Chromosome Sizes of Phytoplasmas Composing Major Phylogenetic Groups and Subgroups

Marcone, Carmine; Neimark, Harold; Ragozzino, A.; Lauer, Ulrich M.; Seemüller, E.

doi:10.1094/phyto.1999.89.9.805

Cited by 115 publications

(91 citation statements)

References 33 publications

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“…PFGE analysis revealed a chromosome size of 530 kbp for two BGWL isolates from southern Italy (Marcone et al, 1999). This value was confirmed by examining five other BGWL isolates that were collected at different locations in the same area (C. Marcone, unpublished results).…”

Section: Rflp Analysis Primer Specificity and Genome Sizementioning

confidence: 60%

‘Candidatus Phytoplasma cynodontis’, the phytoplasma associated with Bermuda grass white leaf disease

Marcone

Schneider

Seemüller

2004

International Journal of Systematic and Evolutionary Microbiology

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Bermuda grass white leaf (BGWL) is a destructive, phytoplasmal disease of Bermuda grass (Cynodon dactylon). The causal pathogen, the BGWL agent, differs from other phytoplasmas that cluster in the same major branch of the phytoplasma phylogenetic clade in <2?5 % of 16S rDNA nucleotide positions, the threshold for assigning species rank to phytoplasmas under the provisional status 'Candidatus'. Thus, the objective of this work was to examine homogeneity of BGWL isolates and to determine whether there are, in addition to 16S rDNA, other markers that support delineation of the BGWL agent at the putative species level. Phylogenetic analyses revealed that the 16S rDNA sequences of BGWL strains were identical or nearly identical. Clear differences that support separation of the BGWL agent from related phytoplasmas were observed within the 16S-23S rDNA spacer sequence, by serological comparisons, in vector transmission and in host-range specificity. From these results, it can be concluded that the BGWL phytoplasma is a discrete taxon at the putative species level, for which the name 'Candidatus Phytoplasma cynodontis' is proposed. Strain BGWL-C1 was selected as the reference strain. Phytoplasmas that are associated with brachiaria white leaf, carpet grass white leaf and diseases of date palms showed 16S rDNA and/or 16S-23S rDNA spacer sequences that were identical or nearly identical to those of the BGWL phytoplasmas. However, the data available do not seem to be sufficient for a proper taxonomic assignment of these phytoplasmas.Bermuda grass white leaf (BGWL) is a destructive phytoplasmal disease of Bermuda grass (Cynodon dactylon), which was first reported in Taiwan (Chen et al., 1972). The disease is known to occur in several Asian countries (Chen et al., 1972;Zahoor et al., 1995;Viswanathan, 1997;Sdoodee et al., 1999), Sudan (Dafalla & Cousin, 1988 and Italy . The most characteristic symptoms are extensive chlorosis, proliferation of axillary shoots, bushy growing habit, small leaves, shortened stolons and rhizomes, stunting and death of the plants. A similar disease, termed cynodon white leaf (CWL), has been reported in Australia. The causal agent appeared to be related closely or identical to the BGWL phytoplasma Tran-Nguyen et al., 2000;Blanche et al., 2003).Phytoplasmas associated with Bermuda grass diseases form, together with the agents of white leaf diseases of other gramineous plants [including Brachiaria distachya (brachiaria grass), Poa annua (annual blue grass) and probably Dactyloctenium aegyptum (growfoot grass)], the BGWL phytoplasma group or 16SrXIV-A group (Lee et al., 1998(Lee et al., , 2000 Seemüller et al., 1998;Sdoodee et al., 1999). There is evidence that phytoplasmas associated with diseases of date palms (Phoenix dactylifera) (Cronjé et al., 2000a, b) and carpet grass (Axonopus compressus) white leaf (CGWL) are related closely to this group. More distantly related to the Bermuda grass pathogens are the phytoplasmas that are associated with sugarcane white leaf (SCWL), sugarcane grassy shoot...

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Section: Rflp Analysis Primer Specificity and Genome Sizementioning

confidence: 60%

‘Candidatus Phytoplasma cynodontis’, the phytoplasma associated with Bermuda grass white leaf disease

Marcone

Schneider

Seemüller

2004

International Journal of Systematic and Evolutionary Microbiology

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“…The size of 'Ca. Phytoplasma' chromosomes ranges from 530 kbp to 1350 bp, as estimated from mobility on PFGE (Neimark & Kirkpatrick, 1993;Marcone et al, 1999).…”

Section: Description Of 'Candidatus Phytoplasma'mentioning

confidence: 99%

‘Candidatus Phytoplasma’, a taxon for the wall-less, non-helical prokaryotes that colonize plant phloem and insects

Group¹

2004

International Journal of Systematic and Evolutionary Microbiology

546

135

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The trivial name ‘phytoplasma’ has been adopted to collectively name wall-less, non-helical prokaryotes that colonize plant phloem and insects, which were formerly known as mycoplasma-like organisms. Although phytoplasmas have not yet been cultivated in vitro, phylogenetic analyses based on various conserved genes have shown that they represent a distinct, monophyletic clade within the class Mollicutes. It is proposed here to accommodate phytoplasmas within the novel genus ‘Candidatus (Ca.) Phytoplasma’. Given the diversity within ‘Ca. Phytoplasma’, several subtaxa are needed to accommodate organisms that share <97·5 % similarity among their 16S rRNA gene sequences. This report describes the properties of ‘Ca. Phytoplasma’, a taxon that includes the species ‘Ca. Phytoplasma aurantifolia’ (the prokaryote associated with witches'-broom disease of small-fruited acid lime), ‘Ca. Phytoplasma australiense’ (associated with Australian grapevine yellows), ‘Ca. Phytoplasma fraxini’ (associated with ash yellows), ‘Ca. Phytoplasma japonicum’ (associated with Japanese hydrangea phyllody), ‘Ca. Phytoplasma brasiliense’ (associated with hibiscus witches'-broom in Brazil), ‘Ca. Phytoplasma castaneae’ (associated with chestnut witches'-broom in Korea), ‘Ca. Phytoplasma asteris' (associated with aster yellows), ‘Ca. Phytoplasma mali’ (associated with apple proliferation), ‘Ca. Phytoplasma phoenicium’ (associated with almond lethal disease), ‘Ca. Phytoplasma trifolii’ (associated with clover proliferation), ‘Ca. Phytoplasma cynodontis' (associated with Bermuda grass white leaf), ‘Ca. Phytoplasma ziziphi’ (associated with jujube witches'-broom), ‘Ca. Phytoplasma oryzae’ (associated with rice yellow dwarf) and six species-level taxa for which the Candidatus species designation has not yet been formally proposed (for the phytoplasmas associated with X-disease of peach, grapevine flavescence dorée, Central American coconut lethal yellows, Tanzanian lethal decline of coconut, Nigerian lethal decline of coconut and loofah witches'-broom, respectively). Additional species are needed to accommodate organisms that, despite their 16S rRNA gene sequence being >97·5 % similar to those of other ‘Ca. Phytoplasma’ species, are characterized by distinctive biological, phytopathological and genetic properties. These include ‘Ca. Phytoplasma pyri’ (associated with pear decline), ‘Ca. Phytoplasma prunorum’ (associated with European stone fruit yellows), ‘Ca. Phytoplasma spartii’ (associated with spartium witches'-broom), ‘Ca. Phytoplasma rhamni’ (associated with buckthorn witches'-broom), ‘Ca. Phytoplasma allocasuarinae’ (associated with allocasuarina yellows), ‘Ca. Phytoplasma ulmi’ (associated with elm yellows) and an additional taxon for the stolbur phytoplasma. Conversely, some organisms, despite their 16S rRNA gene sequence being <97·5 % similar to that of any other ‘Ca. Phytoplasma’ species, are not presently described as Candidatus species, due to their poor overall characterization.

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“…In their evolutionary descent from walled bacteria in the Bacillus/ Clostridium group, phytoplasmas underwent extensive genome size reduction (Marcone et al, 1999;Oshima et al, 2004), losing genes that became unnecessary during adaptations to obligate, intracellular parasitism in plant and insect hosts (Davis et al, 2005). Due to the consequent inability to obtain pure cultures of phytoplasmas in vitro, properties used to distinguish and describe species of culturable bacteria, including culturable mollicutes, are largely unattainable for phytoplasmas.…”

mentioning

confidence: 99%

‘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

Davis

Zhao

Dally

et al. 2013

International Journal of Systematic and Evolutionary Microbiology

117

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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 distinct from those of previously described ‘Candidatus Phytoplasma ’ species. Nucleotide sequence alignments revealed that all studied X-disease phytoplasma strains shared less than 97.5 % 16S rRNA gene sequence similarity with previously described ‘Candidatus Phytoplasma ’ species. Based on unique properties of the DNA, we propose recognition of X-disease phytoplasma strain PX11CT1R as representative of a novel taxon, ‘Candidatus Phytoplasma pruni’. Results from nucleotide and phylogenetic analyses of secY and ribosomal protein (rp) gene sequences provided additional molecular markers of the ‘Ca. Phytoplasma pruni’ lineage. We propose that the term ‘Ca. Phytoplasma pruni’ be applied to phytoplasma strains whose 16S rRNA gene sequences contain the oligonucleotide sequences of unique regions that are designated in the formally published description of the taxon. Such strains include X-disease phytoplasma and - within the tolerance of a single base difference in one unique sequence - peach rosette, peach red suture, and little peach phytoplasmas. Although not employed for taxon delineation in this work, we further propose that secY, rp, and other genetic loci from the reference strain of a taxon, and where possible oligonucleotide sequences of unique regions of those genes that distinguish taxa within a given 16Sr group, be incorporated in emended descriptions and as part of future descriptions of ‘Candidatus Phytoplasma ’ taxa.

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Chromosome Sizes of Phytoplasmas Composing Major Phylogenetic Groups and Subgroups

Cited by 115 publications

References 33 publications

‘Candidatus Phytoplasma cynodontis’, the phytoplasma associated with Bermuda grass white leaf disease

‘Candidatus Phytoplasma cynodontis’, the phytoplasma associated with Bermuda grass white leaf disease

‘Candidatus Phytoplasma’, a taxon for the wall-less, non-helical prokaryotes that colonize plant phloem and insects

‘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

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