RESUMEN
The host range of previously reported bymoviruses is restricted to plants belonging to the family Poaceae. Soybean leaf rugose mosaic virus (SbLRMV) from non-Poaceae plants is related to bymoviruses based on a partial genome sequence. However, unlike bymoviruses, this virus infects plants of at least four dicotyledonous families, including Fabaceae, and causes disease in soybean. Complete nucleotide sequences of two variants of SbLRMV were determined, and its taxonomic position was clarified. RNA1 is 7109 nucleotides (nt) long with one large open reading frame (ORF), possibly encoding a polyprotein of 257 kDa. This polyprotein is likely processed into eight mature proteins. The entire RNA1 ORF shares 52%-55% nucleotide sequence identity and 27%-43% amino acid sequence identity, and the coat protein shares 49%-54% nucleotide sequence identity and 30%-34% amino acid sequence identity to other bymoviruses. The similarity to other viruses in the family Potyviridae is generally lower. RNA2 is 3413 or 3415 nt long and putatively encodes a polyprotein of 108 kDa. This protein is probably cleaved into two mature proteins. The sequences of these two RNAs are very similar to those of bymoviruses. Phylogenetic analysis of members of the family Potyviridae showed that RNA1 and RNA2 of SbLRMV formed a basal clade with known bymoviruses. Inoculation tests using leaf samples suggested that SbLRMV RNA1 can systemically infect and cause disease in soybean without the presence of RNA2. In conclusion, SbLRMV is an atypical member of the genus Bymovirus that infects soybean (Fabaceae) and other dicots rather than gramineous hosts.
Asunto(s)
Secuencia de Bases/genética , Glycine max/virología , Virus del Mosaico/genética , Hojas de la Planta/virología , Potyviridae/genética , Genoma Viral/genética , Sistemas de Lectura Abierta/genética , Filogenia , Enfermedades de las Plantas/virología , Poliproteínas/genética , ARN Viral/genética , Análisis de Secuencia de ADN/métodos , Proteínas Virales/genéticaRESUMEN
Four hundred and fifty nine isolates of fluorescent pseudomonads were obtained from the leaves and roots of potato plants. Of these, 20 leaf isolates and 28 root isolates induced violacein production in two N-acylhomoserine lactone (AHL)-reporter strains-Chromobacterium violaceum CV026 and VIR24. VIR24 is a new reporter strain for long N-acyl-chain-homoserine lactones, which can not be detected by CV026. Thin-layer chromatography revealed that the isolates produced multiple AHL molecules. We compared the 16S rRNA gene sequences of these isolates with sequences from a known database, and examined phylogenetic relationships. The AHL-producing isolates generally separated into three groups. Group I was mostly composed of leaf isolates, and group III, root isolates. Group II comprised both leaf and root isolates. There was a correlation between the phylogenetic cluster and the AHL molecules produced and some phenotypic characteristics. Our study confirmed that AHL-producing fluorescent pseudomonads could be distinguished in the phyllosphere and rhizosphere of potato plants.