A Genotype-Based System for Identification and Classification of Mycoplasmalike Organisms (MLOs) in the Aster Yellows MLO Strain Cluster

Lee, I. M.; Davis, R. E.; Chen, T. A.; Chiykowski, L. N.; Fletcher, Jacqueline; Hiruki, C.; Schaff, Dennis A.

doi:10.1094/phyto-82-977

Cited by 78 publications

(42 citation statements)

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“…Indeed, they can be identified readily and defined based on RFLP patterns of the 16S rRNA, rp and tuf gene sequences. Such distinctions are consistent with relative homology of total genomic DNA (Lee et al, 1992).…”

Section: Resultssupporting

confidence: 77%

‘Candidatus Phytoplasma asteris’, a novel phytoplasma taxon associated with aster yellows and related diseases

Lee¹,

Gundersen‐Rindal

Davis³

et al. 2004

International Journal of Systematic and Evolutionary Microbiology

339

289

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Aster yellows (AY) group (16SrI) phytoplasmas are associated with over 100 economically important diseases worldwide and represent the most diverse and widespread phytoplasma group. Strains that belong to the AY group form a phylogenetically discrete subclade within the phytoplasma clade and are related most closely to the stolbur phytoplasma subclade, based on analysis of 16S rRNA gene sequences. AY subclade strains are related more closely to their culturable relatives, Acholeplasma spp., than any other phytoplasmas known. Within the AY subclade, six distinct phylogenetic lineages were revealed. Congruent phylogenies obtained by analyses of tuf gene and ribosomal protein (rp) operon gene sequences further resolved the diversity among AY group phytoplasmas. Distinct phylogenetic lineages were identified by RFLP analysis of 16S rRNA, tuf or rp gene sequences. Ten subgroups were differentiated, based on analysis of rp gene sequences. It is proposed that AY group phytoplasmas represent at least one novel taxon. Strain OAY, which is a member of subgroups 16SrI-B, rpI-B and tufI-B and is associated with evening primrose (Oenothera hookeri ) virescence in Michigan, USA, was selected as the reference strain for the novel taxon 'Candidatus Phytoplasma asteris'. A comprehensive database of diverse AY phytoplasma strains and their geographical distribution is presented.

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Section: Resultssupporting

confidence: 77%

‘Candidatus Phytoplasma asteris’, a novel phytoplasma taxon associated with aster yellows and related diseases

Lee¹,

Gundersen‐Rindal

Davis³

et al. 2004

International Journal of Systematic and Evolutionary Microbiology

339

289

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“…Four Japanese MLOs, including the onion yellows, tomato yellows, mulberry dwarf, and paulownia witches' broom agents (24) (the onion yellows MLO [MLO-I] was included in this study), are phylogenetically identical and exhibit the same levels of homology with strains M Y , OAY, and SAY (>99% sequence similarity). These strains correspond to strain type I1 of the aster yellows MLO strain cluster defined by Lee et al (17,18), which is characterized by an HhaI site after position 1253 that is not present in other MLOs. All of these strains also produce identical AZuI and RsaI restriction profiles and are members of RFLP group I of Schneider et al (27).…”

Section: Resultsmentioning

confidence: 64%

“…Most of this work has been reviewed by Kirkpatrick (10) and Lee and Davis (16). Closely related MLOs belonging to the aster yellows strain cluster could be classified by Southern blot analysis (17).…”

mentioning

confidence: 99%

Phylogenetic Classification of Phytopathogenic Mollicutes by Sequence Analysis of 16S Ribosomal DNA

Seemüller

Schneider

Mäurer

et al. 1994

International Journal of Systematic Bacteriology

228

136

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The phylogenetic relationships of 17 phytopathogenic mycoplasmalike organisms (MLOs) representing seven major taxonomic groups established on the basis of MLO 16s ribosomal DNA (rDNA) restriction patterns were examined by performing a sequence analysis of the 16s rDNA gene. The sequence data showed that the MLOs which we examined are members of a relatively homogeneous group that evolved monophyletically from a common ancestor. In agreement with results obtained previously with other MLOs, our results also revealed that the organisms are more closely related to AchoZepZasma Zaidhwii and other members of the anaeroplasma clade than to any other mollicutes. A phylogenetic tree based on 16s rDNAs showed that the MLOs which we examined can be divided into the following five primary clusters: (i) the aster yellows strain cluster; (ii) the apple proliferation strain cluster; (iii) the western-X disease strain cluster; (iv) the sugarcane white leaf strain cluster; and (v) the elm yellows strain cluster. The aster yellows, western-X disease, and elm yellows strain clusters were divided into two subgroups each. MLOs whose 16s rDNA sequences have been determined previously by other workers can be placed in one of the five groups. In addition to the overall division based on 16s rDNA sequence homology data, the primary clusters and subgroups could be further defined by a number of positions in the 16s rDNAs that exhibited characteristic compositions, especially in the variable regions of the gene.Nonhelical phytopathogenic mollicutes, which are most often referred to as mycoplasmalike organisms (MLOs), are wall-less, nonculturable prokaryotes that cause diseases in several hundred plant species (23). The first attempts to differentiate and classify these organisms were based on symptoms, host ranges, and insect vector relationships (4, 9, 21).The phylogenetic interrelatedness of the MLOs was poorly understood until recently, when molecular methods were introduced into plant mycoplasmology. Many MLO strains were differentiated and partially characterized by dot and Southern hybridization techniques, as well as by serological techniques. Most of this work has been reviewed by Kirkpatrick (10) and Lee and Davis (16). Closely related MLOs belonging to the aster yellows strain cluster could be classified by Southern blot analysis (17).Neither serological methods nor nucleic acid hybridization experiments performed with randomly cloned DNA fragments have revealed the phylogenetic or taxonomic positions of MLOs in relation to each other and to other microorganisms. In contrast, the 16s rRNA gene is a universal characteristic in prokaryotes and has both conserved and sufficiently variable regions. This gene is therefore suitable for phylogenetic and taxonomic classifications at various levels, including intrageneric differentiation (30,34 yellows agent (strain SAY), and the western-X disease agent (strain WX), as well as several Japanese MLOs, showed that these organisms exhibit levels of sequence homology of at least 89.4%. Thus...

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“…However, until more information is available on specific separation or identification of these various plant pathogens, some type of informal and revisable grouping scheme, such as that proposed in this paper, is appropriate for classification. The substantial molecular data (19,20,22,23,27) now available, including our results, may provide important insights into ecological distribution (33), taxonomy, and molecular diagnosis of MLOs (33) and in vitro culture. The presence (+) or absence (-) of a sequence in the 16s rRNA gene from an MLO was determined by comparison with existing oligonucleotide catalogs (-), very rare.…”

Section: A G Tmentioning

confidence: 68%

Phylogenetic Diversity of Phytopathogenic Mycoplasmalike Organisms

Namba

Oyaizu

Kato

et al. 1993

International Journal of Systematic Bacteriology

127

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By using specific primers, the 16s rRNA genes of Japanese mycoplasmalike organisms (MLOs) were amplified by polymerase chain reactions from MLO-enriched fractions of plants infected with each of six different MLOs. Each of the polymerase chain reaction fragments (length, 1,370 nucleotides) was directly sequenced in both strands by using 17 oligonucleotide primers. A phylogenetic tree constructed by using the sequence data showed that these Japanese MLOs are phylogenetically diverse microorganisms that fall into three groups, group I (onion yellows, tomato yellows, mulberry dwarf, and paulownia witches' broom MLOs), group 11 (tsuwabuki witches' broom MLO), and group I11 (rice yellow dwarf MLO). A high level of sequence homology (WO) between the Oenothera hookeri MLO and the severe strain of the western aster yellows MLO on the one hand and group I MLOs on the other indicates that the 0. hookeri MLO and the severe strain of the western aster yellows MLO belong to group I and suggests that these MLOs, isolated from two geographically separated locations, descended from a very similar ancestor. Although group I contains phylogenetically identical MLOs, the organisms are transmitted by diverse insect vectors. The three MLO groups are more closely related to Acholeplasma hidhzwii than to Mycoplasma gallisepticum. Thus, although MLOs are phylogenetically diverse, they are evolutionarily distant from other mollicutes. These data, together with other information (including phylogenetic relationships, vector specificity, plant-pathogenic properties, and habitat in plant phloem sieve tubes), suggest that MLOs could be classified into at least three phylogenetic groups (groups I through 111).

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A Genotype-Based System for Identification and Classification of Mycoplasmalike Organisms (MLOs) in the Aster Yellows MLO Strain Cluster

Cited by 78 publications

References 0 publications

‘Candidatus Phytoplasma asteris’, a novel phytoplasma taxon associated with aster yellows and related diseases

‘Candidatus Phytoplasma asteris’, a novel phytoplasma taxon associated with aster yellows and related diseases

Phylogenetic Classification of Phytopathogenic Mollicutes by Sequence Analysis of 16S Ribosomal DNA

Phylogenetic Diversity of Phytopathogenic Mycoplasmalike Organisms

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