ABSTRACT
Sequence analysis of iris severe mosaic potyvirus genomic RNA revealed an unusual E/G cleavage site between the deduced large nuclear-inclusion protein and coat protein sequences. The latter showed an N-terminus of only 15 amino acids. The 3' non-translated region of the viral RNA was 340 nucleotides long.
Subject(s)
Potyvirus/genetics , RNA, Viral/genetics , Amino Acid Sequence , Base Sequence , Capsid/genetics , Cloning, Molecular , DNA, Viral , DNA-Directed RNA Polymerases , Introns , Molecular Sequence Data , Sequence Homology, Amino Acid , Viral Proteins/geneticsABSTRACT
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.
Subject(s)
Mosaic Viruses/classification , Nucleic Acid Hybridization , Plants/microbiology , SerotypingABSTRACT
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.
Subject(s)
Capsid/chemistry , Plant Viruses/isolation & purification , Polymerase Chain Reaction , RNA-Dependent RNA Polymerase/chemistry , Amino Acid Sequence , Base Sequence , Blotting, Southern , Capsid/genetics , Cloning, Molecular , DNA Probes , DNA, Viral/chemistry , Electrophoresis, Agar Gel , Gene Amplification , Gene Library , Molecular Sequence Data , Nucleic Acid Hybridization , Open Reading Frames , Plant Viruses/classification , Plant Viruses/genetics , Polymorphism, Restriction Fragment Length , RNA, Viral/chemistry , RNA-Dependent RNA Polymerase/genetics , Templates, Genetic , Transcription, GeneticABSTRACT
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.
Subject(s)
Plant Viruses/genetics , RNA, Viral/genetics , Viral Proteins/genetics , Amino Acid Sequence , Base Sequence , DNA, Viral/genetics , Molecular Sequence Data , Sequence Homology, Nucleic AcidABSTRACT
The role of motility in the colonization of potato roots by Pseudomonas bacteria was studied. Four Tn5-induced flagella-less mutants of the plant-growth-stimulating P. fluorescens WCS374 appeared to be impaired in their ability to colonize growing potato roots.