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Phytoplasma
Kinds of Phytoplasma Terms modified by Phytoplasma Selected AbstractsCharacterization of A New Almond Witches' Broom Phytoplasma in IranJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2006M. Salehi Abstract Almond witches' broom (AlmWB) is a destructive disease in several provinces in Iran. Association of phytoplasma with the disease has been established previously. In the present work two phytoplasmas from Khafr (KAlmWB) and Neyriz (NAlmWB) in the Fars Province were compared by biological and molecular analysis. Both infected bitter almond, wild almond, peach and nectarine but not apple and pear, by grafting. In bitter almond the symptoms induced by KAlmWB consisted of severe proliferation, internode shortening and leaf size reduction. In contrast, NAlmWB caused leaf necrosis, dieback and death. KAlmWB was transmitted to periwinkle and eggplant and from experimentally infected periwinkle to almond by dodder. It was also transmitted from eggplant to eggplant, ornamental eggplant and tomato by grafting. Under similar test conditions, NAlmWB was not transmitted to herbaceous plants by dodder. Phylogenetic analysis of 16S,23S rDNA spacer region (SR) sequences placed both strains in the pigeon pea witches' broom (PPWB) group. However, based on phylogenetic and putative restriction site analyses and sequence homology, NAlmWB was identical with the Lebanese AlmWB phytoplasma, while KAlmWB was closer to the Knautia arvensis phyllody (KAP) agent. Clustering of KAlmWB with KAP was confirmed by analysis of full length 16S rDNA sequence. On the basis of host range, dodder transmission, host range, symptomatology and molecular analyses of 16S rDNA and SR, two different phytoplasmas related to PPWB group were associated with AlmWB disease in Iran. KAlmWB phytoplasma is being reported as a new phytoplasma of AlmWB disease. [source] The Occurrence of Phytoplasmas in Apple Trees Showing Branch TwistingJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2005J. Fránová Abstract Apple trees showing malformation of branches were found at different locations in the Czech Republic. Ultrathin sections of tissues from diseased trees showed the presence of pleomorphic bodies resembling phytoplasma. Nested-polymerase chain reaction (PCR) assays with primers amplifying16S,23S ribosomal RNA (rRNA) sequences specific for phytoplasma and the subsequent restriction fragment length polymorphism (RFLP) analyses allowed to classify the detected phytoplasmas in the aster yellows group, subgroup 16SrI-C in 12 trees, single (11 plants) or mixed with phytoplasma belonging to subgroup 16SrI-B (1 plant). Phytoplasma of apple proliferation group (16SrX-A subgroup) were identified in cv. Mat,ino. Apple tree cv. P,e,tické r,,ové was infected by phytoplasma of the 16SrX-A and 16SrI-B subgroups. No phytoplasmas were detected in asymptomatic apple trees. [source] The Presence of Phytoplasma in Black Currant Infected with the Blackcurrant Reversion DiseaseJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2004Abstract A plant of black currant cv. Karl,tejnský dlouhohrozen showing symptoms of the severe Russian (R) form of the blackcurrant reversion disease (BCRD) was shown to contain phytoplasma bodies measuring 530,750 nm. Phytoplasma infection was confirmed by polymerase chain reaction (PCR) with the universal primer pair R16F1/R16R0, followed by PCR with the primer pair fU5/rU3. A comparison of the sequence of an amplification product of approximately 880 bp with sequences available in the GenBank confirmed the classification of the phytoplasma in the 16SrI (Aster yellows group). This is the first evidence of the natural occurrence of phytoplasma infection in black currant. Blackcurrant reversion virus (BRV), the cause of BCRD, was confirmed in the plant by RT-PCR. A 481 nt cDNA fragment of BRV was sequenced and compared with sequences in GenBank. Rhabdovirus-like particles were also observed in the plant by electron microscopy. [source] Phytoplasma associated with a witches' broom disease of Gleditsia sinensis (Fabaceae) newly reported in ChinaPLANT PATHOLOGY, Issue 4 2009H. Min No abstract is available for this article. [source] Phytoplasma from little leaf disease affected sweetpotato in Western Australia: detection and phylogenyANNALS OF APPLIED BIOLOGY, Issue 1 2006F. Tairo Abstract Symptoms of leaf and stem chlorosis and plant stunting were common in sweetpotato plants (Ipomoea batatas) in farmers' fields in two widely separated locations, Kununurra and Broome, in the tropical Kimberley region in the state of Western Australia in 2003 and 2004. In the glasshouse, progeny plants developed similar symptoms characteristic of phytoplasma infection, consisting of chlorosis and a stunted, bushy appearance as a result of proliferation of axillary shoots. The same symptoms were reproduced in the African sweetpotato cv. Tanzania grafted with scions from the plant Aus1 with symptoms and in which no viruses were detected. PCR amplification with phytoplasma-specific primers and sequencing of the 16S-23S rRNA gene region from two plants with symptoms, Aus1 (Broome) and Aus142A (Kununurra), revealed highly identical sequences. Phylogenetic analysis of the 16S rRNA gene sequences obtained from previously described sweetpotato phytoplasma and inclusion of other selected phytoplasma for comparison indicated that Aus1 and Aus142A belonged to the Candidatus Phytoplasma aurantifolia species (16SrII). The 16S genes of Aus1 and Aus142A were almost identical to those of sweet potato little leaf (SPLL-V4) phytoplasma from Australia (99.3%,99.4%) but different from those of the sweetpotato phytoplasma from Taiwan (95.5%,95.6%) and Uganda (SPLL-UG, 90.0%,90.1%). Phylogenetically, Aus1, Aus142A and a phytoplasma previously described from sweetpotato in the Northern Territory of Australia formed a group distinctly different from other isolates within Ca. Phytoplasma aurantifolia species. These findings indicate that novel isolates of the 16SrII-type phytoplasma pose a potential threat to sustainable sweetpotato production in northern Australia. [source] Grapevine flavescence dorée phytoplasmaEPPO BULLETIN, Issue 3 2007Article first published online: 7 DEC 200 First page of article [source] Rubber tree (Hevea brasiliensis) trunk phloem necrosis: aetiological investigations failed to confirm any biotic causal agentFOREST PATHOLOGY, Issue 1 2007F. Pellegrin Summary Trunk phloem necrosis (TPN) is currently a main constraint in rubber (Hevea brasiliensis) plantations. The apparent spread of the disease, from tree to tree along the planting line, strongly supported the implication of a pathogen that could be transmitted mechanically via the tapping knife. In order to detect a causal agent of the disease, studies focusing on characterization of the known mechanically transmitted pathogens (e.g. viroids, cryptic viruses or phytoplasma) were initiated. RNA strands of low molecular weight (200,400 and >500 bp) displaying structural similarities with viroids and viral dsRNAs were observed in various tested samples. However, attempts to show the potential role of these RNA molecules in the spread of the disease failed. First of all, there was no significant or reproducible correlation between the health status of the rubber trees sampled and these RNA molecules. Moreover, no sequence homology with known pathogens could be found when randomly amplified cDNA fragments isolated from trees presenting the disease symptoms were sequenced. In conclusion, the aetiological investigations, in order to show the presence of a pathogen responsible of the TPN disease, were non-conclusive, which tends to disprove the hypothesis of a biotic causal agent. [source] Infection of Bois-Noir tuf-type-I stolbur phytoplasma in Hyalesthes obsoletus (Hemiptera: Cixiidae) larvae and influence on larval sizeJOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2009C. Kaul Abstract Recent dramatic spread of the grapevine yellows disease Bois Noir (BN) in Germany is above all explained by highly increased abundances of the vector Hyalesthes obsoletus (Hemiptera: Cixiidae) associated to the plant Urtica dioica, the reservoir of the BN pathogen stolbur tuf-type-I. The vector acquires BN-phytoplasma as larvae whilst feeding on the roots of infected U. dioica. To understand the dynamics of the Urtica -cycle, we tested at what instar larvae become infected and whether infection affects larvae size (i.e. growth) at two sites in the Mosel Valley, Germany. Larvae were tested from infected plants and collected at instar-stages 3, 4 and 5. Larvae at stage 3 were already infected but infection rates increased significantly between stage 3 and 5, mean infection rates: 0.12,0.62. There was no effect of infection on larval size at any instar stage. [source] Grapevine yellows in Northern Italy: molecular identification of Flavescence dorée phytoplasma strains and of Bois Noir phytoplasmasJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007S. Botti Abstract Aims:, Verify the presence and the molecular identity of phytoplasmas in Northern and Central Italy vineyards where yellows diseases are widespread. Methods and Results:, Phytoplasma presence and identity were determined by PCR/RFLP analyses on 16S ribosomal gene testing 1424 symptomatic samples. The 65% of samples resulted phytoplasma infected; in particular 256 samples were found positive to phytoplasmas belonging to group 16SrV (mainly Flavescence dorée associated), and the remaining 37% was infected by phytoplasmas belonging to ribosomal subgroup 16SrXII-A (Stolbur or Bois Noir associated). 16SrV ribosomal group representative strains were further typed for variability in SecY and rpS3 genes. The results showed the presence of phytoplasmas belonging to 16SrV-C, 16SrV-D and to a lesser extent, 16SrV-A subgroup. Conclusions:, Possible relationships between genetic polymorphisms of phytoplasma strains belonging to subgroup 16SrV-C and their geographic distribution and/or epidemic situations were detected. Significance and Impact of the Study:, Bois Noir and Flavescence dorée phytoplasmas are present in significant percentages in the areas under investigation. Molecular tools allowed to identify phytoplasma-infected plants and the genes employed as polymorphism markers resulted useful in distinguishing and monitoring the spreading of the diseases associated with diverse phytoplasmas belonging to 16SrV subgroup in vineyards. [source] Identification and Molecular Characterization of ,Candidatus Phytoplasma mali' Isolates in North-western ItalyJOURNAL OF PHYTOPATHOLOGY, Issue 2 2010Paola Casati Abstract Apple proliferation (AP) is an important disease and is prevalent in several European countries. The causal agent of AP is ,Candidatus Phytoplasma mali' (,Ca. Phytoplasma mali'). In this work, isolates of ,Ca. Phytoplasma mali' were detected and characterized through polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses of 16S rRNA gene and non-ribosomal DNA fragment. The presence of three AP subtypes (AT-1, AT-2 and AP-15) was identified in 31 symptomatic apple trees and two samples each constituted by a pool of five insects, collected in north-western Italy, where AT-1 is a dominant subtype. Subsequent nucleotide sequence analysis of the PCR-amplified 1.8 kb (P1/P7) fragment, containing the 16S rDNA, the 16S,23S intergenic ribosomal region and the 5,-end of the 23S rDNA, revealed the presence of at least two phytoplasmal genetic lineages within the AT-1 subtype, designed AT-1a and AT-1b. Moreover, in silico single nucleotide polymorphism (SNP) analysis based on 16S rDNA sequence can differentiate AT-1 subtype from AT-2 and AP-15 subtypes. Our data showed a high degree of genetic diversity among ,Ca. Phytoplasma mali' population in north-western Italy and underlined the possible use of the 16S rDNA analysis for the identification and the geographical origin assignation of isolates of AP phytoplasma. Molecular markers on 16S rDNA, here identified, could be useful for studying the epidemiology of AP disease. [source] Molecular Characterization and Potential Insect Vector of a Phytoplasma Associated with Garden Beet Witches' Broom in Yazd, IranJOURNAL OF PHYTOPATHOLOGY, Issue 4 2007A. Mirzaie Abstract In 2002, garden beet witches' broom (GBWB) phytoplasma was detected for the first time in garden beet plants (Beta vulgaris L. ssp. esculenta) in Yazd, Iran. Nested polymerase chain reaction (PCR) and restriction fragment length polymorphic (RFLP) analysis of PCR-amplified phytoplasma 16S rDNA were employed for the detection and identification of the phytoplasma associated with garden beet. A phytoplasma belonging to subgroup 16SrII-E, in the peanut witches' broom group (16SrII), was detected in infected plants. Asymptomatic plant samples and the negative control yielded no amplification. The result of analysis of the nucleotide sequence of a 1428 bp fragment of 16S rDNA gene from GBWB phytoplasma (GenBank accession number DQ302722) was basically consistent with the classification based on RFLP analysis, in which GBWB phytoplasma clustered with phytoplasmas of the 16SrII-E subgroup. A search for a natural phytoplasma vector was conducted in Yazd in 2004, in an area where garden beet crops had been affected since 2002. The associated phytoplasma was detected in one leafhopper species, Orosius albicinctus, commonly present in this region. The leafhopper O. albicinctus was used in transmission tests to determine its vector status for the phytoplasma associated with GBWB. Two of eight plants that had been fed on by O. albicinctus, showed mild symptoms of GBWB including stunting and reddening of midveins. A phytoplasma was detected in the two symptomatic test plants by PCR using universal primers and it was identified by RFLP as the GBWB phytoplasma. This finding suggests O. albicinctus is a vector of the GBWB phytoplasma. [source] Diversity and Geographical Distribution of Phytoplasmas infecting China-tree in ArgentinaJOURNAL OF PHYTOPATHOLOGY, Issue 2 2007J. D. Arneodo Abstract Yellows diseases associated with phytoplasmas cause high mortality in China-tree (Melia azedarach) in Argentina, but there has been no previous large-scale survey to determine their diversity and geographical distribution. To assess the presence and identity of phytoplasmas affecting this species throughout the country, 425 samples of symptomatic trees collected at different geographic locations were analysed by a polymerase chain reaction (using universal and group-specific primers) and restriction fragment length polymorphism. Phytoplasmas belonging to 16SrIII-B group were detected at almost every location sampled, whereas 16SrXIII-C group phytoplasmas, reported for the first time in Argentina, were only found in two regions sharing similar agro-ecological characteristics (Northeast provinces and Tucumán). Double infections with 16SrIII-B and 16SrXIII-C group phytoplasmas were also recorded. Nucleotide sequencing of the 16S rDNA of three Argentinian 16SrXIII-C group phytoplasma isolates revealed high identity (99.6,99.3%) with the CbY1 isolate reported from Bolivia. [source] Characterization of A New Almond Witches' Broom Phytoplasma in IranJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2006M. Salehi Abstract Almond witches' broom (AlmWB) is a destructive disease in several provinces in Iran. Association of phytoplasma with the disease has been established previously. In the present work two phytoplasmas from Khafr (KAlmWB) and Neyriz (NAlmWB) in the Fars Province were compared by biological and molecular analysis. Both infected bitter almond, wild almond, peach and nectarine but not apple and pear, by grafting. In bitter almond the symptoms induced by KAlmWB consisted of severe proliferation, internode shortening and leaf size reduction. In contrast, NAlmWB caused leaf necrosis, dieback and death. KAlmWB was transmitted to periwinkle and eggplant and from experimentally infected periwinkle to almond by dodder. It was also transmitted from eggplant to eggplant, ornamental eggplant and tomato by grafting. Under similar test conditions, NAlmWB was not transmitted to herbaceous plants by dodder. Phylogenetic analysis of 16S,23S rDNA spacer region (SR) sequences placed both strains in the pigeon pea witches' broom (PPWB) group. However, based on phylogenetic and putative restriction site analyses and sequence homology, NAlmWB was identical with the Lebanese AlmWB phytoplasma, while KAlmWB was closer to the Knautia arvensis phyllody (KAP) agent. Clustering of KAlmWB with KAP was confirmed by analysis of full length 16S rDNA sequence. On the basis of host range, dodder transmission, host range, symptomatology and molecular analyses of 16S rDNA and SR, two different phytoplasmas related to PPWB group were associated with AlmWB disease in Iran. KAlmWB phytoplasma is being reported as a new phytoplasma of AlmWB disease. [source] The Occurrence of Phytoplasmas in Apple Trees Showing Branch TwistingJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2005J. Fránová Abstract Apple trees showing malformation of branches were found at different locations in the Czech Republic. Ultrathin sections of tissues from diseased trees showed the presence of pleomorphic bodies resembling phytoplasma. Nested-polymerase chain reaction (PCR) assays with primers amplifying16S,23S ribosomal RNA (rRNA) sequences specific for phytoplasma and the subsequent restriction fragment length polymorphism (RFLP) analyses allowed to classify the detected phytoplasmas in the aster yellows group, subgroup 16SrI-C in 12 trees, single (11 plants) or mixed with phytoplasma belonging to subgroup 16SrI-B (1 plant). Phytoplasma of apple proliferation group (16SrX-A subgroup) were identified in cv. Mat,ino. Apple tree cv. P,e,tické r,,ové was infected by phytoplasma of the 16SrX-A and 16SrI-B subgroups. No phytoplasmas were detected in asymptomatic apple trees. [source] The Presence of Phytoplasma in Black Currant Infected with the Blackcurrant Reversion DiseaseJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2004Abstract A plant of black currant cv. Karl,tejnský dlouhohrozen showing symptoms of the severe Russian (R) form of the blackcurrant reversion disease (BCRD) was shown to contain phytoplasma bodies measuring 530,750 nm. Phytoplasma infection was confirmed by polymerase chain reaction (PCR) with the universal primer pair R16F1/R16R0, followed by PCR with the primer pair fU5/rU3. A comparison of the sequence of an amplification product of approximately 880 bp with sequences available in the GenBank confirmed the classification of the phytoplasma in the 16SrI (Aster yellows group). This is the first evidence of the natural occurrence of phytoplasma infection in black currant. Blackcurrant reversion virus (BRV), the cause of BCRD, was confirmed in the plant by RT-PCR. A 481 nt cDNA fragment of BRV was sequenced and compared with sequences in GenBank. Rhabdovirus-like particles were also observed in the plant by electron microscopy. [source] Occurrence, Symptom Expression and Characterization of Phytoplasma Associated with Pear Decline Disease in Catalonia (Spain)JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2003M. Garcia-Chapa Abstract A total area of 1500 ha of commercial plots was surveyed to study the extent of pear decline disease and its relative importance in northeastern Spain. A preliminary evaluation indicated that around 7% of the plots had symptoms of the disease. At the same time, pear decline incidence was evaluated in 45 plots, by visual inspection of 500 trees in each plot. In September, the incidence of trees with symptoms ranged from 8 to 59% depending on the cultivar selected. The presence of pear decline (PD) phytoplasma in these plots was confirmed by polymerase chain reaction (PCR) amplification of phytoplasma DNA with universal or group-specific primers. Restriction fragment length polymorphism analyses also showed the presence of a unique phytoplasma strain. The symptom expression of PD disease in different cultivars was evaluated throughout the year. The relationship between the presence of symptoms and detection of PD by PCR in these cultivars was also studied. Results showed that the nested-PCR, using specific primers to detect the DNA from PD phytoplasma, is the most accurate method to identify the total percentage of affected trees. [source] Physiological Performance of Asymptomatic and Yellow Leaf Syndrome-affected Sugarcanes in VenezuelaJOURNAL OF PHYTOPATHOLOGY, Issue 1 2002M. L. IZAGUIRRE-MAYORAL Serological analyses revealed the presence of the sugarcane yellow leaf virus (ScYLV) in asymptomatic (S,) and symptomatic (S+) yellow leaf syndrome-affected sugarcane plants of the cultivars PR.692176, C.323,68, V.64,10, V.71,47, V.75,6, SP.72,2086, SP.72,1210, SP.74,2005, C.323,68, B.80,549 and B.82,363. Tests for the presence of the sugarcane yellows phytoplasma, carried out by Dr P. Jones (IACR-Rothamsted), gave negative results in all cultivars. Physiological analyses were performed in the top visible dewlap (TVD) leaf of S, and S+ plants of the cultivar PR.692176. All plants were at the second ratoon and flowering. When compared with S, plants, the S+ plants showed: (a) a marked reduction in the area of the leaf and internodes; (b) a high accumulation of total reducing sugars (TRS), glucans and ,-amino-N in the leaf blade and of TRS in the corresponding leaf sheath; (c) a decrease in the chlorophyll, phosphorus and nitrogen content in the leaf; (d) the disappearance of the leaf diurnal fluctuations in TRS accumulation and export as well as the daily oscillations of TRS and glucans between dawn and dusk; and (e) major ultrastructural alterations in the companion cells of the phloem, including the accumulation of ScYLV particles in the cytoplasm. In S, plants, none of the growth and physiological alterations described above were observed, in spite of the high density of ScYLV particles in the cytoplasm. The location of S, and S+ plants close to each other without a discernible pattern of distribution in plots subjected to optimal irrigation and fertilization rule out the possibility that environmental conditions underlay the appearance of symptoms. In plots under severe drought for 3 months, however, all S, plants become S+. Symptom expression did not affect the acid phosphatase activity in the rhizosphere of S+ plants. [source] Detection of Phytoplasma Infection in Rose, with Degeneration SymptomsJOURNAL OF PHYTOPATHOLOGY, Issue 1 2001M. Kami In 1998 a severe disease was observed on rose cvs. ,Patina', ,Papillon' and ,Mercedes' cultivated in a commercial greenhouse in Poland. The symptoms included stunted growth, bud proliferation, leaf malformation and deficiency of flower buds. Sporadically some plants yielded flower buds transformed into big-bud structures and degenerated flowers. The presence of phytoplasma in roses with severe symptoms as well as in recovered plants and Catharanthus roseus experimentally infected by grafting and via dodder was demonstrated by nested polymerase chain reaction assay with primers pair R16F2/R2 or R16F1/R0 and R16(I)F1/R1 amplifying phytoplasma 16S rDNA fragment. The polymerase chain reaction products (1.1 kb) used for restriction fragment length polymorphism analysis after digestion with endonuclease enzymes AluI and MseI produced the same restriction profiles for all samples. The restriction profiles of phytoplasma DNA from these plants corresponded to those of an aster yellows phytoplasma reference strain. Electron microscope examination of the ultra-thin sections of the stem showed wall thickenings of many sieve tubes of the diseased roses and single phytoplasma cells within a sieve element of the phloem of experimentally infected periwinkles. This paper is the first report on aster yellows phytoplasma in rose identified at a molecular level. Detektion einer Phytoplasma-Infektion bei Rosen mit Degenerationserscheinungen Im Jahr 1998 wurde eine schwere Krankheit bei Rosen der Sorten ,Patina', ,Papillon' und ,Mercedes' festgestellt, die in einem polnischen Gewächshaus für kommerzielle Zwecke kultiviert wurden. Zu den Symptomen gehörten Kümmerwuchs, durchwachsene Knospen, Blattmißbildungen und ein Mangel an Blütenknospen. Einige wenige Pflanzen trugen übergroße Blütenknospen, die degenerierte Blüten hervorbrachten. Die Anwesenheit von Phytoplasmen in Rosen mit starken Symptomen, in erholten Pflanzen und in Catharanthus roseus, der durch Pfropfen und durch Teufelszwirn (Cuscuta) experimentell infiziert worden war, wurde mittels einer genesteten Polymerase-Kettenreaktion mit den Primerpaaren R16F2/R2 oder R16F1/R0 und R16(1)F1/R1 zur Amplifikation des Phytoplasma-16S rDNA-Fragments demonstriert. Die für die Analyse der Restriktionsfragmentlängenpolymorphismen nach Verdau mit den Endonucleasen AluI und MseI verwendeten PCR-Produkte (1,1 kb) produzierten bei allen Proben die gleichen Restriktionsprofile. Die Restriktionsprofile der Phytoplasma-DNA aus diesen Pflanzen entsprachen denjenigen eines Typenstamms eines Asternvergilbung auslösenden Phytoplasmas. Elektronenmikroskopische Untersuchungen ultradünner Schnitte des Stamms zeigten Wandverdickungen bei zahlreichen Siebröhren der erkrankten Rosen und einzelne Phytoplasmazellen innerhalb eines Siebelements des Phloems experimentell infizierter Immergrün-Pflanzen. Dies ist der erste Bericht über ein auf molekularer Ebene identifiziertes Asternvergilbungs-Phytoplasma bei Rosen. [source] Presence of two glycolytic gene clusters in a severe pathogenic line of Candidatus Phytoplasma asterisMOLECULAR PLANT PATHOLOGY, Issue 4 2007KENRO OSHIMA SUMMARY Phytoplasmas are plant-pathogenic bacteria that are associated with numerous plant diseases. We have previously reported the complete genomic sequence of Candidatus Phytoplasma asteris, OY strain, OY-M line, which causes mild symptoms. The phytoplasma genome lacks several important metabolic genes, implying that the consumption of metabolites by phytoplasmas in plants may cause disease symptoms. Here we show that the approximately 30-kb region including the glycolytic genes was tandemly duplicated in the genome of OY-W phytoplasma, which causes severe symptoms. Almost duplicated genes became pseudogenes by frameshift and stop-codon mutations, probably because of their functional redundancy. However, five kinds of genes, including two glycolytic genes, remained full-length ORFs, suggesting that it is advantageous for the phytoplasma to retain these genes in its lifestyle. In particular, 6-phosphofructokinase is known as a rate-limiting enzyme of glycolysis, implying that the different number of glycolytic genes between OY-W and OY-M may influence their respective glycolysis activities. We previously reported that the phytoplasma population of OY-W was higher than that of OY-M in their infected plants. Taking this result into account, the higher consumption of the carbon source may affect the growth rate of phytoplasmas and also may directly or indirectly cause more severe symptoms. [source] A phytoplasma associated with ,amachamiento' disease of dry common bean in Costa RicaPLANT PATHOLOGY, Issue 2 2010L. Moreira No abstract is available for this article. [source] Flavescence dorée phytoplasma affecting grapevine (Vitis vinifera) newly reported in PortugalPLANT PATHOLOGY, Issue 2 2010E. De Sousa No abstract is available for this article. [source] Occurrence of an aster yellows (16SrI) group phytoplasma associated with a leaf roll disease of shinyleaf yellowhorn in ChinaPLANT PATHOLOGY, Issue 4 2009C. P. Zhang No abstract is available for this article. [source] First report on the association of a 16SrII phytoplasma with sesame phyllody in PakistanPLANT PATHOLOGY, Issue 4 2008K. P. Akhtar No abstract is available for this article. [source] Occurrence of a 16SrII group phytoplasma associated with crotalaria witches' broom in Hainan, ChinaPLANT PATHOLOGY, Issue 2 2008Z. H. Wang No abstract is available for this article. [source] A phytoplasma associated with witches' broom disease of Tabebuia pentaphylla in BrazilPLANT PATHOLOGY, Issue 2 2008R. G. Mafia No abstract is available for this article. [source] Introductions of non-native plant pathogens into Great Britain, 1970,2004PLANT PATHOLOGY, Issue 5 2007D. R. Jones An analysis of records of plant pathogens first identified in Great Britain from 1970 to 2004 (inclusive) was undertaken to determine the numbers of new species that have become established over time. Results show that the numbers of newly recorded pathogens have not varied significantly. Of the 234 pathogens recorded for the first time between 1970 and 2004, 157 were fungi, 27 were oomycetes, 26 were viruses, 23 were bacteria, and one was a phytoplasma. Approximately 53% of pathogens were found on ornamental crops, 16% on horticultural crops, 15% on wild native species, 12% on agricultural crops, 2% on pasture plants and 2% on exotic forestry tree species. Where the origin of introductions was known or strongly suspected, 47% came from the Netherlands. About 38% of newly recorded pathogens with information on the location of first record were discovered in the South East region of England. Plant Pathologists regarded 19% of all new pathogens as important because of actual or potential economic/environmental losses. The results indicate that the numbers of new or important pathogens establishing in recent years are not increasing and that most new findings are associated with ornamental plants. [source] Use of terminal restriction fragment length polymorphism (T-RFLP) for identification of phytoplasmas in plantsPLANT PATHOLOGY, Issue 3 2007J. Hodgetts A terminal restriction fragment analysis (T-RFLP) technique was developed for the simple and rapid detection and diagnosis of phytoplasmas in plants. The selected primers amplified part of the 23S rRNA gene to provide improved resolution between the taxonomic groups compared to conventional restriction enzyme analysis of the 16S rRNA. Using the restriction enzymes Bsh12361 and MseI on the PCR products, and fragment analysis in the range 68,640 bp, the technique was tested on 37 isolates from 10 of the 16Sr groups. Distinct and unambiguous T-RFLP profiles were produced for nine of the 10 taxonomic groups, such that almost all isolates within a group shared the same profile and could be distinguished from isolates in other groups. The technique also identified the presence of mixtures of phytoplasmas from different groups in samples. Furthermore, the primers were devised to amplify a terminal restriction fragment (TRF) product of a specific defined size (461 bp) from the host plant chloroplast DNA, so that there was a built-in internal control in the procedure to show that the absence of a phytoplasma peak in a sample was the result of no detectable phytoplasma being present, not the result of PCR inhibition. This method offers the possibility of simultaneously detecting and providing a taxonomic grouping for phytoplasmas in test samples using a single PCR reaction. [source] First report of a 16SrII (,Candidatus Phytoplasma aurantifolia') group phytoplasma associated with a bunchy-top disease of papaya in CubaPLANT PATHOLOGY, Issue 6 2006Y. Arocha No abstract is available for this article. [source] Basil little leaf: a new disease associated with a phytoplasma of the 16SrI (Aster Yellows) group in CubaPLANT PATHOLOGY, Issue 6 2006Y. Arocha No abstract is available for this article. [source] ,Brotes grandes' (big bud) of potato: a new disease associated with a 16SrI-B subgroup phytoplasma in BoliviaPLANT PATHOLOGY, Issue 2 2005P. Jones No abstract is available for this article. [source] | |||||||||||||||||||||||||