| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 USDA-ARS Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA
2 Insect Biocontrol Laboratory, Beltsville, MD 20705, USA
3 Dept Biologia, Difesa e Biotecnologie Agro-Forestali, University of Basilicata, 85100 Potenza, Italy
4 Biologische Bundesanstalt, Institut für Pflanzenschutz im Obstbau, D-69221 Dossenheim, Germany
Correspondence
I.-M. Lee
leeim{at}ba.ars.usda.gov
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTS AND DISCUSSIONREFERENCES |
|---|
The GenBank/EMBL/DDBJ accession numbers for the aster yellows phytoplasma strain OAY sequences are M30790 (16S rDNA) and M74770 (rpl22–rps3).
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTS AND DISCUSSIONREFERENCES |
|---|
; Marwitz, 1990; Lee et al., 2000). A pioneer phylogenetic study based on 16S rRNA and ribosomal protein (rp) gene sequences was the first to indicate that an aster yellows (AY) phytoplasma strain was related to Acholeplasma laidlawii, a member of the Mollicutes (Lim & Sears, 1989). Phylogenetic analyses of 16S rRNA gene sequences revealed that phytoplasmas form a large, discrete, monophyletic clade that belongs to the class Mollicutes (Kuske & Kirkpatrick, 1992; Namba et al., 1993; Gundersen et al., 1994; Seemüller et al., 1994). Thus far, 20 distinct subclades have been identified within the phytoplasma clade (Seemüller et al., 1998). Collective RFLP profiles, derived by analyses of 16S rDNA sequences, have delineated 15 distinct phytoplasma 16S rDNA (16Sr) groups that coincide with well-defined subclades (Lee et al., 1993b, 1998b; Montano et al., 2001). Gundersen et al. (1994) proposed that the phytoplasma clade should be recognized as a novel genus within the class Mollicutes and that each subclade (or 16Sr group) represents at least a species. Thus far, eight ‘Candidatus Phytoplasma’ species have been proposed (Zreik et al., 1995; Davis et al., 1997; White et al., 1998; Griffiths et al., 1999; Sawayanagi et al., 1999; Montano et al., 2001; Jung et al., 2002; Verdin et al., 2003).
The AY phytoplasma group (16SrI) comprises AY phytoplasma and numerous related phytoplasmas worldwide, representing the most diverse and widespread phytoplasma group (Lee & Davis, 2000; McCoy et al., 1989). Aster yellows, which attacks the China aster, Callistephus chinensis Nees, was widespread throughout the eastern United States at the turn of the 20th century (Kunkel, 1926). It was transmitted primarily by the aster leafhopper Macrosteles quadrilineatus Forbes (formerly Macrosteles fascifrons Stal.) and was later called Eastern aster yellows, in order to distinguish it from another AY disease that occurred in celery in California (Kunkel, 1932). The latter, which is called Western aster yellows, is spread by a wider range of insect vectors, induces different symptoms in plants and is distributed worldwide (Tsai, 1979). Eastern and Western AY diseases are now known to be associated with phytoplasmas that belong to the AY phytoplasma group (16SrI) subgroups A (16SrI-A) and B (16SrI-B), respectively. Today, the term ‘AY phytoplasmas' refers generally to phytoplasma strains that belong to subgroups 16SrI-A and 16SrI-B. However, in prior decades, numerous diseases characterized by symptoms similar to those caused by subgroup 16SrI-A and subgroup 16SrI-B strains were reported as AY, but the causal agents of those diseases could not be identified accurately, based on the biological criteria that were used at that time, such as symptoms or insect vectors. Through the use of molecular tools, it has become evident that many diseases are caused by phytoplasmas that are different from, but related closely to, AY phytoplasmas that are classified in subgroups 16SrI-A and 16SrI-B.
Strains in the AY phytoplasma group share 
97 % similarity in their 16S rDNA sequences, but substantial genetic variations are evident and they occupy diverse ecological niches (Gundersen et al., 1994; Seemüller et al., 1994, 1998). Thus, the widely diverse AY phytoplasma group may consist of more than one species. Based on composite RFLP patterns of 16S rDNA and the tuf gene, the AY group phytoplasmas have been differentiated into at least six distinct subgroups (Marcone et al., 2000), most of which occupy mutually exclusive ecological niches (Lee et al., 1998a). Recently, four additional subgroups that are associated with diseases in soybean, cherry and strawberry were identified (Jomantiene et al., 2002b; Lee et al., 2002; Valiunas, 2003).
This paper reports phylogenetic relationships among strains in the AY phytoplasma group, based on combined analyses using sequences from the 16S rRNA gene and the ribosomal protein operon (genes rps19 and rpl22). We describe the widespread 16SrI-B, rpI-B strain OAY (=MIAY), associated with Oenothera virescence in Michigan, USA, as a representative of a novel taxon, ‘Candidatus Phytoplasma asteris’.
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTS AND DISCUSSIONREFERENCES |
|---|
). The phytoplasma strains were previously characterized and identified on the basis of RFLP analysis of 16S rRNA or tuf gene sequences (Lee et al., 1993b, 1998b; Marcone et al., 2000). Total nucleic acid was extracted, according to Ahrens et al. (1993) or Lee et al. (1993a), from original natural host plants or experimentally infected periwinkle (Catharanthus roseus) plants.
|
; Schneider et al., 1995) followed by P1A/P7A (5'-ACGCTGGCGGCGCGCCTAATAC-3'/5'-CCTTCATCGGCTCTTAGTGC-3'), was used to amplify a DNA fragment (P1A/P7A PCR products, about 1·8 kbp) that extends from the 5' end of the 16S rRNA gene, through the intergenic spacer region, to the 3' end of the 23S rRNA gene. A nested PCR using the primer pair rpF1/rpR1 (Lim & Sears, 1992) followed by rp(I)F1A/rp(I)R1A (5'-TTTTCCCCTACACGTACTTA-3'/5'-GTTCTTTTTGGCATTAACAT-3') was used to amplify a phytoplasma DNA segment (about 1·2 kbp) of the rp operon that encompassed genes rpl22 and rps3. For PCR amplification, 38 cycles were conducted in an automated thermal cycler (MJ Research DNA Thermal Cycler PTC-200) with AmpliTaq Gold polymerase. PCR mixtures contained 1 µl undiluted DNA preparation, 200 µM each dNTP and 0·4 µM each primer. The following conditions were used: denaturation at 94 °C for 1 min (11 min for the first cycle), annealing for 2 min at 55 °C (50 °C for rp sequence amplification) and primer extension for 3 min (7 min in the final cycle) at 72 °C. Diluted (1 : 30) PCR product from the first amplification (1 µl) was used as the template in the nested PCR. PCR products (5 µl) were electrophoresed through 1 % agarose gel. PCR products of rp sequences were digested with AluI, MseI and Tsp509I. The restriction products were then separated by electrophoresis through 5 % polyacrylamide gel (12 % for MseI and Tsp509I digests of rp products).
Cloning of PCR products and sequencing of DNA.
PCR-amplified fragments of the 16S rRNA and rp genes were cloned and sequenced. P1A/P7A PCR products and rp(I)F1A/rp(I)R1A PCR products (about 1·2 kbp, containing rpl22–rps3 gene sequences) were purified by using a Qiaquick PCR Purification kit and cloned in Escherichia coli by using a TOPO TA cloning kit (Invitrogen), according to the manufacturers' instructions. Sequencing was performed with an automated DNA sequencer (ABI Prism model 377). The cloned nucleotide sequences were deposited in GenBank; accession numbers are given in Figs 1 and 2.
|
|
|
RESULTS AND DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTS AND DISCUSSIONREFERENCES |
|---|
] (Fig. 1
). Among the subclades within the phytoplasma clade, the AY subclade is related more closely to Acholeplasma palmae and A. laidlawii, members of the Anaeroplasma clade, than any other. The AY group strains shared 97–100 % 16S rDNA sequence similarity. The phylogenetic tree constructed by parsimony analysis of nearly full-length 16S rDNA sequences resolved at least six distinct phylogenetic lineages. Six are consistent with RFLP subgroups 16SrI-A (strains BB, PVM, HYDP, CHRYM, CHRY, Btsv2CarD5 and OnionD2), 16SrI-C (strains CPhA, CPhB, KVE and KVG), 16SrI-E (strains BBS1 and BBS3), 16SrI-F (strains ACLR-AY and CVB), 16SrI-K (strain STRAWB2) and 16SrI-O (strain SPS). One contained subgroups 16SrI-B (strains OAY, SAY, AY1, CabD3, AlfSt, Btsv2CarD3, PRIVC and HyPH1), 16SrI-D (strain PaWB), 16SrI-L (strain AV2192), 16SrI-M (strain AVUT) and 16SrI-N (strain IOWB). A previous study that used tuf gene sequences for phylogenetic analysis resolved the same six distinct lineages (Marcone, 2000).
The rp operon (rpl22 and rps3 genes) was more variable in sequence among members of the AY phytoplasma group than 16S rDNA. Some strains shared as little as 95·1 % sequence similarity with other members of the AY group. A phylogenetic tree, derived by analysis of the two rp gene sequences, delineated ten distinct phylogenetic lineages among 21 strains analysed (Fig. 2). Six corresponded to 16SrI subgroups 16SrI-C (strains KVG, KVE and CPh), 16SrI-D (strain PaWB), 16SrI-E (strain BBS3), 16SrI-F (strains ACLR and CVB), 16SrI-K (strain STRAWB2) and 16SrI-N (strain IOWB), respectively. One lineage contained subgroups 16SrI-B (strains OAY and PRIVC), 16SrI-L (strains AV2192 and AV976) and 16SrI-M (strain AVUT), whereas strain MBS (a member of subgroup 16SrI-B) formed a lineage that was divergent from the other members of 16SrI-B. Members of 16SrI-A (strains PVM, HYDP, CHRYM, CHRY, BB and GD1) were delineated into two distinct lineages (strain GD1 alone representing one). Phylogenetic analysis based on amino acid sequences of the two rp genes resolved the same lineages as those delineated by analysis of nucleotide sequences (data not shown).
The ten distinct lineages that were delineated by phylogenetic analysis of rp gene sequences were differentiated readily by RFLP analyses of rp sequences, which provided a better molecular tool than the 16S rRNA gene for differentiation among closely related phytoplasma strains. Composite profiles obtained from digests with the restriction enzymes MseI, Tsp509I and AluI differentiated the AY group into ten distinct rp subgroups (Fig. 3 and Table 1), consistent with the ten phylogenetic lineages that were delineated by rp gene sequence-based phylogeny.
|
), reinforced the notion that most subgroups that were identified by RFLP analysis of 16S rDNA sequences represent distinct phylogenetic lineages. For example, strains PaWB (subgroup 16SrI-D) and MBS (subgroup 16SrI-B), which share >98 % 16S rRNA gene sequence similarity with members of subgroup 16SrI-B, were clustered with 16SrI-B strains in the 16S rRNA based-phylogeny, but the rp-based phylogeny indicated clearly that they represented two distinct lineages (bootstrap values, 99–100 %). In nature, strain PaWB is associated with paulownia witches'-broom disease in south-eastern Asia and strain MBS is associated with maize bushy stunt in the Americas. These two strains share neither insect host nor plant host, and their specific hosts differ from those of the other members of subgroup 16SrI-B. In light of such substantial differences in biological properties, it seems that members of group 16SrI represent more than one biological species. For example, members of subgroups 16SrI-D, 16SrI-E, 16SrI-F, 16SrI-K and 16SrI-N occupy uniquely different ecological niches in nature; they are associated with specific plant and insect hosts and/or are restricted to isolated geographical regions. For practical diagnostic and quarantine purposes, it would be advantageous if such biologically divergent organisms could be designated as distinct taxonomic entities. 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).
It is evident from the present and other work that many mutually distinct phytoplasma strains fall into a category in which, according to the International Committee of Systematic Bacteriology Subcommittee on the Taxonomy of Mollicutes (ICPRM, 2000), additional biological and genomic criteria are needed to describe a strain that has 16S rRNA gene sequence dissimilarity of <2·5 % with a previously described species as a novel ‘Candidatus Phytoplasma’ species. A phylogenetic parameter, such as the rp operon, that is more variable than the 16S rRNA gene may aid phytoplasma speciation. Designation of multiple species in group 16SrI is deferred until genetic divergence among the lineages can be evaluated further, in order to improve criteria for distinguishing closely related species in this group. Here, we propose that a novel ‘Candidatus Phytoplasma’ species should be designated and that strain OAY (=MIAY) should serve as the reference strain of the AY phytoplasma group.
Properties of ‘Candidatus Phytoplasma asteris’
Biological properties and geographical distribution.
The ‘Candidatus P. asteris' concept encompasses all known subgroups within group 16SrI. Strains that belong to subgroups 16SrI-A, 16SrI-B and 16SrI-C are distributed worldwide, are associated with more than 80 plant species and can be transmitted by more than 30 species of insect vectors (Kunkel, 1926; Brcák, 1979; Tsai, 1979). Subgroup 16SrI-B represents the largest and most diverse strain cluster in the group. Subgroups 16SrI-L and 16SrI-M appear to be restricted to the European continent. Experimentally, North American AY phytoplasmas (subgroups 16SrI-A and 16SrI-B) have been transmitted by insect vectors to 191 plant species, belonging to 42 families (McCoy et al., 1989). Some vectors are shared by members of subgroups 16SrI-A, 16Sr-B and 16SrI-C. Leafhoppers, Macrosteles spp., Euscelis spp., Scaphytopius spp. and Aphrodes spp. are the major vectors of AY phytoplasma strains (Brcák, 1979; Tsai, 1979; Chiykowski, 1991). Other subgroups in group 16SrI are each associated with a narrow range of plant and insect hosts and the diseases they cause are often restricted to certain geographical areas. For example, the subgroup 16SrI-D phytoplasma associated with paulownia (Paulownia taiwaniana and Paulownia tomentosa) is found in Asia. The vast majority of strains in the AY phytoplasma group infect herbaceous dicot plant hosts. However, a number of strains that belong to subgroups 16SrI-A, 16SrI-B and 16SrI-C are capable of infecting monocot plants (e.g. corn, onion, gladiolus, oat, wheat and grass). Some strains in subgroups 16SrI-A, 16SrI-B, 16SrI-D, 16SrI-E, 16SrI-F and 16SrI-Q can cause diseases in woody plants (e.g. grey dogwood, sandalwood, blueberry, mulberry, peach, cherry, olive and paulownia).
Symptoms induced in infected plants.
Symptoms can vary, depending on the phytoplasma strain. Typical symptoms of AY (caused by members of subgroup 16SrI-A and 16SrI-B) include virescence (greening of flower petals) and phyllody (development of floral parts into leaf-like structures), flower streaking and malformation, yellowing and upright posture of leaves, elongation and etiolation of internodes, excessive branching of axillary shoots, witches'-broom and general stunting of plants. However, some infected plants may exhibit only some of these symptoms. Symptoms induced by subgroup 16SrI-C phytoplasmas generally include virescence and phyllody, without excessive shoot proliferation. Symptoms induced by members of the other 16SrI subgroups include general stunting (little leaves, small flowers, shortening of internodes), leaf curl or rolling, small and faintly coloured flowers and some symptoms that are typical of the AY syndrome. Plants infected with mild strains may show no obvious symptoms.
Description of ‘Candidatus Phytoplasma asteris’.
We propose that phytoplasma strain OAY (=MIAY) should be assigned as a reference strain to a novel ‘Candidatus’ species to represent the AY group. Based on the guidelines proposed by Murray & Schleifer (1994), the OAY phytoplasma is designated as a novel species with the following description: ‘Candidatus Phytoplasma asteris' [Gr. aster star; common name of the first known host]: [(Mollicutes) NC; NA; O, wall-less; NAS (GenBank accession no. M30790, M74770); oligonucleotide sequences of unique regions of 16S rRNA gene: 5'-GGGAGGA-3' (226–232), 5'-CTGACGGTACC-3' (476–485) and 5'-CACAGTGGAGGTTATCAGTTG-3' (1008–1028); oligonucleotide sequences of unique regions of ribosomal protein genes: rpl22, 5'-CCGCGAACAACTT-3' (218–230) and 5'-AGTAATAACTTCTAGCACAAACTTGC-3' (338–363) and rps3, 5'-AAAGAAGATTTTTTAATTC-3' (114–133) and 5'-CTAGAAAATCGTATG-3' (396–410); P (Oenothera hookeri, phloem); M]. OAY is the reference strain.
|
ACKNOWLEDGEMENTS |
|---|
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTS AND DISCUSSIONREFERENCES |
|---|
Albouy, J. (1966). Le problème des germes fins du gladieul. Ann Epiphyt 17, 81–93 (in French).
Alminaite, A., Davis, R. E., Valiunas, D. & Jomantiene, R. (2002). First report of a group 16SrI, subgroup B, phytoplasma in diseased Epilobium hirsutum in the region of Tallin, Estonia. Plant Dis 86, 1177.[Medline]
Berges, R., Cousin, M.-T., Roux, J., Mäurer, R. & Seemüller, E. (1997). Detection of phytoplasma infections in declining Populus nigra ‘Italica’ trees and molecular differentiation of the aster yellows phytoplasmas identified in various Populus species. Eur J For Pathol 27, 33–43.
Bertaccini, A., Davis, R. E., Lee, I.-M., Conti, M., Dally, E. L. & Douglas, S. M. (1990). Detection of chrysanthemum yellows mycoplasmalike organism by dot hybridization and Southern blot analysis. Plant Dis 74, 40–43.[Medline]
Bertaccini, A., Mittempergher, L. & Vibio, M. (1996). Identification of phytoplasmas associated with a decline of European hackberry (Celtis australis). Ann Appl Biol 128, 245–253.
Bertaccini, A., Carraro, L., Davies, D. L., Laimer da Câmara Machado, M., Martini, M., Paltrinieri, S. & Seemüller, E. (2000). Micropropagation of a collection of phytoplasma strains in periwinkle and other host plants. In Proceedings of the 13th International Congress of IOM, Fukuoka, Japan, July 14–19 2000. Abstract no. 101.
Borth, W. B., Hamasaki, R. T., Ogata, D., Fukuda, S. K. & Hu, J. S. (2002). First report of phytoplasmas infecting watercress in Hawaii. Plant Dis 86, 331.[Medline]
Brcák, J. (1979). Leafhopper and planthopper vectors of plant disease agents in central and southern Europe. In Leafhopper Vectors and Plant Disease Agents, pp. 97–154. Edited by K. Maramorosch & K. F. Harris. New York: Academic Press.
Chiykowski, L. N. (1991). Vector–pathogen–host plant relationships of clover phyllody mycoplasmalike organism and the vector leafhopper Paraphlepsius irroratus. Can J Plant Pathol 13, 11–18.[Medline]
Cousin, M. T., Sharma, J., Rousseau, J., Poitevin, J.-P. & Savoure, A. (1986). Hydrangea virescence. I. Description of the disease and its transmission to the differential host plant Catharanthus roseus by Cuscuta subinclusa. Agron Sci Prod Veg Environ 6, 249–254.[Medline]
Danielli, A., Bertaccini, A., Vibio, M. & Rapetti, S. (1996). Identificazione di fitoplasmi associati allo scopazzo dell' olivo. In Atti Convegno Annuale SIPaV (Società Italiana di Patologia Vegetale), pp. C28–C29. September 26–27 1996, Udine, Italy (in Italian).
Davis, R. E., Lee, I.-M., Douglas, S. M. & Dally, E. L. (1990). Molecular cloning and detection of chromosomal and extrachromosomal DNA of the mycoplasmalike organism (MLO) associated with little leaf disease in periwinkle (Catharanthus roseus). Phytopathology 80, 789–793.
Davis, R. E., Dally, E. L., Gundersen, D. E., Lee, I.-M. & Habili, N. (1997). "Candidatus Phytoplasma australiense," a new phytoplasma taxon associated with Australian grapevine yellows. Int J Syst Bacteriol 47, 262–269.
Deng, S. & Hiruki, C. (1991). Genetic relatedness between two nonculturable mycoplasmalike organisms revealed by nucleic acid hybridization and polymerase chain reaction. Phytopathology 81, 1475–1479.
Faivre-Amiot, A., Moreau, J.-P., Cousin, M.-T. & Staron, T. (1970). Essai de mise en culture de l'agent de la phyllodie du trèfle. Ann Phytopathol 2, 251–258 (in French).[Medline]
Griffiths, H. M., Sinclair, W. A., Davis, R. E., Lee, I.-M., Dally, E. L., Guo, Y.-H., Chen, T. A. & Hibben, C. R. (1994). Characterization of mycoplasmalike organisms from Fraxinus, Syringa, and associated plants from geographically diverse sites. Phytopathology 84, 119–126.
Griffiths, H. M., Sinclair, W. A., Smart, C. D. & Davis, R. E. (1999). The phytoplasma associated with ash yellows and lilac witches'-broom: ‘Candidatus Phytoplasma fraxini’. Int J Syst Bacteriol 49, 1605–1614.
Gundersen, D. E., Lee, I.-M., Rehner, S. A., Davis, R. E. & Kingsbury, D. T. (1994). Phylogeny of mycoplasmalike organisms (phytoplasmas): a basis for their classification. J Bacteriol 176, 5244–5254.
Gundersen, D. E., Lee, I.-M., Schaff, D. A., Harrison, N. A., Chang, C. J., Davis, R. E. & Kingsbury, D. T. (1996). Genomic diversity and differentiation among phytoplasma strains in 16S rRNA groups I (aster yellows and related phytoplasmas) and III (X-disease and related phytoplasmas). Int J Syst Bacteriol 46, 64–75.
Harrison, N. A., Richardson, P. A., Tsai, J. H., Ebbert, M. A. & Kramer, J. B. (1996a). PCR assay for detection of the phytoplasma associated with maize bushy stunt disease. Plant Dis 80, 263–269.
Harrison, N. A., Tsai, J. H. & Richardson, P. A. (1996b). Etiological and epidemiological investigations of periwinkle witches'-broom disease in Florida. IOM Lett 4, 197–198.
IRPCM. (2000). Report of the working team for phytoplasmas, spiroplasmas, mesoplasmas and entomoplasmas. In Report of Consultations of the International Research Program on Comparative Mycoplasmology (IRPCM) of the International Organization for Mycoplasmology (IOM). Fukuoka, Japan: IOM.
Jomantiene, R., Davis, R. E., Maas, J. & Dally, E. L. (1998). Classification of new phytoplasmas associated with diseases of strawberry in Florida, based on analysis of 16S rRNA and ribosomal protein gene operon sequences. Int J Syst Bacteriol 48, 269–277.
Jomantiene, R., Davis, R. E., Antoniuk, L. & Staniulis, J. (2000). First report of phytoplasmas in soybean, alfalfa, and Lupinus sp. in Lithuania. Plant Dis 84, 198.[Medline]
Jomantiene, R., Davis, R. E., Alminaite, A., Valiunas, D. & Jasinskaite, R. (2002a). First report of oat as host of a phytoplasma belonging to group 16SrI, subgroup A. Plant Dis 86, 443.[Medline]
Jomantiene, R., Maas, J. L., Takeda, F. & Davis, R. E. (2002b). Molecular identification and classification of strawberry phylloid fruit phytoplasma in group 16SrI, new subgroup R. Plant Dis 86, 920.[Medline]
Jung, H.-Y., Sawayanagi, T., Kakizawa, S. & 7 other authors (2002). ‘Candidatus Phytoplasma castaneae’, a novel phytoplasma taxon associated with chestnut witches' broom disease. Int J Syst Evol Microbiol 52, 1543–1549.[Abstract]
Keane, G., Edwards, A. & Clark, M. F. (1996). Differentiation of group 16SrI-B aster yellows phytoplasmas with monoclonal antibodies. In BCPC Symposium Proceedings: Diagnostic in Crop Production no. 65, pp. 263–268.
Kunkel, L. O. (1926). Studies on aster yellows. Am J Bot 23, 646–705.[CrossRef]
Kunkel, L. O. (1932). Celery yellows of California not identical with the aster yellows of New York. Contrib Boyce Thompson Inst 4, 405–414.[Medline]
Kuske, C. R. & Kirkpatrick, B. C. (1992). Phylogenetic relationships between the western aster yellows mycoplasmalike organism and other prokaryotes established by 16S rRNA gene sequence. Int J Syst Bacteriol 42, 226–233.
Lee, I.-M. & Davis, R. E. (1988). Detection and investigation of genetic relatedness among aster yellows and other mycoplasma-like organisms by using cloned DNA and RNA probes. Mol Plant–Microbe Interact 1, 303–310.
Lee, I.-M. & Davis, R. E. (2000). Aster yellows. In Encyclopedia of Plant Pathology, pp. 60–63. Edited by O. C. Maloy & T. D. Murray. New York: Wiley.
Lee, I.-M., Davis, R. E., Chen, T.-A., Chiykowski, L. N., Fletcher, J., Hiruki, C. & Schaff, D. A. (1992). A genotype-based system for identification and classification of mycoplasmalike organisms (MLOs) in the aster yellows MLO strain cluster. Phytopathology 82, 977–986.[CrossRef]
Lee, I.-M., Davis, R. E., Sinclair, W. A., DeWitt, N. D. & Conti, M. (1993a). Genetic relatedness of mycoplasmalike organisms detected in Ulmus spp. in the United States and Italy by means of DNA probes and polymerase chain reactions. Phytopathology 83, 829–833.[CrossRef]
Lee, I.-M., Hammond, R. W., Davis, R. E. & Gundersen, D. E. (1993b). Universal amplification and analysis of pathogen 16S rDNA for classification and identification of mycoplasmalike organisms. Phytopathology 83, 834–842.[CrossRef]
Lee, I.-M., Gundersen-Rindal, D. E. & Bertaccini, A. (1998a). Phytoplasma: ecology and genomic diversity. Phytopathology 88, 1359–1366.[Medline]
Lee, I.-M., Gundersen-Rindal, D. E., Davis, R. E. & Bartoszyk, I. M. (1998b). Revised classification scheme of phytoplasmas based on RFLP analyses of 16S rRNA and ribosomal protein gene sequences. Int J Syst Bacteriol 48, 1153–1169.
Lee, I.-M., Davis, R. E. & Gundersen-Rindal, D. E. (2000). Phytoplasma: phytopathogenic mollicutes. Annu Rev Microbiol 54, 221–255.[CrossRef][Medline]
Lee, M. E., Grau, C. R., Lukaesko, L. A. & Lee, I.-M. (2002). Identification of aster yellows phytoplasmas in soybean in Wisconsin based on RFLP analysis of PCR-amplified products (16S rDNAs). Can J Plant Pathol 24, 125–130.[Medline]
Lim, P.-O. & Sears, B. B. (1989). 16S rRNA sequence indicates that plant-pathogenic mycoplasmalike organisms are evolutionarily distinct from animal mycoplasmas. J Bacteriol 171, 5901–5906.
Lim, P.-O. & Sears, B. B. (1992). Evolutionary relationships of a plant-pathogenic mycoplasmalike organism and Acholeplasma laidlawii deduced from two ribosomal protein gene sequences. J Bacteriol 174, 2606–2611.
Lin, C. P. & Chen, T.-A. (1985). Monoclonal antibodies against the aster yellows agent. Science 227, 1233–1235.
Maixner, M., Aherns, U. & Seemüller, E. (1994). Detection of mycoplasmalike organisms associated with a yellows disease of grapevine in Germany. J Phytopathol 142, 1–10.[Medline]
Marcone, C., Ragozzino, A. & Seemüller, E. (1997a). Detection and identification of phytoplasmas in yellows-diseased weeds in Italy. Plant Pathol 46, 530–537.[CrossRef][Medline]
Marcone, C., Ragozzino, A. & Seemüller, E. (1997b). Detection and identification of phytoplasmas infecting vegetable, ornamental and forage crops in southern Italy. J Plant Pathol 79, 211–217.[Medline]
Marcone, C., Ragozzino, A. & Seemüller, E. (1997c). Detection and identification of phytoplasmas infecting wild plant species in southern Italy. In Proceedings of the 10th Congress of the Mediterranean Phytopathology Union, pp. 251–255. Montpellier, 1–5 June 1997.
Marcone, C., Lee, I.-M., Davis, R. E., Ragozzino, A. & Seemüller, E. (2000). Classification of aster yellows-group phytoplasmas based on combined analyses of rRNA and tuf gene sequences. Int J Syst Evol Microbiol 50, 1703–1713.
Marwitz, R. (1990). Diversity of yellows disease agents in plant infections. Zentbl Bakteriol Suppl 20, 431–434.
McCoy, R. E., Caudwell, A., Chang, C. J. & 16 other authors (1989). Plant diseases associated with mycoplasma-like organisms. In The Mycoplasmas, vol. 5, pp. 545–640. Edited by R. F. Whitcomb & J. G. Tully. San Diego, CA: Academic Press.
Montano, H. G., Davis, R. E., Dally, E. L., Hogenhout, S., Pimentel, J. P. & Brioso, P. S. T. (2001). ‘Candidatus Phytoplasma brasiliense’, a new phytoplasma taxon associated with hibiscus witches' broom disease. Int J Syst Evol Microbiol 51, 1109–1118.[Abstract]
Murray, R. G. E. & Schleifer, K. H. (1994). Taxonomic notes: a proposal for recording the properties of putative taxa of procaryotes. Int J Syst Bacteriol 44, 174–176.
Namba, S., Oyaizu, H., Kato, S., Iwanami, S. & Tsuchizaki, T. (1993). Phylogenetic diversity of phytopathogenic mycoplasmalike organisms. Int J Syst Bacteriol 43, 461–467.
Okuda, S., Prince, J. P., Davis, R. E., Dally, E. L., Lee, I.-M., Morgen, B. & Kato, S. (1997). Two groups of phytoplasmas from Japan distinguished on the basis of amplification and restriction analysis of 16S rDNA. Plant Dis 81, 301–305.[CrossRef][Medline]
Sawayanagi, T., Horikoshi, N., Kanehira, T., Shinohara, M., Bertaccini, A., Cousin, M.-T., Hiruki, C. & Namba, S. (1999). ‘Candidatus Phytoplasma japonicum’, a new phytoplasma taxon associated with Japanese Hydrangea phyllody. Int J Syst Bacteriol 49, 1275–1285.
Schneider, B., Ahrens, U., Kirkpatrick, B. C. & Seemüller, E. (1993). Classification of plant-pathogenic mycoplasma-like organisms using restriction-site analysis of PCR-amplified 16S rDNA. J Gen Microbiol 139, 519–527.
Schneider, B., Seemüller, E., Smart, C. D. & Kirkpatrick, B. C. (1995). Phylogenetic classification of plant pathogenic mycoplasma-like organisms or phytoplasmas. In Molecular and Diagnostic Procedures in Mycoplasmology, vol. 1, pp. 369–380. Edited by S. Razin & J. G. Tully. San Diego, CA: Academic Press.
Schneider, B., Marcone, C., Kampmann, M., Ragozzino, A., Lederer, W., Cousin, M.-T. & Seemüller, E. (1997). Characterization and classification of phytoplasmas from wild and cultivated plants by RFLP and sequence analysis of ribosomal DNA. Eur J Plant Pathol 103, 675–686.[CrossRef][Medline]
Sears, B. B., Lim, P.-O., Holland, N., Kirkpatrick, B. C. & Klomparens, K. L. (1989). Isolation and characterization of DNA from a mycoplasmalike organism. Mol Plant–Microbe Interact 2, 175–180.
Seemüller, E., Schneider, B., Mäurer, R. & 8 other authors (1994). Phylogenetic classification of phytopathogenic mollicutes by sequence analysis of 16S ribosomal DNA. Int J Syst Bacteriol 44, 440–446.
Seemüller, E., Marcone, C., Lauer, U., Ragozzino, A. & Göschl, M. (1998). Current status of molecular classification of the phytoplasmas. J Plant Pathol 80, 3–26.
Stanosz, G. R., Heimann, M. F. & Lee, I.-M. (1997). Purple coneflower is a host of the aster yellows phytoplasma. Plant Dis 81, 424.[Medline]
Tsai, J. H. (1979). Vector transmission of mycoplasmal agents of plant diseases. In The Mycoplasmas, vol. 3, pp. 266–307. Edited by R. E. Whitcomb & J. G. Tully. San Diego, CA: Academic Press.
Valiunas, D. (2003). Identification of phytoplasmas in Lithuania and estimation of their biodiversity and molecular evolutionary relationships. PhD thesis, Institute of Botany, Vilnius, Lithuania.
Valiunas, D., Alminaite, A., Staniulis, J., Jomantiene, R. & Davis, R. E. (2001). First report of aster yellows-related subgroup I-A phytoplasma strains in carrot, phlox, sea-lavender, aconitum, and hyacinth in Lithuania. Plant Dis 85, 804.[Medline]
Van Slogteren, D. H. M., Groen, N. P. A. & Muller, P. J. (1974). Yellow disease of gladiolus and hyacinth in the Netherlands. 1. Additional data on field control with systemic insecticides and effects of treating corms and bulbs in hot water. 2. Detection of mycoplasma-like bodies in the phloem of diseased hyacinth leaves. Acta Hortic 36, 303–311.
Verdin, E., Salar, P., Danet, J.-L., Choueiri, E., Jreijiri, F., El Zammar, S., Gélie, B., Bové, J. M. & Garnier, M. (2003). ‘Candidatus Phytoplasma phoenicium’, a novel phytoplasma associated with an emerging lethal disease of almond trees in Lebanon and Iran. Int J Syst Evol Microbiol 53, 833–838.
Vibio, M., Bertaccini, A., Lee, I.-M., Davis, R. E., Minucci, C. & Milne, R. G. (1994). Etiology of lettuce yellows in Italy: genetic characterization of associated mycoplasmalike organisms. Phytopathol Mediterr 33, 179–186.[Medline]
Vibio, M., Bertaccini, A., Schiliro, E. & Rapetti, S. (1995). Caratterizzazione molecolare di fitoplasmi associati a virescenza in anemone. Informatore Fitopatologico 45, 60–62 (in Italian).[Medline]
Vibio, M., Bertaccini, A., Lee, I.-M., Davis, R. E. & Clark, M. F. (1996). Differentiation and classification of aster yellows and related European phytoplasmas. Phytopathol Mediterr 35, 33–42.[Medline]
Villalobos, W., Moreira, L., Rivera, C., Bottner, K. D. & Lee, I.-M. (2002). First report of an aster yellows subgroup 16SrI-B phytoplasma infecting chayote in Costa Rica. Plant Dis 86, 330.
Wang, K. & Hiruki, C. (2001). Molecular characterization and classification of phytoplasmas associated with canola yellows and a new phytoplasma strain associated with dandelions. Plant Dis 85, 76–79.[Medline]
White, D. T., Blackall, L. L., Scott, P. T. & Walsh, K. B. (1998). Phylogenetic positions of phytoplasmas associated with dieback, yellow crinkle and mosaic diseases of papaya, and their proposed inclusion in ‘Candidatus Phytoplasma australiense’ and a new taxon, ‘Candidatus Phytoplasma australasia’. Int J Syst Bacteriol 48, 941–951.
Zreik, L., Carle, P., Bové, J. M. & Garnier, M. (1995). Characterization of the mycoplasmalike organism associated with witches'-broom disease of lime and proposition of a "Candidatus" taxon for the organism, "Candidatus Phytoplasma aurantifolia". Int J Syst Bacteriol 45, 449–453.
This article has been cited by other articles:
|
|
 |
|
  W. Wei, I.-M. Lee, R. E. Davis, X. Suo, and Y. Zhao Automated RFLP pattern comparison and similarity coefficient calculation for rapid delineation of new and distinct phytoplasma 16Sr subgroup lineages Int J Syst Evol Microbiol, October 1, 2008; 58(10): 2368 - 2377. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Malembic-Maher, F. Constable, A. Cimerman, G. Arnaud, P. Carle, X. Foissac, and E. Boudon-Padieu A chromosome map of the Flavescence doree phytoplasma Microbiology, May 1, 2008; 154(5): 1454 - 1463. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Martini, I.-M. Lee, K. D. Bottner, Y. Zhao, S. Botti, A. Bertaccini, N. A. Harrison, L. Carraro, C. Marcone, A. J. Khan, et al. Ribosomal protein gene-based phylogeny for finer differentiation and classification of phytoplasmas Int J Syst Evol Microbiol, September 1, 2007; 57(9): 2037 - 2051. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Arocha, O. Antesana, E. Montellano, P. Franco, G. Plata, and P. Jones 'Candidatus Phytoplasma lycopersici', a phytoplasma associated with 'hoja de perejil' disease in Bolivia Int J Syst Evol Microbiol, August 1, 2007; 57(8): 1704 - 1710. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Wei, R. E. Davis, I.-M. Lee, and Y. Zhao Computer-simulated RFLP analysis of 16S rRNA genes: identification of ten new phytoplasma groups Int J Syst Evol Microbiol, August 1, 2007; 57(8): 1855 - 1867. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Cimerman, G. Arnaud, and X. Foissac Stolbur phytoplasma genome survey achieved using a suppression subtractive hybridization approach with high specificity. Appl. Envir. Microbiol., May 1, 2006; 72(5): 3274 - 3283. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Bai, J. Zhang, A. Ewing, S. A. Miller, A. Jancso Radek, D. V. Shevchenko, K. Tsukerman, T. Walunas, A. Lapidus, J. W. Campbell, et al. Living with genome instability: the adaptation of phytoplasmas to diverse environments of their insect and plant hosts. J. Bacteriol., May 1, 2006; 188(10): 3682 - 3696. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Valiunas, J. Staniulis, and R. E. Davis 'Candidatus Phytoplasma fragariae', a novel phytoplasma taxon discovered in yellows diseased strawberry, Fragariaxananassa Int J Syst Evol Microbiol, January 1, 2006; 56(1): 277 - 281. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Arocha, M. Lopez, B. Pinol, M. Fernandez, B. Picornell, R. Almeida, I. Palenzuela, M. R. Wilson, and P. Jones 'Candidatus Phytoplasma graminis' and 'Candidatus Phytoplasma caricae', two novel phytoplasmas associated with diseases of sugarcane, weeds and papaya in Cuba Int J Syst Evol Microbiol, November 1, 2005; 55(6): 2451 - 2463. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
The IRPCM Phytoplasma/Spiroplasma Working Team - P 'Candidatus Phytoplasma', a taxon for the wall-less, non-helical prokaryotes that colonize plant phloem and insects Int J Syst Evol Microbiol, July 1, 2004; 54(4): 1243 - 1255. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
X174 RFI DNA HaeIII digest [fragment sizes (bp) from top to bottom for 5 % gel: 1353, 1078, 872, 603, 310, 281, 271, 234, 194, 118, 72; fragment sizes (bp) from top to bottom for 12 % gel: 1078, 872, 603, 310, 281, 271, 234, 194, 118, 72]. Other abbreviations are defined in Table 1