High sequence conservation among cucumber mosaic virus isolates from lily

For classification of Cucumber mosaic virus (CMV) isolates from ornamental crops of different geographical areas, these were characterized by comparing the nucleotide sequences of RNAs 4 and the encoded coat proteins. Within the ornamental-infecting CMV viruses both subgroups were represented. CMV isolates of Alstroemeria and crocus were classified as subgroup II isolates, whereas 8 other isolates, from lily, gladiolus, amaranthus, larkspur, and lisianthus, were identified as subgroup I members. In general, nucleotide sequence comparisons correlated well with geographic distribution, with one notable exception: the analyzed nucleotide sequences of 5 lily isolates showed remarkably high homology despite different origins.

Characterization of potyviruses from tulip and lily which cause flower-breaking

Five viruses causing colour-breaking of tulip flowers were isolated from tulips and lilies. Tulip-breaking virus (TBV), tulip top-breaking virus (TTBV), tulip band-breaking virus, Rembrandt tulip-breaking virus and lily mottle virus were all characterized as potyviruses by serology and potyvirus-specific PCR. Sequence analysis of amplified DNA fragments spanning a conserved area of the coat protein cistron of potyviruses was performed in order to classify the isolates as distinct viruses or strains. It appears that all tulip-breaking viruses are distinct viruses and TTBV was found to be strain-related to turnip mosaic virus.

Some unusual serological reactions among potyviruses

The determination of relationships among and the identification of potyviruses with polyclonal antibodies does not always lead to a proper conclusion. The potyvirus specific monoclonal PTY 1 does not detect all potyviruses tested.

Relationships among iris severe mosaic virus (ISMV) isolates

The ISMV isolates studied so far, have been found to be indistinguishable both by serological and hybridization assays. Therefore, the different symptoms induced by these isolates may be based on only minor molecular changes.

Identification of potyviruses using the polymerase chain reaction with degenerate primers

Local areas of conserved amino acid sequence in the replicase and coat proteins of potyviruses were used to select nucleotide sequences for use in the construction of sets of degenerate oligonucleotide primers for amplification of DNA fragments on potyvirus-specific templates in a combined assay of reverse transcription and the polymerase chain reaction (RT-PCR). Sequences selected for the construction of degenerate primers included the coat protein gene sequence of tulip breaking virus from lily, which is reported in this paper. It is shown that the degenerate primers support potyvirus-specific amplification, but do not support amplification on carlavirus and potexvirus templates. A panel consisting of definite and prospective members of the potyvirus group occurring in bulbous crops was subjected to the degenerate primer RT-PCR assay; amplified fragments were used in cross-hybridization experiments and restriction fragment length polymorphism analysis to detect relationships among these potyviruses. A partially characterized virus isolated from Gloriosa rothschildiana was positively identified as a potyvirus by specific amplification and subsequent sequence analysis of an amplified DNA fragment.

Homologies between the genomes of a carlavirus (lily symptomless virus) and a potexvirus (lily virus X) from lily plants

cDNA clones complementary to the 3'-terminal regions of the genomic RNAs of the carlavirus lily symptomless virus and the potexvirus lily virus X (LVX) have been sequenced. The carlavirus RNA sequence contains five open reading frames (ORFs) coding for proteins of Mr 25,374, 11,631, 6960, 32,041 (coat protein) and 16,121, which are all very similar in size, amino acid sequence and relative position in the genome to proteins encoded by two different potato carlaviruses. The first four of these proteins also show considerable amino acid sequence similarity to proteins encoded by RNA of potexviruses, and the relative position of the ORFs on the carlavirus genome strongly resembles that in the potexvirus genomes. The LVX cDNA clone contains three ORFs encoding proteins of Mr 23,574, 11,767 and 21,569 (coat protein). A small ORF immediately 5' of the coat protein ORF, which has been found in other potexvirus genomes, is not present in the LVX genome. Thus, the data confirm the close taxonomic relationship between carlaviruses and potexviruses and reveal some differences in genome organization among the potexviruses.