First Report of “Candidatus Phytoplasma asteris”-Related Strains in Brassica rapa in Saskatchewan, Canada

“Candidatus phytoplasma asteris” and related strains (i.e., aster yellows group 16SrI) have been associated with diseases of numerous plant species worldwide. Symptoms of aster yellows (AY) have been reported on rapeseed/canola (Brassica napus and B. rapa) crops in Saskatchewan (SK) and Manitoba, Canada since 1953 (2). Symptoms generally include stunting, virescence, leaf yellowing or purpling, phyllody, and formation of bladder-like siliques. A total of 120 mature B. rapa cv. AC Sunbeam plants exhibiting AY symptoms were collected in commercial fields near Medstead, SK during 2003 and 2004 (one field per year). As described previously (4), total genomic DNA was extracted from leaf, stem, roots, and seeds collected from the 120 plants, from seeds from the seed lots sown in 2003 and 2004, and from leaf and stem tissue of 20 greenhouse-grown plants from each seed lot. The latter DNA samples were assayed for phytoplasma DNA by a nested polymerase chain reaction (PCR) assay incorporating phytoplasma universal 16S rRNA primer pairs P1/P6 (1) followed by R16R2/R16F2 (4). Seed samples analyzed from the 2003 and 2004 seed lots and tissues of the 40 greenhouse-grown plants all tested negative for phytoplasma DNA using this assay. Leaf, stem, and/or root tissues of all plants collected in the field in 2003 (60 plants) and 2004 (60 plants) and 71.1% (315 of 443) of seed samples (five seeds per sample) tested positive for the presence of phytoplasma DNA, as evidenced by the presence of an expected band of 1.2 kb on the gels after the second amplification with primers R16R2/R16F2. Nested PCR products from plant samples collected in 2003 were cloned, sequenced, and compared with phytoplasma sequences archived in the GenBank nucleotide database. On this basis, phytoplasmas detected in plants or their seeds collected in 2003 were found to be most similar (98.8%) to CHRY (Accession No. AY180956), a 16SrI-A subgroup strain, or were most similar (98.9%) to isolate 99UW89 (Accession no. AF268407), a known 16SrI-B subgroup strain. Sequences of phytoplasmas detected in plants or their seeds in 2004 were obtained by direct sequencing of rRNA products amplified from samples using PCR incorporating primer pairs P1/P6 and P4/P7 (3). Analysis of sequence data revealed that phytoplasmas in these plants were all most similar (99.5%) to AY-WB (Accession no. AY389828), a 16SrI-A subgroup member. The nucleotide sequences have been deposited with GenBank under Accession nos. DQ404346, DQ404347, and DQ411470. To our knowledge, this is the first report of 16SrI-A and 16SrI-B subgroup phytoplasmas infecting plants and seed of B. rapa in Saskatchewan. References: (1) I.-M. Lee et al. Phytopathology, 83:834, 1993. (2) W. E. Sackston. Can. Plant Dis. Surv. 33:41, 1953. (3) L. B. Sharmila et al. J. Plant Biochem. Biotech. 13:1, 2004. (4) E. Tanne et al. Phytopathology, 91:741, 2001.

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Molecular characterisation of phytoplasmas infecting roses in Poland

Acta Agrobotanica ◽

10.5586/aa.2002.031 ◽

2013 ◽

Vol 55 (1) ◽

pp. 325-334

Author(s):

Hanna Śliwa ◽

Tadeusz Malinowski ◽

Maria Kamińska

Keyword(s):

Reference Strain ◽

Fragment Length Polymorphism ◽

Rflp Analysis ◽

Nested Polymerase Chain Reaction ◽

Aster Yellows ◽

Leaf Chlorosis ◽

Leaf Yellowing ◽

Pcr Products ◽

Polymerase Chain ◽

Aster Yellows Phytoplasma

Symptoms of shoot dieback and leaf yellowing followed by leaf chlorosis were observed in naturally infected roses 'Frisco' and 'Suela', cultivated in a commercial greenhouse in Poland. The presence of phytoplasma was demonstrated in affected plants by nested polymerase chain reaction (PCR) with R16Fl/RO and Pl/P7 primer pairs in the first round followed by a second one with R16F2n/R2, fA/rA, Pc399/P1694, R16(I)Fl/Rl and Pl/fArev primer pairs. Restriction fragment length polymorphism (RFLP) analysis of PCR products (primed with primers R16F2n/R2) was done using enzymes AluI, MseI, RsaI and HpaII. Restriction profiles obtained with these enzymes were identical to those of reference strain AY1 belonging to aster yellows phytoplasma group, subgroup I-B (16SrI-B). Nested PCR products from roses 'Frisco' and 'Suela' were sequenced. Analysis of sequences confirmed that the phytoplasma infecting those roses could be classified to aster yellows phytoplasma group, subgroup B.

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First Report of Aster Yellows (16SrI-B) Associated with Potatoes in Alaska

Plant Disease ◽

10.1094/pdis-12-10-0913 ◽

2011 ◽

Vol 95 (6) ◽

pp. 767-767

Author(s):

J. H. McBeath ◽

P. J. Laski ◽

M. Cheng

Keyword(s):

Nested Pcr ◽

Disease Transmission ◽

Sequence Data ◽

Restriction Enzymes ◽

Reference Pattern ◽

Aster Yellows ◽

First Report ◽

Group I ◽

Pcr Product ◽

Pcr Products

During a disease survey conducted in 2009 in Alaska, one potato plant (Solanum tuberosum) with symptoms characteristic of aster yellows, such as apical leaves rolling inward, leaves turning yellow or purple, and presence of aerial tubers, was found in a commercial field. Total DNA was extracted from leaves, stems, and roots of the symptomatic and symptomless plants with a DNeasy Plant Mini Kit (Qiagen, Valencia, CA) according to the instructions of the manufacturer. A nested PCR was carried out with the first round primer pair P1/P7 followed by second round primer pair R16F2n/R16R2 (1,3). An approximate 1.2-kb PCR product was amplified from the symptomatic plant, but not symptomless plants. The PCR products from R16F2n/R16R2 were digested using restriction enzymes AluI, BfaI, BstUI, HhaI, HpaI, KpnI, MseI, and RsaI. The restriction fragment length polymorphism (RFLP) patterns were compared with those from known phytoplasma strains (1) and they matched the patterns for aster yellows subgroup B (16SrI-B). After P1/P7 amplification, the nested PCR product of primer pair P1A/16S-SR (2) was purified with a MiniElute Gel Extraction kit (Qiagen), sequenced by GENEWIZ (South Plainfield, NJ), and the sequence data analyzed by iPhyClassifier software (4). The results indicated that the sequence (GenBank Accession No. HQ599231) had 99.65% similarity to ‘Candidatus Phytoplasma asteris’ reference strain (GenBank Accession No. M30790). The RFLP similarity was identical (coefficient 1.00) to the reference pattern of 16Sr group I, subgroup B (GenBank Accession No. NC 005303). To our knowledge, this is the first report on the molecular identification of aster yellows phytoplasma associated with potatoes in Alaska. The source of the phytoplasma and pathway of disease transmission is currently under investigation. References: (1) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) I.-M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:337, 2004. (3) C. D. Smart et al. Appl. Environ. Microbiol. 62:2988, 1996. (4) Y. Zhao et al. Int. J. Syst. Evol. Microbiol. 59:2582, 2009.

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First Report of Virus and Phytoplasma Pathogens Associated with Yellow Leaf Syndrome of Sugarcane in Cuba

Plant Disease ◽

10.1094/pdis.1999.83.12.1177b ◽

1999 ◽

Vol 83 (12) ◽

pp. 1177-1177 ◽

Cited By ~ 28

Author(s):

Y. Arocha ◽

L. Gonzalez ◽

E. L. Peralta ◽

P. Jones

Keyword(s):

Enzyme Linked Immunosorbent Assay ◽

Local Alignment ◽

Polymorphism Analysis ◽

Yellow Leaf ◽

Nested Polymerase Chain Reaction ◽

Aster Yellows ◽

First Report ◽

Pcr Products ◽

Search Tool ◽

Saccharum Sp

Yellow leaf syndrome (YLS) has been seen recently in sugarcane (Saccharum sp.) in Cuba. The primary symptom is a yellow discoloration of the midrib that may spread from the midrib to the lamina in cane 6 months and older. In certain cultivars, such as CP 5243, EPC 17-395, and F31-156, a reddish coloration has been observed. In severe cases, plants are stunted and can be pulled easily. YLS was first reported from Hawaii, followed by Brazil, Florida, and Australia, where it is associated with a luteovirus: sugarcane yellow leaf virus (ScYLV). However, in South Africa, YLS is associated with a phytoplasma: sugarcane yellow leaf phytoplasma (ScYLP) (1). A survey performed in Jovellanos, Matanzas, Cuba, for ScYLV, using enzyme-linked immunosorbent assay with antiserum provided by B. E. L. Lockhart, showed that only a small percentage of canes with YLS carried the virus. A nested polymerase chain reaction (PCR) (1) was used to amplify phytoplasma 16S/23S rDNA from sugarcane leaves with YLS symptoms, also collected from Jovellanos. Restriction fragment length polymorphism analysis with HaeIII, RsaI, and AluI produced patterns similar to those of members of the aster yellows group for 260 of 277 samples tested. Sequencing of the 16S/23S intergenic rDNA PCR products, followed by BLAST (basic local alignment search tool) analysis, confirmed the high homology (97%) of these amplimers to the DNA of phytoplasmas belonging to the aster yellows I-A subgroup. This is the first report of ScYLV and ScYLP from Cuba, and it demonstrates the difficulty of determining the identity of the YLS pathogen based on symptoms alone. Reference: (1) C. P. R. Cronjé et al. Ann. Appl. Biol. 133:177, 1998.

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First Report of an Aster Yellows Subgroup 16SrI-B Phytoplasma Infecting Chayote in Costa Rica

Plant Disease ◽

10.1094/pdis.2002.86.3.330c ◽

2002 ◽

Vol 86 (3) ◽

pp. 330-330 ◽

Cited By ~ 3

Author(s):

W. Villalobos ◽

L. Moreira ◽

C. Rivera ◽

K. D. Bottner ◽

I.-M. Lee

Keyword(s):

Costa Rica ◽

Rflp Analysis ◽

Restriction Enzymes ◽

Potential Threat ◽

Nested Polymerase Chain Reaction ◽

Aster Yellows ◽

First Report ◽

Rdna Sequences ◽

Pcr Products ◽

Production Area

An outbreak of a witches' broom disease affected approximately 20% of plants in several chayote (Sechium edule (Jacq.) Schwartz) fields in the commercial production area of the Ujarrás Valley, Cartago Province, Costa Rica during 2000 and 2001. Affected chayote plants exhibited symptoms, including basal proliferation with severe foliage reduction, aborted flowers, and deformed fruits, suggestive of phytoplasmal infection. Two other symptomatic cucurbit species growing near the chayote fields were also identified. These species were tacaco plants (S. tacaco (Pitt.) C. Jeffrey), an edible cucurbit for domestic marketing in Costa Rica, showing severe size reduction of leaves and fruits, and Rytidostylis carthaginensis (Jacq.) Kuntze, a weed in chayote and tacaco fields, exhibiting abnormal tendril proliferation. Plants were analyzed for phytoplasma infection by a nested polymerase chain reaction (PCR) assay, using the universal rRNA primer pair P1/P7 followed by R16F2n/R16R2 (2). Phytoplasmas were detected in all symptomatic samples (18 chayote, 6 tacaco, and 3 weed) tested but were undetectable in all asymptomatic samples (10 chayote, 6 tacaco, and 2 weed). Restriction fragment length polymorphism (RFLP) analysis of PCR products (16S rDNA sequences) by separate digestion with eight restriction enzymes (RsaI, HhaI, KpnI, BfaI, HaeIII, HpaII, AluI, MseI) revealed that a phytoplasma belonging to subgroup 16SrI-B in the aster yellows phytoplasma group (16SrI) was associated with chayote witches' broom (CWB). The same or very similar phytoplasmas were found in both symptomatic tacaco and R. carthaginensis plants. Phylogenetic analysis of 16SrDNA sequences also confirmed the CWB phytoplasma to be most similar to members of subgroup 16SrI-B. Similar diseases in chayote and other cucurbits have been reported in Brazil (3), Taiwan (1), and Mexico (4). The CWB phytoplasma differs from the phytoplasma (16SrIII-J subgroup) associated with chayote in Brazil. The identities of phytoplasmas associated with cucurbits in Taiwan and Mexico are unknown. The occurrence of an aster yellows group phytoplasma in chayote may pose a potential threat to continued production and exportation of this cash crop. To our knowledge, this is the first report of 16SrI-B subgroup phytoplasmas in naturally infected cucurbits in Costa Rica. References: (1) T. G. Chou et al. Plant Dis. Rep. 60:378, 1976. (2) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (3) H. G. Montano et al. Plant Dis. 84:429, 2000. (4) E. Olivas. Rev. Fitopatol. (Lima) 13:14, 1978.

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‘Candidatus Phytoplasma asteris’ Strains Associated with Oil Palm Lethal Wilt in Colombia

Plant Disease ◽

10.1094/pdis-12-12-1182-re ◽

2014 ◽

Vol 98 (3) ◽

pp. 311-318 ◽

Cited By ~ 20

Author(s):

Elizabeth Alvarez ◽

Juan F. Mejía ◽

Nicoletta Contaldo ◽

Samanta Paltrinieri ◽

Bojan Duduk ◽

...

Keyword(s):

Oil Palm ◽

Sequence Data ◽

Severe Disease ◽

Rflp Analysis ◽

Nested Polymerase Chain Reaction ◽

Aster Yellows ◽

Rdna Sequences ◽

Polymerase Chain ◽

Reference Strains

The distribution of lethal wilt, a severe disease of oil palm, is spreading throughout South America. An incidence of about 30% was recorded in four commercial fields in Colombia. In this study, phytoplasmas were detected in symptomatic oil palm by using specific primers, based on 16S ribosomal DNA (rDNA) sequences, in nested polymerase chain reaction assays. The phytoplasmas were then identified as ‘Candidatus Phytoplasma asteris’, ribosomal subgroup 16SrI-B, through the use of restriction fragment length polymorphism (RFLP) analysis and sequencing. Cloning and sequencing of 16S rDNA from selected strains, together with phylogenetic analysis, confirmed the classification. Moreover, collective RFLP characterization of the groEL, amp, and rp genes, together with sequence data, distinguished the aster yellows strain detected in Colombian oil-palm samples from other aster yellows phytoplasmas used as reference strains; in particular, from an aster yellows strain infecting corn in the same country.

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First Report of Alfalfa Witches Broom Disease in Oman Caused by a Phytoplasma of the 16Sr II Group

Plant Disease ◽

10.1094/pdis.2001.85.12.1287a ◽

2001 ◽

Vol 85 (12) ◽

pp. 1287-1287 ◽

Cited By ~ 8

Author(s):

A. J. Khan ◽

K. M. Azam ◽

M. L. Deadman ◽

A. M. Al-Subhi ◽

P. Jones

Keyword(s):

Sweet Potato ◽

Infected Plant ◽

Rflp Analysis ◽

Negative Control ◽

Sultanate Of Oman ◽

Nested Polymerase Chain Reaction ◽

Aster Yellows ◽

First Report ◽

Pcr Products ◽

Plant Pathol

Alfalfa (Medicago sativa L.) is a primary forage crop in the Sultanate of Oman. A new disease of alfalfa in Oman is characterized by proliferation of shoots and yellowing of leaves in 1- to 2-year-old plants and tillering of stems in 4- to 5-year-old plants. Annual losses due to this disease are estimated at more than US$ 23 million. Samples of healthy and infected alfalfa plants were collected from different regions. Total DNA was extracted according to Khadhair et al. (1), with minor modifications. Amplification of 16S rDNA was done using a nested polymerase chain reaction (PCR) approach with primers P1/P7 and R16F2n/R16R2. DNA from healthy leaves and sterile water was used as a negative control, while DNA from periwinkle infected with faba bean phyllody (16SrII-C), aster yellows (16SrI), tomato big bud (16SrII-D), sweet potato little leaf (16SrII-D), catharanthus phyllody (16SrVI), and sesame phyllody (16SrII-A) were used as positive controls and for restriction fragment length polymorphism (RFLP) comparisons. Nested 1.25-kb PCR products from infected plant samples were subjected to RFLP analysis with restriction endonucleases RsaI, AluI, HaeIII, HhaI, EcoRI, TaqI, Tru9I, and Sau3AI. The analysis showed that the alfalfa witches' broom phytoplasma (AWBP) belonged to the 16SrII group (peanut witches' broom) and that the AWBP was most similar to sweet potato little leaf (16SrII-D) but distinct from “Candidatus Phytoplasma aurantifolia,” the cause of lime witches' broom in Oman. Other phytoplasmas infecting alfalfa have been reported from Europe and North America (1,3), but they belong to the 16SrVI (clover phyllody) and 16SrI (aster yellows) groups. An alfalfa witches' broom reported from Italy (2) forms a separate grouping (4). To our knowledge, this is the first report of a phytoplasma from the peanut witches' broom group infecting alfalfa in the Sultanate of Oman. References: (1) A. H. Khadhair et al. Microbiol. Res. 152:259, 1997. (2) C. Marcone et al. J. Plant Pathol. 79:211, 1997. (3) R. D. Peters et al. Plant Dis. 83:488, 1999. (4) E. Seemuller et al. J. Plant Pathol. 80:3, 1998.

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First Report of a Group 16SrII Phytoplasma Infecting Chickpea in Oman

Plant Disease ◽

10.1094/pd-90-0973c ◽

2006 ◽

Vol 90 (7) ◽

pp. 973-973 ◽

Cited By ~ 8

Author(s):

N. A. Al-Saady ◽

A. M. Al-Subhi ◽

A. Al-Nabhani ◽

A. J. Khan

Keyword(s):

Nested Pcr ◽

Animal Feed ◽

Restriction Enzymes ◽

Universal Primers ◽

Polymorphism Analysis ◽

Disease Symptoms ◽

First Report ◽

Pcr Products ◽

Polymerase Chain ◽

Group 2

Chickpea (Cicer arietinum), locally known as “Dungo”, is grown for legume and animal feed mainly in the interior region of Oman. During February 2006, survey samples of chickpea leaves from plants showing yellows disease symptoms that included phyllody and little leaf were collected from the Nizwa Region (175 km south of Muscat). Total nucleic acid was extracted from asymptomatic and symptomatic chickpea leaves using a cetyltrimethylammoniumbromide method with modifications (3). All leaf samples from eight symptomatic plants consistently tested positive using a polymerase chain reaction assay (PCR) with phytoplasma universal primers (P1/P7) that amplify a 1.8-kb phytoplasma rDNA product and followed by nested PCR with R16F2n/R16R2 primers yielding a product of 1.2 kb (2). No PCR products were evident when DNA extracted from healthy plants was used as template. Restriction fragment length polymorphism analysis of nested PCR products by separate digestion with Tru9I, HaeIII, HpaII, AluI, TaqI, HhaI, and RsaI restriction enzymes revealed that a phytoplasma belonging to group 16SrII peanut witches'-broom group (2) was associated with chickpea phyllody and little leaf disease in Oman. Restriction profiles of chickpea phytoplasma were identical with those of alfalfa witches'-broom phytoplasma, a known subgroup 16SrII-B strain (3). To our knowledge, this is the first report of phytoplasma infecting chickpea crops in Oman. References: (1) A. J. Khan et al. Phytopathology, 92:1038, 2002. (2). I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998 (3) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA. 81:8014, 1984.

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First Report of an Aster Yellows Phytoplasma Associated with Cabbage in Southern Texas

Plant Disease ◽

10.1094/pdis.2001.85.4.447b ◽

2001 ◽

Vol 85 (4) ◽

pp. 447-447 ◽

Cited By ~ 6

Author(s):

I.-M. Lee ◽

R. A. Dane ◽

M. C. Black ◽

Noel Troxclair

Keyword(s):

16S Rdna ◽

Nested Pcr ◽

Restriction Enzymes ◽

Diagnostic Procedures ◽

Acid Extraction ◽

Insect Vector ◽

Aster Yellows ◽

First Report ◽

Pcr Products ◽

Aster Yellows Phytoplasma

In early spring 2000 carrot crops in southwestern Texas were severely infected by an outbreak of phyllody associated with aster yellows phytoplasma. Cabbage crops that had been planted adjacent to these carrot fields began to display previously unobserved symptoms characteristic of phytoplasma infection. Symptoms included purple discoloration in leaf veins and at the outer edges of leaves on cabbage heads. Proliferation of sprouts also occurred at the base of the stem and between leaf layers of some plants, and sprouts sometimes continued to proliferate on extended stems. About 5% of cabbage plants in the field exhibited these symptoms. Two symptomless and four symptomatic cabbage heads were collected in early April from one cabbage field. Veinal tissues were stripped from each sample and used for total nucleic acid extraction. To obtain specific and sufficient amount of PCR products for analysis, nested PCR was performed by using primer pairs (first with P1/P7 followed by R16F2n/R16R2) (1,2) universal for phytoplasma detection. A specific 16S rDNA fragment (about 1.2 kb) was strongly amplified from the four symptomatic but not from the two asymptomatic samples. The nested PCR products obtained from the four symptomatic samples were then analyzed by restriction fragment length polymorphism (RFLP) using the restriction enzymes MseI, HhaI, and HpaII, and the RFLP patterns were compared to the published patterns of known phytoplasmas (1). The resulting RFLP patterns were identical to those of a phytoplasma belonging to subgroup B of the aster yellows phytoplasma group (16SrI). These RFLP patterns were also evident in putative restriction sites observed in a 1.5 kbp nucleotide sequence of the 16S rDNA. This is the first report of aster yellows phytoplasma associated disease symptoms in cabbage in Texas. The occurrence of cabbage proliferation coincided with the presence of high populations of the insect vector, aster leafhopper. References: (1) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) B. Schneider et al. 1995. Molecular and Diagnostic Procedures in Mycoplasmology, Vol. I. Academic Press, San Diego, CA.

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Cloning of GRK2 cDNA from S49 murine lymphoma cells

AJP Cell Physiology ◽

10.1152/ajpcell.1996.270.3.c885 ◽

1996 ◽

Vol 270 (3) ◽

pp. C885-C891 ◽

Cited By ~ 5

Author(s):

R. J. Hughes ◽

K. L. Anderson ◽

D. Kiel ◽

P. A. Insel

Keyword(s):

Adrenergic Receptor ◽

Direct Sequencing ◽

Single Step ◽

Receptor Kinase ◽

Rt Pcr ◽

Lymphoma Cells ◽

Mouse Lymphoma Cells ◽

Pcr Products ◽

Polymerase Chain ◽

Mouse Lymphoma

Beta-adrenergic receptor kinase is a member of the G protein-linked receptor kinase (GRK1) family that elicits receptor desensitization. We have cloned GRK2 from S49 mouse lymphoma cells. The nucleotide sequences of rat GRK2 and GRK3 were aligned and conserved primers chosen for use in reverse transcription-polymerase chain reaction (RT-PCR) of S49 mRNA. Direct sequencing of the PCR fragment provided a rapid means to identify the expression of the GRK2 but not the GRK3 transcript in these cells. Unique expression of GRK2 in S49 cells was confirmed by Western blotting. Three additional pairs of primers were chosen from the rat GRK2 sequence to amplify overlapping regions that together encompassed the entire coding sequence. After attempts to ligate the four fragments of S49 cell GRK2 cDNA by using PCR proved unsuccessful, the intact cDNA was assembled by digesting the PCR products in the region of the overlaps and ligating them in a single step into pBlue-script SK(+).

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Occurrence of a 16SrIV Group Phytoplasma not Previously Associated with Palm Species in Yucatan, Mexico

Plant Disease ◽

10.1094/pdis-02-10-0150 ◽

2011 ◽

Vol 95 (3) ◽

pp. 256-262 ◽

Cited By ~ 24

Author(s):

Roberto Vázquez-Euán ◽

Nigel Harrison ◽

María Narvaez ◽

Carlos Oropeza

Keyword(s):

Cocos Nucifera ◽

Restriction Enzymes ◽

Nested Polymerase Chain Reaction ◽

Palm Trees ◽

Palm Species ◽

Leaf Yellowing ◽

Sabal Mexicana ◽

Polymerase Chain ◽

First Time

The occurrence of 16SrIV group phytoplasmas in palm species Sabal mexicana and Pseudophoenix sargentii is reported here for the first time. Palm trees showed leaf decay and leaf yellowing syndromes, respectively. An amplification product (1.4 kb) was obtained in symptomatic S. mexicana (18 of 21) and symptomatic P. sargentii (1 of 1) palm trees sampled in different locations in Yucatan State, Mexico; five of the positive S. mexicana and the positive P. sargentii trees died. The identity of the phytoplasmas from these species was determined by restriction fragment length polymorphism profiling with restriction enzymes AluI and HinfI, showing there could be two phytoplasma strains of the 16SrIV group. In one S. mexicana palm, the profile was the same as observed with these enzymes for phytoplasmas of 16SrIV-A subgroup, previously associated with Cocos nucifera palm trees and, in the rest of the trees, including the P. sargentii palm, the profile was for phytoplasmas of the 16SrIV-D subgroup. These identities were supported by analyses of the amplicons obtained by nested polymerase chain reaction by nucleotide-nucleotide BLAST analysis. Geographical distribution of the association S. mexicana/16SrIV group phytoplasmas was found widely dispersed in Yucatan State. A potential role of S. mexicana palm trees as a permanent source of phytoplasma inoculum is suggested. In addition to P. sargentii, other palm species (Thrinax radiata and C. nucifera) coexisting with S. mexicana trees were also sampled and analyzed.

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