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1.
Plant Dis ; 97(8): 1122, 2013 Aug.
Article in English | MEDLINE | ID: mdl-30722469

ABSTRACT

Rose is the top selling cut flower in New Zealand and is the most popular garden plant in the world. Several virus-like diseases have been described in roses, but the causal agents for many remain unknown. Most of the described viruses infecting rose belong to the genera Ilarvirus and Nepovirus. Only recently, a number of new viruses have been or are in the process of being characterized (1,2,3,4). In January 2011, 10 rose samples showing virus-like symptoms were collected from the Wanganui region on the North Island of New Zealand. Total nucleic acid was extracted from these samples using an InviMag Plant DNA Mini Kit (Invitek GmbH, Berlin, Germany) and a KingFisher mL workstation (Thermo Scientific, Waltham, MA). PCR and reverse transcription (RT)-PCR was conducted using specific primers for Arabis mosaic virus (ArMV), Cherry leaf roll virus, Prunus necrotic ringspot virus (PNRSV), Rosa rugosa leaf distortion virus, Rose spring dwarf associated virus, Rose yellow leaf virus, Rose yellow mosaic virus, Rose yellow vein virus (RYVV), and Strawberry latent ringspot virus. Samples were also tested using generic primers for carlavirus, potexvirus, potyvirus, tombusvirus, and phytoplasmas. Two samples (cvs. Pauls Himalayan Musk and Bloomfield) were positive for ArMV, four samples (cvs. Leda, Rosa Mundi, Charles de Mills, and Indica Major) were positive for PNRSV, and two samples (cvs. Leda and Zephirine Drouhin) were positive for RYVV. Samples were negative for all other tested viruses and phytoplasmas. RYVV was detected using two sets of primers (D. Mollov, personal communication) designed to amplify fragments of estimated sizes of 797 bp and 684 bp of the movement protein (MP) and coat protein (CP) genes of RYVV, respectively. RYVV amplicons were sequenced directly (GenBank Accession Nos. JX887423 to JX887426). A BLASTn search of the MP and CP fragments showed the highest nucleotide identity of 98% and 96 to 97%, respectively, with the type isolate of RYVV (JX028536). RYVV has been reported as the causal agent of a vein yellowing disease in rose (2). Symptoms observed in the 'Leda' sample infected with PNRSV and RYVV (vein yellowing and chlorotic mottle in the apex of leaves) were not typical of PNRSV, so they may be caused by RYVV. Symptoms in samples of cv. Zephirine Drouhin (curling of leaves and mottle), observed in both RYVV-positive and -negative samples, may not be associated with RYVV infection. This suggests that vein yellowing may be influenced by cultivar. RYVV has been reported in several rose cultivars, but only in the United States (2). To the best of our knowledge, this is the first report of RYVV infecting rose in New Zealand, where it is likely that the virus has been present for some time. The virus may have a much wider geographical distribution than that reported as the virus was only recently characterized (3). References: (1) B. Lockhart et al. Page 31 in: Program and Abstracts of The 12th International Symposium on Virus Diseases of Ornamental Plants, 2008. (2) D. Mollov et al. Phytopathology 99:S87, 2009. (3) D. Mollov et al. Arch Virol. 158:877, 2012. (4) N. Salem et al. Plant Dis. 92:508, 2008.

3.
Plant Dis ; 95(5): 617, 2011 May.
Article in English | MEDLINE | ID: mdl-30731974

ABSTRACT

In February 2009, grapevines (Vitis vinifera) in a commercial vineyard in Auckland were showing shortened, spindly canes with tiny leaves. Approximately 10% of the vines were affected. An RNeasy Plant Mini Kit (Qiagen, Valencia, CA) was used to isolate total RNA from leaves collected from six symptomatic (cvs. BAC0022A and Syrah) and eight symptomless vines (cvs. BAC0022A, Syrah, and Chardonnay). RNA was tested by reverse transcription-PCR for the presence of Australian grapevine viroid, Citrus exocortis viroid, Grapevine yellow speckle viroid 1 (GYSVd-1), Grapevine yellow speckle viroid 2, and Hop stunt viroid (HSVd). Four of the six symptomatic and all the symptomless vines tested positive for GYSVd-1 using primers 5'-TGTGGTTCCTGTGGTTTCAC-3' and 5'-ACCACAAGCAAGAAGATCCG-3', which amplify the complete genome (368 bp), and published primers PBCVd100C/194H (3), which amplify a 220-bp region of the genome. Amplicons from each PCR were transformed into a pCR 4-TOPO vector (Invitrogen, Carlsbad, CA), cloned, and sequenced. Sequence from both PCRs aligned identically to generate a consensus sequence (GenBank Accession No. HQ447056), which showed 99% nt identity to GYSVd-1 (GenBank No. X87906) by BLASTN analysis. All symptomatic and symptomless vines also tested positive for HSVd using primers C/H-HSVd (4) and HSVd-C60/H79 (1), which amplify the complete genome (298 bp). Amplicons from each isolate were cloned and sequenced. Sequence from both PCRs were aligned. Clones from all isolates, with the exception of one, aligned identically to create a consensus sequence (GenBank No. HQ447057) that showed 99% nt identity to Chinese HSVd isolates from grapevine (GenBank Nos. DQ371436-59) by BLASTN analysis. Sequence from the remaining isolate (GenBank No. HQ447056) was identical to a German Riesling grape isolate of HSVd (GenBank No. X06873). The presence of each viroid was further confirmed in PCR-positive plants by dot-blot hybridization with digoxigenin-labeled synthetic ssRNA probes specific to the full-length genomes of GYSVd-1 and HSVd (S. Harper and L. Ward, unpublished data). To our knowledge, this is the first report of GYSVd-1 and HSVd in V. vinifera in New Zealand. Since both viroids were detected in symptomatic and symptomless plants, the symptoms observed in the vineyard cannot be attributed to viroid infection. Symptoms described for GYSVd-1 include leaf spots and flecks, but no disease symptoms have been reported in grapes as a result of HSVd (2). Viruses found in the vines include Grapevine leaf roll virus-3, Grapevine viruses A and B, and Rupestris stem pitting associated virus, but these are not thought to be the cause of the symptoms. Two sequence types of HSVd were found, suggesting at least two separate introductions of HSVd into the vineyard. The vineyard is more than 40 years old so both viroids may have been present for some years. Export of wine from New Zealand was worth 1 billion dollars in 2009, so there is potential for these viroids to have an economic impact if symptoms are expressed. HSVd has been reported from China, Europe, Japan, Middle East, Pakistan, and the United States. GYSVd-1 has been reported from Australia, China, East Mediterranean, Europe, Japan, and the United States. References: (1) A. Hadidi et al. Acta Hortic. 309:339, 1992. (2) A. Hadidi et al., eds. Viroids. CSIRO Publishing, Collingwood, Australia, 2003. (3) R. Nakaune and M. Nakano. J. Virol. Methods 134:244, 2006. (4) A. M. Shamoul et al. J. Virol. Methods 105:115, 2002.

4.
Phytopathology ; 100(12): 1282-8, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20731533

ABSTRACT

Xylella fastidiosa is a regulated plant pathogen in many parts of the world. To increase diagnostic capability of X. fastidiosa in the field, a loop-mediated isothermal amplification (LAMP) and real-time polymerase chain reaction (PCR) assay were developed to the rimM gene of X. fastidiosa and evaluated for specificity and sensitivity. Both assays were more robust than existing published assays for detection of X. fastidiosa when screened against 20 isolates representing the four major subgroups of the bacterium from a range of host species. No cross-reaction was observed with DNA from healthy hosts or other bacterial species. The LAMP and real-time assays could detect 250 and 10 copies of the rimM gene, respectively, and real-time sensitivity was comparable with an existing published real-time PCR assay. Hydroxynapthol blue was evaluated as an endpoint detection method for LAMP. When at least 500 copies of target template were present, there was a noticeable color change indicating the presence of the bacterium. Techniques suitable for DNA extraction from plant tissue in situ were compared with a standard silica-column-based laboratory extraction method. A portable PickPen and magnetic bead system could be used to successfully extract DNA from infected tissue and could be used in conjunction with LAMP in the field.


Subject(s)
Plant Diseases/microbiology , Xylella/genetics , Base Sequence , DNA Primers , Ecosystem , Gene Amplification , Open Reading Frames/genetics , Plant Diseases/genetics , Polymerase Chain Reaction/methods , Quercus/microbiology , Reverse Transcriptase Polymerase Chain Reaction , Vitis/microbiology , Xylella/isolation & purification
5.
Plant Dis ; 94(4): 479, 2010 Apr.
Article in English | MEDLINE | ID: mdl-30754502

ABSTRACT

In February 2009, 10 cape gooseberry plants (Physalis peruviana) grown from seed on a domestic property in Christchurch, New Zealand, showed severe leaf distortion, fasciation and etiolation of growing tips, and weak flowering. Symptoms were first observed in the emerging seedlings. No virus particles were observed in sap from infected plants with the electron microscope. Total RNA was isolated from leaves of the 10 plants with a Qiagen RNeasy Plant Mini Kit (Valencia, CA). All 10 plants tested positive for Potato spindle tuber viroid (PSTVd) by real-time reverse transcription (RT)-PCR (1) and by RT-PCR with PSTVd-specific primers (3) and generic pospiviroid primers (4). For both conventional PCRs, the expected 359-bp amplicons were sequenced directly and sequences were aligned together to create a consensus sequence (GenBank Accession No. FJ797614). BLASTn analysis showed 98% nucleotide identity to PSTVd (EU862231, DQ308556, X17268, and AY532801-AY532804). Sap from one of the infected plants was mechanically inoculated onto healthy P. peruviana, Solanum lycopersicum 'Rutgers', Chenopodium amaranticolor, C. quinoa, Cucumis sativum 'Crystal Apple', Gomphrena globosa, Nicotiana benthamiana, N. clevelandii, N. occidentalis '37B', N. tabacum 'WB', N. sylvestris, and Phaseolus vulgaris 'Prince'. After 4 weeks, the leaves of the 'Rutgers' tomato plants were showing severe distortion, purpling, and necrosis of mid-veins and P. peruviana plants were showing distortion of newly emerging apical leaves. Healthy control P. peruviana were asymptomatic. Symptoms appeared milder than that observed in the original P. peruviana plants, but this may be related to different environmental conditions or age or growth stage of the plants when inoculated. All other indicator plants were symptomless, but along with P. peruviana, tested positive for PSTVd by real-time RT-PCR (1). The presence of PSTVd was further confirmed in one original symptomatic and the mechanically inoculated P. peruviana plants and in the indicator plants by dot-blot hybridization with a digoxygenin-labeled synthetic ssRNA probe specific to the full-length PSTVd genome. PSTVd has been reported in New Zealand previously in commercial glasshouse crops of tomatoes and peppers (2), but was eradicated and so remains a regulated pest. The plants were grown from seeds imported from Germany and it is possible that the infection was seedborne. PSTVd was reported in young cape gooseberry seedlings in Germany and Turkey but the infection was asymptomatic (5). Symptoms were associated with the PSTVd-infected cape gooseberry in New Zealand. To our knowledge, this is the first report of the viroid in domestically grown plants in New Zealand, and only the second report of PSTVd in cape gooseberry worldwide. Our findings suggest that this species is an emerging host for PSTVd and that dissemination of seed may provide a pathway for international movement of the viroid. References: (1) N. Boonham et al. J. Virol. Methods 116:139, 2004. (2) B. S. M. Lebas et al. Australas. Plant Pathol. 34:129, 2005. (3) A. M. Shamoul et al. Can. J. Plant Pathol. 19:89, 1997. (4) J. T. H. Verhoeven et al. Eur. J. Plant Pathol. 110:823, 2004. (5) J. T. H. Verhoeven et al. Plant Dis. 93:316, 2009.

6.
Plant Dis ; 93(9): 969, 2009 Sep.
Article in English | MEDLINE | ID: mdl-30754545

ABSTRACT

In January of 2009, potato plants (Solanum tuberosum) from a commercial crop in the Waikato Region, New Zealand were observed to have symptoms of upward rolling and purpling of the leaves. The symptoms appeared similar to those of "zebra chip", a disorder of potato recently found to be associated with 'Candidatus Liberibacter solanacearum' in New Zealand and the United States (4). Total DNA from the leaf midveins and tubers from one of the symptomatic plants was separately extracted with an InviMag Plant DNA Mini Kit (Invitek GmbH, Berlin, Germany) and a KingFisher mL workstation (Thermo Scientific, Waltham, MA). DNA extracted from leaf midveins and tubers tested negative for 'Ca. L. solanacearum' by nested-PCR using primer pair OA2/OI2c (4) followed by Lib16S01F/Lib16S01R (5'-TTCTACGGGATAACGCACGG-3' and 5'-CGTCAGTATCAGGCCAGTGAG-3'), which amplifies a 580-bp region of the 16S rRNA gene. However, DNA extracted from the tuber tissue tested positive for phytoplasma by TaqMan real-time PCR (3). No phytoplasma was detected in the DNA extracted from leaf tissue. The 16S rRNA gene, 16S-23S rRNA intergenic spacer region, and part of the 23S rRNA gene of the phytoplasma were amplified with primers P1/P7 (1). The PCR product was cloned into the pCR 4-TOPO vector (Invitrogen, Carlsbad, CA) and sequenced (GenBank Accession No. FJ943262). BLAST analysis showed 100% identity to 'Ca. Phytoplasma australiense' (16SrXII, Stolbur group). A fragment of approximately 850-bp of the Tuf gene was also amplified (2) and sequenced directly (GenBank Accession No. FJ943263). BLAST analysis showed 100% identity to Tuf gene variant IX of 'Ca. P. australiense' (2). An additional 14 plants showing similar leaf symptoms and also production of aerial tubers were collected from seven different potato fields from the Auckland and Waikato regions. Total DNA from the leaf midveins, stem, and tubers were separately extracted from each of the plants. The samples were tested for phytoplasma by nested-PCR using primer pair R16F2/R16R2, followed by NGF/NGR (1), and tested for 'Ca. L. solanacearum' by nested-PCR as described above. Seven plants tested positive only for phytoplasma, three tested positive for only 'Ca. L. solanacearum', and four plants tested positive for both pathogens. The pathogens were most commonly detected in samples extracted from the stem with 9 and 5 of the 14 samples testing positive for phytoplasma and liberibacter, respectively. Six of each of the leaf and tuber samples tested positive for phytoplasma. Liberibacter was detected in one of the leaf samples and in four of the tuber samples. 'Ca. P. australiense' has only been reported from New Zealand and Australia. The only other known hosts of 'Ca. P. australiense' in New Zealand are strawberry and native plants belonging to the genera Cordyline, Coprosma, and Phormium (2). In Australia, 'Ca. P. australiense' is associated with Australian grapevine yellows and Papaya dieback (2). To our knowledge, this is the first report of 'Ca. P. australiense' infecting potato as well as the first report of phytoplasma and 'Ca. L. solanacearum' mixed infections in potato. References: (1) M. T. Andersen et al. Plant Pathol. 47:188, 1998. (2) M. T. Andersen et al. Phytopathology 96:838, 2006. (3) N. M. Christensen et al. Mol. Plant Microbe Interact. 17:1175, 2004. (4) L. W. Liefting et al. Plant Dis. 93:208, 2009.

7.
Plant Dis ; 93(9): 964, 2009 Sep.
Article in English | MEDLINE | ID: mdl-30754563

ABSTRACT

In September 2008, Narcissus plants originating from commercial nurseries in Taranaki (TK) in New Zealand's North Island and Canterbury (CB) in the South Island were received showing leaf mottling, flower distortion, and color break. The CB plant also showed stunting. Filamentous virus particles (700 to 900 nm long) were seen in crude sap of both plants with a transmission electron microscope. Total RNA was isolated from the leaves of both plants with an RNeasy Plant Mini Kit (Qiagen, Chatsworth, CA), and cDNA was synthesized by Superscript III (Invitrogen, Carlsbad, CA). cDNA was used in PCR to test for viruses in the following genera: Allexivirus, Carlavirus, Cucumovirus, Nepovirus A and B, Potyvirus, Potexvirus, Tospovirus, and Tobravirus. Both plants tested positive for potyvirus using generic potyvirus primers (3). Amplicons from both plants were directly sequenced. The forward and reverse sequence from the CB plant matched sequences in the GenBank database for Narcissus late season yellows virus (NLSYV) and Narcissus degeneration virus (NDV), respectively. The potyvirus amplicon from the CB plant was cloned and sequenced. Sequence from independent clones was obtained for NLYSV only (No. FJ546721), and this sequence showed 97% nucleotide identity to NLYSV No. EU887015. The CB plant was tested with a second set of generic potyvirus primers using forward (PV1SP6) (2) and reverse primers (U335) (1). BLASTN analysis of the sequence obtained from independent clones (No. FJ543718) matched sequence for NDV only (97% nucleotide identity to No. AM182028). BLASTN analysis of the potyvirus obtained for the TK plant (No. FJ546720) showed 97% nucleotide identity to NLSYV (No. EU887015). The TK plant also tested positive for a carlavirus using commercial primers (Agdia, Elkhart, IN) and unpublished generic carlavirus primers (A. Blowers, personal communication). Amplicons from both PCRs were cloned and sequenced. BLASTN analysis of both sequences (Nos. FJ546719 and GQ205442) showed 94% nucleotide identity to Narcissus symptomless virus (NSV) No. AM182569. Both plants were also tested for NLSYV, Narcissus virus Q, Narcissus latent virus, and Narcissus yellow stripe virus by indirect ELISA (Neogen, Lansing, MI). Results confirmed the presence of NLSYV in both plants but the plants were negative for the other viruses. NLSYV has been detected previously from Narcissus pseudonarcissus L. (daffodil) (D. Hunter, personal communication); however, to our knowledge, this is the first official report of NDV, NLSYV, and NSV in New Zealand. Since both plants tested negative for several other viruses by PCR and ELISA, this would suggest that the symptoms observed may have been caused by NSV, NLSYV, NDV, or as a result of a mixed infection. However, symptoms were not confirmed using Koch's postulate. NSV has been reported in the literature as symptomless. NLYSV has been reported to be a possible cause of leaf chlorosis and striping and NDV has been associated with chlorotic leaf striping in N. tazetta plants (4). Since Narcissus is an important flower crop for domestic production in New Zealand, the reduction in flower quality observed when these viruses are present may be of economic significance in commercial nurseries. References: (1) S. A. Langeveld et al. J. Gen. Virol. 72:1531, 1991. (2) A. M. Mackenzie et al. Arch Virol. 143:903, 1998. (3) V. Marie-Jeanne et al. J. Phytopathol. 148:141, 2000. (4) W. P. Mowat et al. Ann. Appl. Biol. 113:531, 1988.

8.
Plant Dis ; 93(4): 427, 2009 Apr.
Article in English | MEDLINE | ID: mdl-30764237

ABSTRACT

In New Zealand, sweet potato (Ipomoea batatas) is a crop of cultural importance and an important food source; it is grown mainly in the districts of Kaipara, Auckland, and the Bay of Plenty in the North Island. In January of 2008, virus symptoms that included chlorotic spots, ring spots, and mottling were observed on the leaves of commercial sweet potato crops (cvs. Beauregard, Owairaka Red, and Toka Toka Gold) growing in the three main production areas. A survey was done to determine the extent of virus infection in these crops. Fifty to one hundred leaves were collected randomly from each of 26 different fields. Leaves from each field were bulked into groups of 10, giving a total of 173 composite samples. All samples tested negative for Cucumber mosaic virus, C-6 virus, Sweet potato caulimo-like virus, Sweet potato chlorotic fleck virus, Sweet potato chlorotic stunt virus (SPCSV), Sweet potato latent virus, and Sweet potato mild specking virus by nitrocellulose membrane enzyme-linked immunosorbent assays (International Potato Center-CIP, Lima, Peru). Total nucleic acid was extracted from all 173 composite samples and used in real-time PCR assays specific for Sweet potato leaf curl virus (SPLCV) and real-time reverse transcription (RT)-PCR specific for SPCSV, Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), and Sweet potato virus 2 (SPV2; synonym Sweet potato virus Y) (1). No samples were positive for SPLCV or SPCSV, but 107 and 138 samples tested positive for SPFMV and SPVG, respectively. SPFMV and SPVG have been reported previously in New Zealand (2,3). Sixty four samples from 16 different fields tested positive for SPV2. Of the 64 samples, 52 were also infected with SPVG and SPFMV, and 10 were co-infected with SPVG but not SPFMV; no samples were co-infected with SPV2 and SPFMV when SPVG was absent. From a representative SPV2 positive sample, the 70-bp amplicon obtained by the real-time RT-PCR primers was cloned and sequenced A BLAST search showed 100% nucleotide sequence identity with SPV2 (GenBank Accession Nos. AM050887 and AY178992). Subsequently, primers (V2-F1c: 5'-AGAACAGGACAAACTCAACC-3'; V2-R1: 5'-TAATCACCCTTCACACCTTC-3') were designed to amplify an approximately 434-bp fragment within the SPV2 coat protein gene. One-step RT-PCR was done on four of the SPV2 positive samples and amplicons of the expected size were sequenced directly (GenBank Accession No. FJ461774). Sequence comparison showed 99% nucleotide sequence identity with SPV2 (GenBank Accession Nos. AM050886, AM050887, AY178992, and EF577437). SPV2 is a member of the genus Potyvirus but the virus has not been fully characterized. It is known that single-potyvirus infections cause mild or no symptoms in sweet potato, and consequently, no significant yield reduction is observed generally. However, co-infection with other viruses such as SPCSV produces a synergistic effect and more severe disease symptoms (4). To our knowledge, this is the first report of SPV2 infecting sweet potato in New Zealand. References: (1) C. D. Kokinos and C. A. Clark. Plant Dis. 90:783, 2006. (2) M. N. Pearson et al. Australas. Plant Pathol. 35:217, 2006. (3) M. Rännäli et al. Plant Dis. 92:1313, 2008. (4) M. Untiveros et al. Plant Dis. 91:669, 2007.

9.
Plant Dis ; 92(11): 1588, 2008 Nov.
Article in English | MEDLINE | ID: mdl-30764458

ABSTRACT

A new 'Candidatus Liberibacter' species was recently identified in tomato, capsicum, and potato in New Zealand. The tomato/potato psyllid, Bactericera cockerelli, is thought to be the vector of this species of liberibacter. During studies to determine additional host plants of the pathogen, leaves of Solanum betaceum (tamarillo, also known as tree tomato) and leaves and stems of Physalis peruviana (cape gooseberry) were collected from a home garden in South Auckland, New Zealand in July of 2008. These plants were not showing any obvious disease symptoms. They were located close to a commercial glasshouse site containing known liberibacter-infected tomatoes, and many psyllids were observed on the tamarillo tree over the summer and until late autumn. Total DNA was extracted from four tamarillo and two cape gooseberry samples with a DNeasy Plant Mini Kit (Qiagen, Valencia, CA). Samples from tamarillo that were used for the extraction were taken from the midveins of old and young leaves and from young petioles. For cape gooseberry, samples were from the leaf midveins and the stems. The samples were tested by PCR using primers OA2 (GenBank Accession No. EU834130) and OI2c (1). These primers amplify a 1,160-bp fragment of the 16S rRNA gene of the new liberibacter species. Amplicons of the expected size were obtained from all four tamarillo samples, with no amplification from negative control tamarillo plants grown from seed in an insect-proof glasshouse. Almost the entire length of the 16S rRNA gene was amplified using primer pairs fD2 (3)/OI2c and OA2/rP1 (3), and the 16S-23S rRNA intergenic spacer was amplified with primer pair OI2/23S1 (2). These amplicons, along with that from the OA2/OI2c primer pair, were directly sequenced, and overlapping fragments were assembled using the SeqMan software of the LaserGene package (DNASTAR, Inc., Madison, WI) (GenBank Accession No. EU935004). A 650-bp fragment of the ß operon was also amplified and sequenced directly (GenBank Accession No. EU935005). BLAST analysis showed 100% nt identity to the liberibacter of tomato (GenBank Accession Nos. EU834130 and EU834131) and potato (GenBank Accession Nos. EU849020 and EU919514). The two cape gooseberry samples produced amplicons of the expected size with the 16S rRNA and ß operon primers and the origin of the fragments were confirmed by direct sequencing with BLAST analysis showing 100% nt identity to isolates from tomato, potato, and tamarillo. To determine the distribution of disease, 53 samples of 10 leaves each (representing two leaves from five plants) were collected randomly from a commercial tamarillo crop in South Auckland. Small sections of the midveins were removed from each of the 10 leaves, bulked, and DNA was extracted as described above. The samples were tested by PCR using primer pair OA2/OI2c. Amplicons of the expected size were obtained from 2 of the 53 samples. To our knowledge, this is the first report of a liberibacter in tamarillo and cape gooseberry. It is unknown if the liberibacter induces symptoms in these species or if they act as symptomless reservoirs of the pathogen. The infected plants will be observed for symptom development over the course of a growing season. References: (1) S. Jagoueix et al. Mol. Cell. Probes 10:43, 1996. (2) S. Jagoueix et al. Int. J. Syst. Bacteriol. 47:224, 1997. (3) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.

10.
Plant Dis ; 92(7): 1134, 2008 Jul.
Article in English | MEDLINE | ID: mdl-30769512

ABSTRACT

Wisteria vein mosaic virus (WVMV) is a member of the Potyvirus genus. The virus has been reported in Wisteria spp. in Australia, China, the United States, and a number of European countries (2). In 2006, several W. sinensis plants with mottling and mosaic symptoms were observed in a commercial plant nursery in Whenuapai, north of Auckland, New Zealand. These plants had been propagated from a nursery in the New Plymouth area of New Zealand. Sap from the symptomatic Wisteria plants was examined with an electron microscope and elongated and flexuous potyvirus-like particles approximately 750 nm long were observed. RNA was extracted from the symptomatic plants with a Qiagen RNeasy Plant Mini Kit (Doncaster, Australia). The RNA was initially tested using general potyvirus primers, PV1/SP6 (4) and U335 (3), with the cycling conditions of 94°C for 5 min followed by 40 cycles of 94°C for 45 s, 50°C for 45 s, 72°C for 90 s, and a final extension of 72°C for 7 min. The polymerase chain reaction (PCR) product (695 bp) was directly sequenced (GenBank Accession No. EU580146) and a BLAST search in GenBank showed 98% nucleotide identity with WVMV (GenBank Accession no. AF484549). The RNA was then tested using WVMV-specific primers, WVMVF1 and WVMVR1, and the published cycling conditions (2). PCR amplicons of 701 bp were obtained. PCR products were directly sequenced (GenBank Accession No. EU308592), and a BLAST search in GenBank showed 98% nucleotide identity with published sequences of WVMV (GenBank Accession Nos. AF484549 and AY656816). In addition, RNA was extracted from the original isolate of WVMV that was reported in the Netherlands (1; supplied by R. van der Vlugt, Plant Research International) and the RNA was amplified using the WVMV-specific primer pair. The sequence obtained from PCR amplicons of the type isolate (GenBank Accession No. EU308593) showed a 98% nucleotide identity with the New Zealand WVMV isolate and with published sequences of WVMV (as shown above). From the symptomatology, particle morphology, and nucleotide sequences, it is concluded that WVMV is present in New Zealand. The distribution of the virus in New Zealand is not known, but the affected plants at the New Plymouth nursery may have been imported into New Zealand as many as 30 years ago. Although WVMV infection can reduce the quality of commercial plants, the disease is not economically significant in New Zealand. References: (1) L. Bos. Neth. J. Plant Pathol. 76:8, 1970. (2) G. R. G. Clover et al. Plant Pathol. 52:92, 2003. (3) S. A. Langeveld et al. J. Gen Virol. 72:1531, 1991. (4) A. M. Mackenzie et al. Arch Virol. 143:903, 1998.

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