| genomic diversity and differentiation among phytoplasma strains in 16s rrna groups i (aster yellows and related phytoplasmas) and iii (x-disease and related phytoplasmas). | conserved gene sequences, including 16s rrna and ribosomal protein gene sequences, were used to evaluate genetic variations in phytoplasma strains belonging to 16s rrna groups i (aster yellows and related phytoplasmas) and iii (x-disease and related phytoplasmas). we used pcr to amplify the sequences of the 16s ribosomal dna and a segment of the ribosomal protein gene operon (encoding the 3' region of rps19, all of rp122, and rps3) from diverse phytoplasma group i and iii strains. additional chr ... | 1996 | 8573523 |
| physical map of the western x-disease phytoplasma chromosome. | a physical map of the chromosome of the western x-disease phytoplasma was constructed and represents the first physical map of a phytoplasma chromosome. the western x-disease phytoplasma is a nonculturable, plant-pathogenic member of the class mollicutes and is the causal agent of a severe disease of fruit trees in north america. the map was generated by performing restriction digests of the chromosome and resolving the restriction fragments by pulsed-field gel electrophoresis. southern blot ana ... | 1996 | 8682811 |
| an immunodominant membrane protein gene from the western x-disease phytoplasma is distinct from those of other phytoplasmas. | membrane proteins mediate several important processes, including attachment, in several mollicute species. phytoplasmas are non-culturable plant pathogenic mollicutes that are transmitted in a specific manner by certain phloem-feeding insect vectors. because it is likely that phytoplasma membrane proteins are involved with some aspect of the transmission process, their identification, isolation and characterization are important first steps in understanding phytoplasma transmission. a 32 kda imm ... | 2001 | 11238964 |
| expression of chloramphenicol acetyltransferase in bacillus subtilis under the control of a phytoplasma promoter. | a cloned putative promoter region upstream of the 16s rrna gene of the western x-disease phytoplasma was inserted behind the promoterless chloramphenicol acetyltransferase gene of plasmid ppl603. the dna construct was used to transform bacillus subtilis cells. the transformants were assayed for chloramphenicol acetyltransferase activity, showing that the phytoplasma promoter is efficiently expressed in a b. subtilis background. | 2001 | 11377863 |
| cosmid cloning and sample sequencing of the genome of the uncultivable mollicute, western x-disease phytoplasma, using dna purified by pulsed-field gel electrophoresis. | western x-disease (wx) phytoplasma is an uncultivable, intracellular pathogen of plants and insects with an at-rich genome of 670 kb. as part of the genome sequencing project of wx phytoplasma, we have cloned approximately 50% of its genome into the pcosrw2 cosmid vector using dna purified from pulsed-field gels. one of the cosmid clones with an insert of 24.6 kb was sequenced, which along with the cosmid end sequences, represents 60 kb of unique sequence from the wx phytoplasma genome. the puta ... | 2003 | 12725928 |
| construction of an interactive online phytoplasma classification tool, iphyclassifier, and its application in analysis of the peach x-disease phytoplasma group (16sriii). | phytoplasmas, the causal agents of numerous plant diseases, are insect-vector-transmitted, cell-wall-less bacteria descended from ancestral low-g+c-content gram-positive bacteria in the bacillus-clostridium group. despite their monophyletic origin, widely divergent phytoplasma lineages have evolved in adaptation to specific ecological niches. classification and taxonomic assignment of phytoplasmas have been based primarily on molecular analysis of 16s rrna gene sequences because of the inaccessi ... | 2009 | 19622670 |
| 'candidatus phytoplasma sudamericanum', a novel taxon, and strain passwb-br4, a new subgroup 16sriii-v phytoplasma, from diseased passion fruit (passiflora edulis f. flavicarpa deg.). | symptoms of abnormal proliferation of shoots resulting in formation of witches' broom growths were observed on diseased plants of passion fruit (passiflora edulis f. flavicarpa deg.) in brazil. rflp analysis of 16s rrna gene sequences amplified in polymerase chain reactions containing template dnas extracted from diseased plants collected in bonito, pe, and viçosa, mg, brazil, indicated that such symptoms were associated with infections by two mutually distinct phytoplasmas. one phytoplasma, pa ... | 2011 | 21669919 |
| 'candidatus phytoplasma pruni', a novel taxon associated with x-disease of stone fruits, prunus spp.: multilocus characterization based on 16s rrna, secy, and ribosomal protein genes. | x-disease is one of the most serious diseases known in peach (prunus persica). based on rflp analysis of 16s rrna gene sequences, peach x-disease phytoplasma strains from eastern and western united states and eastern canada were classified in 16s rrna gene rflp group 16sriii, subgroup a. phylogenetic analyses of 16s rrna gene sequences revealed that the x-disease phytoplasma strains formed a distinct subclade within the phytoplasma clade, supporting the hypothesis that they represented a lineage ... | 2013 | 22798643 |
| quantitative phenotyping of x-disease resistance in chokecherry using real-time pcr. | a quantitative real-time sybr green pcr (qpcr) assay has been developed to detect and quantify x-disease phytoplasmas in chokecherry. an x-disease phytoplasma-specific and high sensitivity primer pair was designed based on the 16s rrna gene sequence of x-disease phytoplasmas. this primer pair was specific to the 16sriii group (x-disease) phytoplasmas. the qpcr method can quantify phytoplasmas from a dna mix (a mix of both chokecherry and x-disease phytoplasma dna) at as low as 0.001 ng, 10-fold ... | 2014 | 24389037 |