First Report of Phytoplasma Belonging to Apple Proliferation Group in Roses in Poland

Virus-like diseases of rose plants of uncertain aetiology have been widely distributed throughout the world (4). Symptoms include dieback, rose rosette, witches' broom, and bud proliferation. Research conducted in England (4) and the United States (1) could not reveal the etiology of the diseases. Disease symptoms including stunted growth, leaf and flower malformation, and shoot and flower proliferation were observed in rose plants in Poland (2). In this previous work, we reported cases of phytoplasma closely related to group 16SrI in rose plants with shoot proliferation as determined by nested polymerase chain reaction (PCR) with ribosomal primers R16F1/R0 followed by rA/fA or R16(I)F1/R1. In this study, we examined 48 symptomatic rose plants of 12 cultivars using nested PCR primed by P1/P7 and followed by universal primer pairs R16F2n/R2, fA/rA, or group 16SrI-specific R16(I)F1/R1. To detect potential mixed infection in roses, the group 16SrX-specific primer pairs fAT/rAS, fAT/rPRUS, and fPD/rAT were used for nested PCRs. Samples of rose plants with disease symptoms and nonsymptomatic, samples of Catharanthus roseus, healthy and inoculated by grafting with the reference strain of aster yellows phytoplasma (AY1, group 16SrI-B, kindly supplied by I.-M. Lee, Beltsville, MD) and the reference strain of apple proliferation phytoplasma (AP, group 16SrX-A, kindly supplied by A. Bertaccini, Bologna, Italy), were tested for the presence of phytoplasma rDNA by PCR. Phytoplasma identification was accompanied by digestion with restriction endonucleases, AluI, HhaI, HpaII, MseI, and RsaI, and restriction fragment length polymorphism (RFLP) analysis of a 1.2-kb fragment of rDNA (3). A DNA amplification product was observed in all nested PCRs containing template DNA of samples collected from diseased roses and the reference strains but not from control plants. On the basis of RFLP analysis of PCR products and comparison of the RFLP patterns with those of the reference strains, we demonstrated the presence of aster yellows phytoplasma belonging to phytoplasma group 16SrI-B in roses of 11 cultivars. RFLP profile of samples collected from rose cv. Red Champ was identical to those obtained for reference AP strain (group 16SrX-A). Mixed RFLP profiles were observed in samples collected from rose cv. Memory, which were doubly infected by phytoplasmas belonging to groups 16SrI-B or 16SrX-A. These results were confirmed by PCR with group 16SrX-specific primer pairs. The target DNA was amplified when amplifications were conducted with subgroup 16SrX-A-specific primer pair fAt/rAS, whereas no observable PCR products were obtained with subgroup 16SrX-B- (fAT/rPRUS) or 16SrX-C- (fPD/rAT) specific primer pairs. This report confirms infection of roses by aster yellows phytoplasma belonging to group 16SrI-B, and to our knowledge, records for the first time, infection by phytoplasma of group 16SrX-A. References: (1) A. H. Epstein and J. H. Hill. J. Phytopathol. 143:353, 1995. (2) M. Kami ska et al. J. Phytopathol. 149:3, 2001. (3) I.-B. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1968. (4) B. J. Thomas. Ann. Rep. Glasshouse Crops Res. Inst. 1979:178, 1981.

Download Full-text

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.

Download Full-text

Molecular characterization of stolbur phytoplasmas in pepper and tomato from Bulgaria

BIO Web of Conferences ◽

10.1051/bioconf/20201800025 ◽

2020 ◽

Vol 18 ◽

pp. 00025

Author(s):

Dimitriyka Sakalieva

Keyword(s):

Molecular Characterization ◽

Reference Strain ◽

Rflp Analysis ◽

Plant Diseases ◽

Vegetable Crops ◽

Disease Symptoms ◽

Natural Plant ◽

Conserved Genes ◽

Reference Strains

Tomato and pepper are the main vegetable crops cultivated in Bulgaria. Phytoplasma diseases, mainly stolbur, are important plant diseases for these crops in Bulgaria. The goal of the present paper was to verify association of phytoplasmas with the observed disease symptoms in tomato and pepper and to identify the phytoplasmas detected using RFLP analysis of conserved genes and other uncharacterised phytoplasma chromosomal regions. The presence of phytoplasmas was confirmed in all the samples of tomato and pepper showing typical stolbur symptoms. A phytoplasm sample, which caused severe symptoms, showed the same pattern as the reference strain Mol, while all other phytoplasmic reference strains showed different polymorphisms. RFLP profiles were found useful in distinguishing phytoplasmas in stolbur subgroup (16SrXII-A) in natural plant hosts.

Download Full-text

Detection and molecular characterization of phytoplasmas infecting apple trees in Poland

Horticultural Science ◽

10.17221/181/2013-hortsci ◽

2014 ◽

Vol 41 (No. 1) ◽

pp. 27-33 ◽

Cited By ~ 1

Author(s):

M. Cieślińska ◽

D.E. Kruczyńska

Keyword(s):

Rflp Analysis ◽

Rrna Gene ◽

Apple Trees ◽

Aster Yellows ◽

Candidatus Phytoplasma Mali ◽

Multiple Alignments ◽

Pcr Rflp ◽

Aster Yellows Phytoplasma ◽

Reference Strains

During 2010–2012, samples from 225 apple trees growing in six regions of Poland were tested for phytoplasmas. 16S rRNA gene and 16S-23S spacer region sequences were amplified from total DNAs prepared from phloem tissue of apple shoots. According to the results of PCR-RFLP and sequence analyses, apple trees were infected by Candidatus Phytoplasma mali and Ca. P. asteris. Fragments of 16S rDNA plus 16S-23S spacer region of the Ca. P. mali isolates digested with HpaII enzyme showed two restriction profiles: P-I and P-II. Multiple alignments of 16S rRNA gene fragments revealed that the isolates of Ca. P. mali shared 100% sequence identity among themselves as well as with reference strains AT and AP-15 of apple proliferation phytoplasma. The nucleotide sequence of the same region of <br /> Ca. P. asteris isolates confirmed the phylogenetic relationship with reference strains OAY (MIAY) and AY1 of aster yellows phytoplasma PCR-RFLP analysis of ribosomal protein (rpl22 and rpS3), secY, and tuf genes did not show the sequence diversity of the isolates of aster yellows phytoplasma.    

Download Full-text

First Report of a Member of Aster Yellows Phytoplasma Group and of Clover Proliferation Phytoplasma Group Associated with Onion in Texas

Plant Disease ◽

10.1094/pdis.2001.85.4.448a ◽

2001 ◽

Vol 85 (4) ◽

pp. 448-448 ◽

Cited By ~ 3

Author(s):

I.-M. Lee ◽

R. A. Dane ◽

M. C. Black

Keyword(s):

Type A ◽

The United States ◽

23S Rrna ◽

Type B ◽

Aster Yellows ◽

First Report ◽

Severe Stunting ◽

Pcr Products ◽

Aster Yellows Phytoplasma ◽

Symptom Type

An unknown disease(s) emerged this spring (2000) in an onion field in southwestern Texas. Infected onion plants exhibited two symptom types, one with shoot proliferation, moderate stunting of plants, and light yellowish discoloration on leaves (A) and the other with only severe stunting of the plants (B). The bulbs of the infected plants collected from both symptom types were smaller than normal. When the aerial shoots were trimmed, the infected (but not asymptomatic or the severely stunted) bulbs produced multiple slender sprouts after storage in room temperature for about a month. These symptoms are characteristic of yellows diseases caused by phytoplasmas. Ten symptomatic (six with symptom type A and four with symptom type B) and ten symptomless onion plants were collected in early May from an onion field about 1 to 2 weeks prior to blooming. Total nucleic acid was extracted from 0.5 g of shoot tissues from each sample. Nested polymerase chain reaction (PCR) using universal primer pairs (P1/P7 followed by R16F2n/R16R2) previously designed based on 16S and 23S rRNA gene sequence (1,2) was employed for the detection of phytoplasma(s) present in the samples. Specific PCR products (all were about 1.2 kb) were heavily amplified from five samples with symptom type A and one with symptom type B. Three of the symptomatic plants showing symptom type B and five of the symptomless samples were scored as weak positives. Restriction fragment length polymorphism (RFLP) analyses of the PCR products obtained from all five symptomatic samples with symptom type A using restriction enzymes including MseI, HhaI, and HpaII revealed that the associated phytoplasmas detected belonged to aster yellows phytoplasma group (16SrI), subgroup A. RFLP analyses of PCR product from the sample with symptom type B indicated that the associated phytoplasma belonged to clover proliferation group (16SrVI), subgroup A (1). Since symptom type A resembles onion yellows reported elsewhere, we propose to adopt “onion yellows” to refer to the new onion disease occurring in Texas. However, correlation between a member of clover proliferation phytoplasma group and onion plants showing severe stunting could not be firmly established. A phytoplasma belonging to 16SrI-B is associated with onion yellows disease reported in Japan (1). This is the first report that onion yellows occurs in the United States. 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.

Download Full-text

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.

Download Full-text

First Report of Phytoplasma Infection in Hop Plants

Plant Disease ◽

10.1094/pdis.2004.88.8.908b ◽

2004 ◽

Vol 88 (8) ◽

pp. 908-908 ◽

Cited By ~ 1

Author(s):

E. Solarska ◽

M. Kamińska ◽

H. Śliwa

Keyword(s):

Natural Infection ◽

Shoot Proliferation ◽

Rflp Analysis ◽

Enzymatic Digestion ◽

Early Spring ◽

Direct Pcr ◽

Universal Primer ◽

Disease Symptoms ◽

Group Specific Primer ◽

Reference Strains

Disease symptoms of severe shoot proliferation resembling phytoplasmal disease symptoms were observed in early spring of 2003 in hop (Humulus lupulus L.) plant cvs. Magnum and Marynka that were grown in a commercial farm in Poland. Proliferation of shoots has not been previously reported in hop plants. To detect the presence of phytoplasmas in hops, young shoots from four symptomatic (two cultivars) and two symptomless (‘Magnum’) plants were assayed for phytoplasma 16S rDNA using polymerase chain reaction (PCR). In addition, leaf samples from healthy Catharanthus roseus plants and plants experimentally infected with the reference strains of aster yellows phytoplasma (AY1, group 16SrI-B) or apple proliferation phytoplasma (AP, group 16SrX-A) were included for comparison. Amplifications were performed using the universal phytoplasma primer pair P1/P7 in an initial assay, and universal primer pairs fA/rA (1), Pc399/P1694, or R16F2n/R16R2 (2) and group specific primer pair R16(I)F1/R16(I)R1 (3) in a nested reaction. Specific products were obtained in direct PCR with the universal primer pairs P1/P7 only for the control samples of the reference strains AY and AP. No visible product was amplified by the direct PCR from samples obtained from hops and healthy periwinkle plants. However, in nested PCR with primer pairs P1/P7 followed by primer pairs fA/rA, R16F2n/R16R2, Pc399/P1694, or R16(I)F1/R16(I)R1, specific DNA bands were observed from naturally infected hop plants (both four symptomatic and two symptomless) tested. No amplification products were observed from healthy periwinkle plants. The specificity of PCR products (obtained with universal R16F2n/R16R2 primer pair) was confirmed by restriction fragment length polymorphism (RFLP) analysis using AluI, MseI, HhaI, and RsaI for enzymatic digestion. RFLP patterns of these rDNA fragments for samples of naturally infected hops and for AY1 reference strain were similar and were characteristic of phytoplasma 16SrI-B subgroup. To our knowledge, this is the first evidence that hop shoot proliferation disease is associated with natural infection by phytoplasmas. Furthermore, detection of phytoplasma in asymptomatic hops underscores the need to fully elucidate the etiological role of this pathogen in the disease. References: (1) U. Ahrens and E. Seemüller. Phytopathology 82:828, 1992. (2) I.-M. Lee et al. Phytopathology 83:834, 1993. (3) I.-M. Lee et al. Phytopathology 84:559, 1994.

Download Full-text

‘Candidatus Phytoplasma brasiliense’ (16SrXV-A Subgroup) Associated with Cauliflower Displaying Stunt Symptoms in Brazil

Plant Disease ◽

10.1094/pdis-09-12-0874-pdn ◽

2013 ◽

Vol 97 (3) ◽

pp. 419-419 ◽

Cited By ~ 8

Author(s):

M. C. Canale ◽

I. P. Bedendo

Keyword(s):

Nested Pcr ◽

Sequence Similarity ◽

Rflp Analysis ◽

The United States ◽

Rrna Gene ◽

New Host ◽

Rdna Sequences ◽

Pcr Products ◽

Virtual Rflp ◽

In The Beginning

Cauliflower stunt, caused by a phytoplasma of the group 16SrIII-J, was reported in the beginning of 2012 and has occurred with high incidences of infected plants (up to 90%) in crops located in the state of São Paulo in the southeast region of Brazil (3). Diseased plants exhibit general stunting, malformation of inflorescence, reddening leaves, and vessel necrosis (3). Further investigations with plants displaying identical symptoms collected in Nova Bassano, state of Rio Grande do Sul, Brazilian south region, have revealed the presence of a phytoplasma distinct from 16SrIII-J subgroup. Four symptomatic plus four asymptomatic samples were assayed from a field, and the presence of phytoplasma was evidenced by nested PCR assays performed with primers P1/Tint followed by R16F2n/16R2 in three affected plants, which amplified genomic fragments of 1.2 kb from the 16S rRNA gene. No amplification occurred in non-affected samples. Nested PCR products analyzed by conventional RFLP (2) using the enzymes AluI, RsaI, KpnI, HpaII, MseI, HhaI, MboI, and BstUI pointed to the presence of a phytoplasma belonging to group 16SrXV-A in all three phytoplasma-positive samples. Virtual RFLP analysis based on restriction patterns, derived from in silico digestion with 17 endonucleases (4), confirmed the previous results obtained from those samples by conventional RFLP. The 16S rDNA sequences of this phytoplasma identified in cauliflower (GenBank Accession No. JN818845) shared 99% sequence similarity with the reference phytoplasma for subgroup 16SrXV-A (Hibiscus witches'-broom phytoplasma, AF147708), designated ‘Candidatus Phytoplasma brasiliense.’ Analysis of putative restriction sites showed excellent identity between the phytoplasma studied here and the reference phytoplasma. In addition, the arrangement of branches of a phylogenetic tree constructed with phytoplasmas representing diverse 16Sr groups and subgroups supported that the phytoplasma found in cauliflower is closed related to the representative of the subgroup 16SrXV-A. Association of distinct phytoplasmas with the same kind of disease is not rare and the present pathosystem constitutes a new example. Members of this subgroup have been described almost exclusively in Brazil and previously reported in Sida sp., periwinkle, and hibiscus (1). In some European countries, as well as in the United States and Canada, phytoplasmas belonging to group 16SrI has been associated with this type of disease, which has been reported for various species of the genus Brassica, as published in previous works (3). However, a representative of the group 16SrVI was described in infected plants in Iran (3). Although the 16SrIII-J phytoplasma is currently the most important agent of cauliflower stunt in Brazil, and members of 16SrI are prevalent in other countries, this study revealed that a 16Sr XV-A phytoplasma may be also associated with this important disease of brassicas. Besides, the findings here reported expand the natural host range, including cauliflower as new host for phytoplasmas affiliated with 16SrXV-A. References: (1) B. Eckstein et al. Plant Dis. 95:363, 2009. (2) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (3) M. C. C. Rappussi et al. Eur. J. Plant. Pathol. 133:829, 2012. (4) Wei et al. Int. J. Syst. Evol. Microbiol. 57:1855, 2007.

Download Full-text

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.

Download Full-text

First Report of Phytoplasmas Infecting Watercress in Hawaii

Plant Disease ◽

10.1094/pdis.2002.86.3.331a ◽

2002 ◽

Vol 86 (3) ◽

pp. 331-331 ◽

Cited By ~ 4

Author(s):

W. B. Borth ◽

R. T. Hamasaki ◽

D. Ogata ◽

S. K. Fukuda ◽

J. S. Hu

Keyword(s):

Leaf Size ◽

Nutritional Deficiencies ◽

Aster Yellows ◽

Pcr Products ◽

Mite Feeding ◽

Efficient Vector ◽

Phytoplasma Infection ◽

Macrosteles Quadrilineatus ◽

Aster Leafhopper ◽

Aster Yellows Phytoplasma

Symptoms of leaf yellowing, reduced leaf size, and witches'-brooms have recently been observed affecting watercress (Nasturtium microphyllum Boen. × Rcbh.) in Hawaii. These symptoms are followed by the collapse of affected plants. This condition has led to 80 to 90% losses for one of the largest watercress farms on Oahu and is now affecting other watercress farms in the area. Nutritional deficiencies or toxicities, water salinity, and insect or mite feeding damage were investigated but could not be implicated in the etiology of this syndrome. Eighteen watercress plants with early yellowing or advanced symptoms and nine symptomless plants were analyzed for phytoplasma infection using polymerase chain reaction (PCR) assays with primer pairs P1/Tint or P1/P7 (4). Amplicons of the expected sizes were produced from all symptomatic plants, whereas no products were amplified from symptomless plants. Sequence analysis of the cloned PCR products confirmed their phytoplasma origin and indicated that the watercress was infected with a phytoplasma most similar to SAY (2), a severe strain of western aster yellows phytoplasma previously classified as a 16SrI-B group member (3). Leafhoppers collected from an affected watercress planting have been identified as the aster leafhopper (Macrosteles quadrilineatus Fbs.) This species is the most efficient vector of the aster yellows phytoplasma and had not been previously recorded in Hawaii. The only other phytoplasma disease known in Hawaii prior to this report is Dodonaea yellows (1), which affects one of the most common native plants (Dodonaea viscosa (L.) Jacq.) in dry upland forests on all the islands. Dodonaea yellows, however, has been attributed to an X-disease (16SrIII) group phytoplasma. The occurrence of an aster yellows group phytoplasma in watercress, a previously unrecorded host, and the presence of a very efficient vector, M. quadrilineatus, poses a serious threat to the production of other vegetable and floral crops in Hawaii. References: (1) W. Borth et al. Plant Dis. 79:1094, 1995. (2) C. Kuske and B. Kirkpatrick. Int. J. Syst. Bacteriol. 42:226, 1992. (3) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (4) C. Smart et al. Appl. Environ. Microbiol. 62:2988, 1996.

Download Full-text

The influence of antibiotics on the appearance of magnolia stunting symptoms

Acta Agrobotanica ◽

10.5586/aa.2002.011 ◽

2013 ◽

Vol 55 (1) ◽

pp. 107-117

Author(s):

Maria Kamińska ◽

Hanna Śliwa

Keyword(s):

Host Plant ◽

Shoot Growth ◽

Natural Host ◽

Apple Proliferation ◽

Flower Buds ◽

Aster Yellows ◽

Pcr Rflp ◽

Growth Development ◽

And Control ◽

Aster Yellows Phytoplasma

Treatment of diseased magnolia plants with oxytetracycline, baytril and tylan did not reduce the number of symptomatic plants. However, the sprays with antibiotics promoted the shoot growth, development of symptomless leaves and flower buds. The most efficient were baytril at the concentration of 500 ppm, tylan 200 ppm and oxytetracycline at the concentration of 500 or 1000 ppm. Lower concentrations of baytril and oxytetracycline were not so much effective; higher concentration of tylan decreased the magnolia shoot growth. The effect of antibiotics lasted one season. All the antibiotic treated and control plants, randomly tested by PCR-RFLP, showed the presence of AY(16SrI) phytoplasma and some of them were affected with phytoplasma related with apple proliferation phytoplasma group (16SrX). The obtained results indicated that l). magnolia is a natural host plant of phytoplasmas belonging to aster yellows phytoplasma group and apple proliferation group and 2). they support the suggestion that phytoplasmas are the casual agents of magnolia stunting disease.

Download Full-text