Davis, Robert E.


Publications
21

Unraveling the Etiology of North American Grapevine Yellows (NAGY): Novel NAGY Phytoplasma Sequevars Related to ‘Candidatus Phytoplasma pruni’

Citation
Davis et al. (2015). Plant Disease 99 (8)
Names
Ca. Phytoplasma pruni
Abstract
North American grapevine yellows (NAGY) disease has sometimes been attributed to infection of Vitis vinifera L. by Prunus X-disease phytoplasma (‘Candidatus Phytoplasma pruni’) but this attribution may not be fully adequate. In this study, phytoplasma strains related to ‘Ca. Phytoplasma pruni’ were found in NAGY-diseased grapevines in Maryland, Pennsylvania, Virginia, Ohio, Missouri, and New York State. Based on restriction fragment length polymorphism analysis of 16S ribosomal RNA gene (16S rD

Should ‘Candidatus Phytoplasma’ be retained within the order Acholeplasmatales?

Citation
Zhao et al. (2015). International Journal of Systematic and Evolutionary Microbiology 65 (Pt_3)
Names
Ca. Phytoplasma
Abstract
Phytoplasmas are a diverse but phylogenetically coherent group of cell-wall-less bacteria affiliated with the class Mollicutes . Due to difficulties in establishing axenic culture, phytoplasmas were assigned to a provisional genus, ‘Candidatus Phytoplasma’, and the genus was embraced within the order Acholeplasmatales . Howe

‘Candidatus Phytoplasma palmicola’, associated with a lethal yellowing-type disease of coconut (Cocos nucifera L.) in Mozambique

Citation
Harrison et al. (2014). International Journal of Systematic and Evolutionary Microbiology 64 (Pt_6)
Names
Ca. Phytoplasma palmicola
Abstract
In this study, the taxonomic position and group classification of the phytoplasma associated with a lethal yellowing-type disease (LYD) of coconut (Cocos nucifera L.) in Mozambique were addressed. Pairwise similarity values based on alignment of nearly full-length 16S rRNA gene sequences (1530 bp) revealed that the Mozambique coconut phytoplasma (LYDM) shared 100 % identity with a comparable sequence derived from a phytoplasma strain (LDN) responsible for Awka wilt disease of coconut in Nigeria,

‘Candidatus Phytoplasma malaysianum’, a novel taxon associated with virescence and phyllody of Madagascar periwinkle (Catharanthus roseus)

Citation
Nejat et al. (2013). International Journal of Systematic and Evolutionary Microbiology 63 (Pt_2)
Names
Ca. Phytoplasma malaysianum
Abstract
This study addressed the taxonomic position and group classification of a phytoplasma responsible for virescence and phyllody symptoms in naturally diseased Madagascar periwinkle plants in western Malaysia. Unique regions in the 16S rRNA gene from the Malaysian periwinkle virescence (MaPV) phytoplasma distinguished the phytoplasma from all previously described ‘ Candidatus

‘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

Citation
Davis et al. (2013). International Journal of Systematic and Evolutionary Microbiology 63 (Pt_2)
Names
Ca. Phytoplasma pruni
Abstract
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

‘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.)

Citation
Davis et al. (2012). International Journal of Systematic and Evolutionary Microbiology 62 (Pt_4)
Names
Ca. Phytoplasma sudamericanum
Abstract
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 PCRs containing template DNAs extracted from diseased plants collected in Bonito (Pernambuco) and Viçosa (Minas Gerais) Brazil, indicated that such symptoms were associated with infections by two mutually distinct phytoplasmas. One phytoplasma, PassWB-

Phylogenetic positions of ‘Candidatus Phytoplasma asteris' and Spiroplasma kunkelii as inferred from multiple sets of concatenated core housekeeping proteins

Citation
Zhao et al. (2005). International Journal of Systematic and Evolutionary Microbiology 55 (5)
Names
Ca. Phytoplasma asteris
Abstract
Phytopathogenic mollicutes, which include spiroplasmas and phytoplasmas, are cell wall-less bacteria that parasitize plant hosts and insect vectors. Knowledge of the evolution of these agents is important in understanding their biology. The availability of the first complete phytoplasma and several partial spiroplasma and phytoplasma genome sequences made possible an investigation of evolutionary relationships between phytopathogenic mollicutes and other micro-organisms, especially Gram-positive