Phytoplasma Fraxini Research Articles

The complete genome of "Candidatus Phytoplasma fraxini" AshY1 from the ash yellows group.

The complete genome of "Candidatus Phytoplasma fraxini" AshY1, originating from Fraxinus americana in North America, was assembled using long reads from single-molecule real-time sequencing technology. The chromosome of 598 kb provides insights into the effector repertoire of a phytopathogenic bacterium from the 16SrVII phytoplasma group.

Insects as potential vectors of phytoplasmas in urban trees in a mega-city: a case study in Bogotá, Colombia

Urban trees offer many ecosystem services which can be affected by pathogens, including phytoplasmas. Phytoplasmas cause regulator growth imbalances in infected plants, which produce deviations from the normal plant architecture, among other symptoms. In Bogotá, Colombia, ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma fraxini’ infect at least 11 species of urban trees, including Andean oak. This tree species is endemic to Colombia and Panama, and it plays an important ecologic role in the Colombian Andes wild forests. In Bogotá, knowledge about the insect vectors associated with the transmission of phytoplasmas to Andean oak is scarce. In this work we sampled the entomofauna of Andean oaks and evaluated the role of Cicadellidae and Psylloidea taxa as potential vectors of phytoplasmas in Bogotá. Insects were captured using direct and indirect sampling methods from Andean oaks at three contrasting sites in Bogotá, and also from neighbouring trees. The insects were identified by morphological and molecular methods and tested for phytoplasmas. In total, 510 Cicadellidae members of 13 taxa and 129 Psylloidea of 8 taxa were captured; richness and abundance depended on the type and sampling site. The most abundant species were Scaphytopius (Convelinus) sp. (Cicadellidae) and Acizzia uncatoides (Psylloidea). Leafhoppers positive for phytoplasmas were Chiasmodolini, Dikrella (Readionia) sp., Empoasca sp. and Scaphytopius sp. taxa. Our results suggest that several potential species of phytoplasmas may be dispersing phytoplasmas to Andean oaks and other urban tree species. It is necessary to conduct transmission tests to evaluate the transmission capacity of the potential vectors.

Simultaneous detection and quantification by multiplex qPCR of 'Candidatus Phytoplasma asteris' and 'Candidatus Phytoplasma fraxini' in a plant host and insect vectors

AbstractPhytoplasmas are bacteria transmitted by insects that can cause plant diseases. In Bogotá 'Candidatus Phytoplasma asteris' and ' Candidatus Phytoplasma fraxini', infect 11 species of urban trees, weeds, grass, potato and strawberry. A set of primers, that amplify both phytoplasmas species were designed and used for absolute and relative qPCR quantification of the 16SrRNA gene. The primers AJ-16Sr-F/AJ-16Sr-R allowed the amplification of ‘Ca. P. asteris’, ‘Candidatus Phytoplasma palmae’, ‘Ca. P. fraxini’ and ‘Candidatus Phytoplasma phoenicium’, not of ‘Candidatus Phytoplasma pruni’. Absolute qPCR detected phytoplasmas between 1 × 109 and 1 × 103 copies/μL DNA extract. Two species-specific hydrolysis probes, AJ-16SrI-Cy5.5 and AJ-16SrVII-TexRed, were designed to detect 'Ca. P. asteris' and 'Ca. P. fraxini' respectively, using the AJ-16Sr-F/AJ-16Sr-R primers. For relative quantification, the 18SrRNA gene was used as normalizer. Relative qPCR detected phytoplasmas between 1 × 109 and 1 × 103 copies/μL DNA extract. Multiplex reactions allowed the specific quantification of 'Ca. P. asteris', 'Ca. P. fraxini' in comparison to the normalizer. qPCR methods were validated on natural hosts Andean oak trees and leafhoppers. The relative quantification values were higher for 'Ca. P. fraxini' (x̅ RQ = 3203.1 ± 2622,9 n = 14) compared with 'Ca. P. asteris' (x̅ RQ = 14.9 ± 24,5 n = 6) in oak tree samples. In the leafhoppers, the relative quantification values ranged between RQ = 26.5 and RQ = 294,927.3 for 'Ca. P. fraxini’ and RQ = 34.8 and RQ = 1722.2 for 'Ca. P. asteris'. In conclusion, although absolute qPCR allowed the quantification of phytoplasmas by comparing Cq (quantification cycle) values of samples with a standard curve, it did not allow to differentiate between 'Ca. P. asteris' and 'Ca. P. fraxini'. In contrast, relative qPCR assays using specific hydrolysis probes allowed the specific detection and quantification of each phytoplasma, in individual and mixed infections in insect vectors and plant hosts.

Association of phytoplasmas with a new disease of potato crops in cundinamarca, Colombia

Cundinamarca is the major potato producer region in Colombia. Potato growers first reported the presence of new symptoms affecting commercial potato fields in Cundinamarca as far back as 2012. These included foliage yellowing, curling on the upper leaf side and purple margins, occasionally with purple coloration of the underside veins, excessive shoot proliferation, abnormally short or long internodes and abnormal leaf development. Plants had a distorted pattern of growth suggesting a possible phytoplasma cause. Phytoplasmas were detected by nested PCR of the phytoplasma 16S rRNA gene and we confirmed the presence of ‘Candidatus Phytoplasma asteris’ (group 16SrI) and ‘Candidatus Phytoplasma fraxini’ (16SrVII) by RFLP and sequencing of samples from commercial plots. Of 152 symptomatic and non-symptomatic potato plants tested, 33.5% were positive for one of the identified phytoplasmas or both (mixed infections). Phytoplasmas were also observed by electron microscopy in symptomatic plants. Both phytoplasmas were transmitted in tubers produced by infected plants and by the insect vector Exitianus atratus (Hemiptera: Cicadellidae) to healthy test potato plants. Daughter plants from infected tubers and the healthy plants inoculated via the insect vector developed the same symptoms observed in field grown potato plants, in single and mixed infections of both phytoplasmas. Our results confirm the presence of a new disease of potato in Cundinamarca, Colombia, which we named yellowing and rolling-leaf phytoplasma (fitoplasma del amarillamiento y enrrollamiento de hojas).

Epidemiological characterization of a disease associated with phytoplasmas in Andean oak, Quercus humboldtii Bonpland, in Bogotá—Colombia

AbstractQuercus humboldtii is the dominant tree species in oak forest ecosystems in the Colombian Andes, and approximately 15,000 trees have been planted in urban Bogotá. In Bogotá, Q. humboldtii is affected by phytoplasmas. The management of phytoplasmas relies mainly on control of the insect vectors. The aim of this work was to generate information on phytoplasmas affecting Q. humboldtii and the potential insect vectors involved. Phytoplasmas were detected by nested PCR and identified by restriction fragment length polymorphism or sequencing analysis of the 16S rRNA gene in 238 randomly selected urban trees, from 17 city zones. The prevalence of the disease was 80%, with phytoplasmas detected in 94% of trees. ‘Candidatus Phytoplasma fraxini’ was found in 54.6%, ‘Candidatus Phytoplasma asteris’ in 30.7% and mixed infections of both phytoplasmas in 8.8% of the trees. Phytoplasmas were observed in the phloem of infected trees by electron microscopy. ‘Ca. P. fraxini’ was more common than ‘Ca. P. asteris’ in both street and parks trees, but correlations between the phytoplasma and disease‐associated variables were not observed. The entomofauna of a subsample of 102 of these trees was examined. Representative specimens of seven orders were collected, with Hemiptera the most prevalent. Specimens of 17 Cicadellidae, one Membracidae and one Psyllidae species were collected. Cicadellidae species from subfamilies Aphrodinae, Deltocephalinae, Iassinae, Eurymelinae, Megophthalminae and Typhlocybinae were found, in which phytoplasma vectors have been reported previously. Specimens of two known Cicadellidae vector species were collected: Amplicephalus funzaensis (Deltochephalinae) and Exitianus atratus (Deltochephalinae). Phytoplasmas were assessed in 103 Cicadellidae specimens. ‘Candidatus P. asteris’ was detected in A. funzaensis (n = 3/16 tested), E. atratus (n = 2/10 tested) and Alebrini sp. 1 (n = 1/11) tested). The possible epidemiological implications of these findings are discussed.

Phytoplasma fraxini (ash yellows)

Phytoplasma fraxini (ash yellows)

Phytoplasma of 16SrVII-B subgroup associated to shoot proliferation in Physalis peruviana plants

Physalis is an herbaceous species native to the Andes region. Currently, it is cultivated in various Brazilian states due to the economic interest of growers for this new fruit. Physalis plants grown in the field showed symptoms of shoot proliferation, leaf malformation, and chlorosis. Since these symptoms are commonly induced by phytoplasmas, this study investigated to confirm the presence of these prokaryotes in symptomatic plants. After DNA extraction from symptomatic and asymptomatic plants, phytoplasmas were found in all affected plants through the nested PCR. Examination by transmission electron microscopy (TEM) using appropriately prepared segments of leaf veins allowed the visualization of typical pleomorphic cells of phytoplasmas in the phloem of symptomatic plants. The computer-simulated RFLP patterns and the phylogenetic analysis allowed identifying the detected phytoplasmas as a ‘Candidatus Phytoplasma fraxini’-related strain belonging to the 16SrVII-B subgroup. Moreover, physalis was identified as an additional host species for phytoplasmas in the 16SrVII group, expanding the current knowledge on the host range of phytoplasmas in this group.

First report of a ‘Candidatus Phytoplasma fraxini’‐related strain associated with witches’‐broom of Arizona ash

First report of a ‘<i>Candidatus</i> Phytoplasma fraxini’‐related strain associated with witches’‐broom of Arizona ash

Diversity of the ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma fraxini’ isolates that infect urban trees in Bogotá, Colombia

Phytoplasmas have been associated with a disease that affects trees of at least 11 species from different botanic families in Bogotá, Colombia. 'Candidatus Phytoplasma asteris' and 'Candidatus Phytoplasma fraxini' are the major groups of phytoplasma in the area of Bogotá. In this study, the genetic diversity within 'Ca. P. asteris' and 'Ca. P. fraxini' was studied in five urban tree species: Croton species (Euphorbiaceae), Fraxinus uhdei (Oleaceae), Magnolia grandiflora (Magnoliaceae), Populus nigra (Salicaceae) and Quercus humboldtii (Fagaceae). Analyses of the 16S rRNA gene using nested PCR, RFLP and sequencing showed that phytoplasmas of 'Ca. P. asteris' could be assigned to: subgroup 16SrI-B; a new subgroup named 16SrI-AF, with a restriction pattern similar to that of 16SrI-B; and a new subgroup named 16SrI-AG, with a restriction pattern similar to that of 16SrI-K and 16SrI-AH with a restriction pattern similar to that of 16SrI-AC. 'Ca. P. fraxini' isolates belonged to a new subgroup named 16SrVII-G, with a restriction pattern similar to that of 16SrVII-A. To complement the identification of the phytoplasma strains, we amplified nonribosomal genes such as leuS and secA. Unexpectedly, it was observed that in 16 trees in which 16S rRNA gene analysis showed the presence of 'Ca. P. fraxini' only, the leuS or secA primers amplified sequences exclusively affiliated to 'Ca. P. asteris. In those plants, sequences belonging to 'Ca. P. fraxini' leuS or secA genes were not amplified. The present work contributes to the identification of novel strains of both species in Colombia, and supports previous suggestions that phytoplasmas in South America are highly variable.

First Report of a ‘Candidatus Phytoplasma fraxini’-Related Strain Associated with Potato in Colombia

First Report of a ‘<i>Candidatus</i> Phytoplasma fraxini’-Related Strain Associated with Potato in Colombia

Molecular Detection of Grape Decline Phytoplasma in Leafhopper Species Associated with Infected Grapevines in Iran

Following recent detection of ‘Candidatus Phytoplasma fraxini’, ‘Ca. P. aurantifolia’, ‘Ca. P. solani’ and ‘Ca. P. phoenicium’-related strains in Iranian vineyards, a survey was conducted in 2016–2017 in vineyards located in Qazvin province of Iran. Nested PCR analysis was performed to identify phytoplasma strains in leafhopper species. The overall, less than 5% of grapevine trees shows phytoplasma symptoms and phyto-plasma was detected in all symptomatic samples. Phytoplasma DNA was detected in two leafhopper species. Most leafhopper species in which phytoplasma DNA were detected are recorded to be grass feeders, among which, Stolbur phytoplasma vectors, i.e. Psammotettix alienus (Dahlbom 1851) and Agallia ribauti (Ossian-nilsson, 1938), showed a strong potential ability for ‘Ca. P. solani’ transmission in Qazvin vineyards. The possibility of phytoplasma transmission between leafhoppers and grapevines is discussed.

Incidence and characterization of the presence of phytoplasmas in Fraxinus uhdei related with Ash Yellow disease in Colombia

For a long time, Urapan trees (Ash) have been a popular plant in parks and avenues in the principal cities of the Andes in Colombia, but now more than 53,000 trees are infected and many of them died. In 2004, the presence of phytoplasmas in the phloem of some trees with dieback symptoms was reported. In this study, the phytoplasma’s presence has been detected in all the tested Fraxinus uhdei (Wenz.) (common name, Urapan), using microscopy techniques like optical microscopy, transmission electron microscopy, and DAPI fluorescent microscopy, which indicated a further spread of the disease. The presence of phytoplasmas in the phloem of the leaves of Urapan trees was evident and related with the symptoms of the disease “Ash Yellows”. Here the relation phytoplasmas–disease symptoms have been confirmed by reproducing the symptoms through phytoplasmas transfection in Periwinkle (Catharanthus roseus) by using the ectoparasite Cuscuta campestris. The molecular analysis using PCR with universal primers of the region 16S-23S rDNA (P1/Timt, R16mF2/R16mR1, fB1/P7, fPD/Tint, F1/P7, Phytuf22/Phytuf24) confirmed the parasite’s presence and its identification as Ash Yellows phytoplasma or Candidatus Phytoplasma fraxini which belongs to the phytoplasma group 16SrVII and subgroup 16SrVII-A. These results permit to suggest a possible treatment with antibiotics that would avoid the species extinction throughout the Andes cities.

Molecular characterization of a phytoplasma affiliated with the 16SrVII group representative of the novel 16SrVII-F subgroup.

Vernonia brasiliana is a wild perennial shrub frequently found in pasture areas. Plants of this species have been observed displaying typical symptoms induced by phytoplasmas, which were characterized by shoot proliferation, deformed leaves and leaf chlorosis. The present study confirmed the presence of phytoplasmas in association with affected plants. Sequencing of the 16S rRNA gene, computer-simulated RFLP analysis and phylogenetic analysis revealed that one of the phytoplasmas identified was representative of novel subgroup. The sequence identity scores between the novel strain and those of previously described 'CandidatusPhytoplasma fraxini'-related strains was 99 %, while similarity coefficient values were lower than 0.97. These findings provide support to delineate the phytoplasma found in vernonia plants as a reference phytoplasma for a novel subgroup designated 16SrVII-F. This representative of the novel subgroup was denominated VbSP phytoplasma (Vernonia brasiliana Shoot Proliferation; GenBank KX342018). The results of the present study revealed V. brasiliana to be a host of phytoplasmas, evidenced a novel phytoplasma associated with phytoplasmal disease in Brazil and extended the knowledge of the genetic diversity existing within the 16SrVII group.

Molecular identification of diverse ‘Candidatus Phytoplasma’ species associated with grapevine decline in Iran

AbstractGrapevine (Vitis vinifera) is one of the most important fruits in Iran where the provinces of Qazvin, Lorestan and Markazi are main producers. During 2013–2015, vineyards located in these provinces were surveyed to verify the presence of phytoplasma. The sample collection was based on symptomatology including decline, leaf yellowing and shortening of internodes. Total DNA was extracted from symptomatic and symptomless grapevine samples and used in nested‐polymerase chain reaction (PCR) assays with phytoplasma ribosomal primers (P1/Tint followed by R16F2n/R2, R16mF1/mR1, R16(I)F1/R1 or 6R758f/16R1232r). Nested‐PCR products were obtained only for symptomatic samples while samples from symptomless plants yielded no PCR products. Restriction fragment length polymorphism (RFLP) analyses with Tru1I, TaqI and Tsp509I and direct sequencing of amplicons followed by phylogenetic analyses indicated the presence of ‘Candidatus Phytoplasma fraxini’, ‘Ca. P. aurantifolia’, ‘Ca. P. solani’ and ‘Ca. P. phoenicium’‐related strains. In Marzaki province, there ‘Ca. P. aurantifolia’ strains were mainly detected, while in the other two provinces, all the four ‘Candidatus species’ were identified with the prevalence of ‘Ca. P. solani’‐related strains. In both provinces in one case, mixed phytoplasma infection was also detected by RFLP analyses. The presence of different phytoplasmas in positive samples indicates great phytosanitary significance due to grapevine economic importance for country. Grapevine phytoplasma infection represents a threat for other crops suggesting grapevine as alternative host species for the phytoplasmas already reported in Iran, while the ‘Ca. P. fraxini’ is for the first time identified in Iran.

Candidatus phytoplasma fraxini related (16S rRNAVII) strain associated with date yellows disease in Iran

Phytoplasma was detected in date palm trees (Phoenixdactylifera) displaying symptoms of yellowing disease by nested polymerase chain reaction using 16SrRNA gene universal primers of phytoplasmas. Sequence identities of 98 % were found to several isolates of ‘Candidatus Phytoplasma fraxini’ (Ash yellows group, 16SrVII group).

First finding of a ‘Candidatus Phytoplasma fraxini‘‐related strain associated with disease of olive in Iran

Iran is becoming a globally significant olive producer. During a survey in 2015, olive trees with symptoms of shoot proliferation, stunting, yellowed and little leaves (Fig. 1) typical of phytoplasma infection were observed in Roudbar region, Gilan province, Iran. Approximately 35% of the samples collected showed symptoms. To determine if a phytoplasma was associated with the disease, total DNA was extracted using a CTAB-based method (Doyle & Doyle, 2) from leaves of five healthy and 20 diseased trees. DNA was analysed by PCR using phytoplasma universal primers P1/P7 (Ahrens & Seemuller, 1) in first round PCR, and R16F2n/R16R2 (Gundersen & Lee, 3) in nested PCR. This resulted in fragments of the expected size in all symptomatic plants. All of the healthy plants tested negative for phytoplasmas. The nested PCR product of one sample was sequenced directly (using primers R16F2n/R16R2) on both strands by Macrogen Co. (Korea). Sequences were assembled using SeqMan (Lasergene), manually adjusted when necessary, and deposited in GenBank (Accession No. KX298840). BLAST analysis of the 16Sr DNA showed the highest identity (99%) with members of the 16SrVII phytoplasma group. Phylogenetic analysis with other related phytoplasmas using ClustalX and MEGA6 identified the phytoplasma, designated olive little leaf phytoplasma, as a ‘Candidatus Phytoplasma fraxini‘-related strain (Fig. 2), with 99% sequence identity to the reference strain of the species (Ashy4, JQ868445). These results extend the geographical distribution and host range of ‘Ca. P. fraxini’. To our knowledge this is the first report of a phytoplasma related to ‘Ca. P. fraxini’ infecting olive, and the study of natural reservoirs and vectors will be important to understand this disease.

Leafhoppers Exitianus atratus and Amplicephalus funzaensis transmit phytoplasmas of groups 16SrI and 16SrVII in Colombia

The phytoplasmas of groups 16SrI (‘Candidatus Phytoplasma asteris’) and 16SrVII (‘Ca. Phytoplasma fraxini’) have been associated with phytoplasma diseases in several urban tree species in Bogotá, Colombia and surrounding areas. The insect vectors responsible for this phytoplasma transmission are unknown. The objectives of this study were to test for the presence of phytoplasmas in leafhopper species (Cicadellidae) collected in areas with diseased trees and to determine the phytoplasma transmission ability of two of these species. Leafhoppers of nine species were collected at two sampling sites and tested by nested or double nested PCR using primers for the 16S rRNA gene. The amplicons were subjected to RFLP and/or sequencing analysis. Phytoplasmas of group 16SrI were detected in morphospecies MF05 (Haldorus sp.), group 16SrVII in MF07 (Xestocephalus desertorum), MF08 (Empoasca sp.) and MF09 (Typhlocybinae), and both groups 16SrI and 16SrVII in MF01 (Empoasca sp.), MF02 (Typhlocybinae), MF03 (Scaphytopius sp.), MF04 (Amplicephalus funzaensis) and MF06 (Exitianus atratus). Transmission tests to uninfected bean plants (Phaseolus vulgaris) were performed using field collected A. funzaensis and E. atratus individuals in separate assays. After 5 weeks, the test plants exposed to individuals of both species of leafhoppers showed symptoms, suggesting phytoplasma infection. Phytoplasma groups 16SrI and 16SrVII were detected in the two groups of exposed plants, indicating that A. funzaensis and E. atratus were able to transmit both groups of phytoplasmas. This is the first report of insect vectors for phytoplasmas of group 16SrVII in the world and of 16SrI in South America.

A novel subgroup 16SrVII-D phytoplasma identified in association with Erigeron witches' broom.

Erigeron sp. plants showing symptoms of witches' broom and stunting were found near orchards of passion fruit in São Paulo state, Brazil. These symptoms were indicative of infection by phytoplasmas. Thus, the aim of this study was to detect and identify possible phytoplasmas associated with diseased plants. Total DNA was extracted from symptomatic and asymptomatic plants and used in nested PCR conducted with the primer pairs P1/Tint and R16F2n/16R2. Amplification of genomic fragments of 1.2 kb from the 16S rRNA gene confirmed the presence of phytoplasma in all symptomatic samples. The sequence identity scores between the 16S rRNA gene of the phytoplasma strain identified in the current study and those of previously reported 'Candidatus Phytoplasma fraxini'-related strains ranged from 98% to 99% indicating the phytoplasma to be a strain affiliated with 'Candidatus Phytoplasma fraxini'. The results from a phylogenetic analysis and virtual RFLP analysis of the 16S rRNA gene sequence with 17 restriction enzymes revealed that the phytoplasma strain belongs to the ash yellows phytoplasma group (16SrVII); the similarity coefficient of RFLP patterns further suggested that the phytoplasma represents a novel subgroup, designated 16SrVII-D. The representative of this new subgroup was named EboWB phytoplasma (Erigeron bonariensis Witches' Broom).

First Report on Natural Infection of Paeonia tenuifolia by 'Candidatus Phytoplasma solani' in Serbia.

Peony (Paeonia tenuifolia L.) is a herbaceous perennial plant known for its beautiful and showy flowers. In Serbia it is native to the Deliblato Sands and is used as an ornamental and medicinal plant in folk medicine. This plant species has become a rarity and for that reason peony was introduced into a botanical collection near Backi Petrovac (northern Serbia), where it has been maintained since 1988. Reddening of lower leaves observed on 10% of plants (5 of 50) in the collection at flowering in May 2012 gradually progressed throughout affected plants by the seed maturation stage. Five leaves from each of three reddened and three symptomless plants were sampled at the end of July 2012. Total nucleic acid was extracted separately from individual leaves (30 samples) using the CTAB (cetyltrimethylammonium bromide) method (2). A nested PCR assay using universal primer pairs P1/P7, followed by R16F2n/R16R2 (4), amplified 16S rDNA fragments of 1.8 and 1.2 kb, respectively. DNA from all three reddened plants (15 samples) yielded 1.2-kb amplicons after nested PCRs. Restriction fragment length polymorphism (RFLP) patterns obtained by digestion of nested products with endonucleases AluI, TruI, HpaII, or HhaI (Thermo Scientific, Lithuania) (4) were identical to those of the STOL reference strain included for comparative purposes, indicating that symptoms were consistently associated with plant infection by 'Ca. Phytoplasma solani' (Stolbur) phytoplasma. The 16S rDNA amplicons from two peony plants (1.2 kb from B15 and 1.8 from B18) were sequenced (GenBank Accession No. KC960487 and KF614623, respectively). BLAST analysis revealed a 100% identity between the sequences and GenBank sequences of Stolbur phytoplasma, subgroup 16SrXII-A phytoplasma, previously detected in maize (JQ730750) in Serbia and red clover (EU814644.1) in the Czech Republic. Phytoplasma associated diseases of other species of the genus Paeonia (P. lactiflora Pall. and P. suffruticosa Andrews) have been described elsewhere. Disease symptoms on P. lactiflora from Chile were associated with the phytoplasma that belongs to the ribosomal subgroup 16SrVII-A ('Ca. Phytoplasma fraxini') (1). Also, Stolbur phytoplasma from the 16SrXII group was detected on P. suffruticosa plants in China, manifesting yellowing symptoms (3). To our knowledge, this is the first report of naturally occurring Stolbur phytoplasma disease of P. tenuifolia L. in Serbia.

Erigeron(Conyza)bonariensis, a host of ‘CandidatusPhytoplasma fraxini’-related strain in Brazil

Erigeron bonariensis, the flax-leaved fleabane is found in several regions of Brazil. In the State of Rio de Janeiro, plants of E. bonariensis exhibiting shortened internodes, reduced leaf size, witches’ broom and yellowing were tested for phytoplasma presence. Amplicons were obtained from nested PCR with primers designed for 16S rRNA and tuf genes. RFLP analyses of the ribosomal DNA revealed similarity to phytoplasmas of the ash yellows group and sequence analyses demonstrated 100% identity with phytoplasma strains belonging to subgroup 16SrVII-B from Argentina and Brazil. The sequence from tuf gene showed a maximum of 94% identity with ‘Candidatus Phytoplasma fraxini’ strain ASY3, and 92% identity with other strains of the ash yellows group. To our knowledge, this is the first report of the species Erigeron bonariensis harboring a ‘Ca. P. fraxini’-related strain in Brazil.