 3404 nucleotides (nt) and encodes a single open reading frame consisting of 3111 nt. The deduced protein (M(r) 117 kDa) contains the putative methyltransferase domain in the N-terminal region, and the NTPase/helicase domain in the C-terminal region. A conserved 41-nt region was identified at the distal end of the 3'UTR of all three genomic fragments of LLCV, with hairpin structures that may constitute putative coat protein binding sites.
Assuntos
Ilarvirus/genética , Ilarvirus/isolamento & purificação , Doenças das Plantas/virologia , Syringa/virologia , Sequência de Bases , Ilarvirus/química , Ilarvirus/classificação , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Fases de Leitura Aberta , Filogenia , RNA Viral/química , RNA Viral/genética , Análise de Sequência de DNARESUMO
RNA 2 and RNA 3 of lilac leaf chlorosis virus (LLCV) were sequenced and shown to be 2,762 nucleotides (nt) and 2,117 nts in length, respectively. RNA 2 encodes a putative 807-amino-acid (aa) RNA-dependent RNA polymerase associated protein with an estimated M (r) of 92.75 kDa. RNA 3 is bicistronic, with ORF1 encoding a putative movement protein (277 aa, M (r) 31.45 kDa) and ORF2 encoding the putative coat protein (221 aa, M (r) 24.37 kDa). The genome organization is similar to that typical for members of the genus Ilarvirus. Phylogenetic analyses indicate a close evolutionary relationship between LLCV, ApMV, and PNRSV.
Assuntos
Ilarvirus , Folhas de Planta/virologia , Proteínas do Movimento Viral em Plantas/genética , RNA Viral/genética , Análise de Sequência de DNA , Syringa/virologia , Proteínas Virais/genética , Ilarvirus/classificação , Ilarvirus/genética , Ilarvirus/isolamento & purificação , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Filogenia , Doenças das Plantas/virologia , Proteínas do Movimento Viral em Plantas/metabolismo , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Virais/químicaRESUMO
The satellite RNA of the grapevine isolate NW of Arabis mosaic virus (ArMV) was cloned and sequenced, and showed 75% identity at the nucleotide level to the satellite RNA of the lilac isolate of ArMV. In order to survey ArMV isolates from various geographical origins and natural hosts for the presence of large satellite RNAs and analyse their degree of variability, a RT/PCR-partial restriction enzymatic mapping (PREM) method was developed. The method is based on the incorporation of 5-methyl-dCTP in the RT/PCR reaction, and the subsequent digestion of the RT/PCR products by methyl-sensitive restriction enzymes. Satellites RNAs were detected by RT/PCR in eight isolates out of 47, six of them originating from grapevine, one from hop and one from lilac. The partial restriction digestion patterns allowed to distinguish six different types of satellites. Cloning and sequencing of the different satellites confirmed these results, the PREM proving able to discriminate sequences with 96% identity. The sizes of the different satellites varied between 1092 and 1139 nucleotides, their encoded proteins between 338 and 360 amino acids. Conserved domains were found in the amino and carboxy-termini between the sequences of the proteins encoded by the satellites of the different isolates of ArMV.
