Roelofarendsveen, Netherlands


Roelofarendsveen, Netherlands
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Verhoeven J.T.J.,National Plant Protection Organization of the Netherlands | Koenraadt H.M.S.,Naktuinbouw | Westenberg M.,National Plant Protection Organization of the Netherlands | Roenhorst J.W.,National Plant Protection Organization of the Netherlands
Archives of Virology | Year: 2017

Tomato apical stunt viroid (TASVd) has been identified in a 24-year old seed lot of Capsicum annuum produced in Taiwan. It is the first finding of TASVd in this plant species. The isolate could be discriminated from all reported isolates of TASVd based on its nucleotide sequence, which showed only 94.8% identity with the most related genotype of TASVd. This discrimination was substantiated by phylogenetic analysis. Inoculation of a RNA extract of contaminated seeds to healthy pepper plants showed that the infectivity of the viroid had remained over time. Nevertheless, no transmission to seedlings was observed. © 2017, Springer-Verlag Wien.

Verhoeven J.T.J.,National Reference Center | Meekes E.T.M.,Naktuinbouw | Roenhorst J.W.,National Reference Center | Flores R.,Polytechnic University of Valencia | Serra P.,Polytechnic University of Valencia
Journal of General Virology | Year: 2013

A viroid-like RNA has been detected in two asymptomatic dahlia accessions by return and double PAGE. It appeared smaller than Chrysanthemum stunt viroid and Potato spindle tuber viroid, the two members of the genus Pospiviroid, family Pospiviroidae, reported in this ornamental previously. RT-PCR with primers designed for amplifying all pospiviroids produced no amplicons, but RT-PCR with random primers revealed a 342 nt RNA. The sequence of this RNA was confirmed with specific primers, which additionally revealed its presence in many dahlia cultivars. The RNA was named Dahlia latent viroid (DLVd) because it replicates autonomously, but symptomlessly, in dahlia and shares maximum sequence identity with other viroids of less than 56%. Furthermore, DLVd displays characteristic features of the family Pospiviroidae: a predicted rod-like secondary structure of minimum free energy with a central conserved region (CCR), and the ability to form the metastable structures hairpins I and II. Its CCR is identical to that of Hop stunt viroid (HSVd, genus Hostuviroid). However, DLVd: (i) has the terminal conserved region present in members of the genus Pospiviroid, but absent in HSVd, and (ii) lacks the terminal conserved hairpin present in HSVd. Phylogenetic reconstructions indicate that HSVd and Pepper chat fruit viroid (genus Pospiviroid) are the closest relatives of DLVd, but DLVd differs from these viroids in its host range, restricted to dahlia so far. Therefore, while DLVd fulfils the criteria to be a novel species of the family Pospiviroidae, its recombinant origin makes assignment to the genera Pospiviroid or Hostuviroid problematic. © 2013 SGM.

Tjou-Tam-sin N.N.A.,Dutch National Plant Protection Organization NPPO NL | van de Bilt J.L.J.,Dutch National Plant Protection Organization NPPO NL | Westenberg M.,Dutch National Plant Protection Organization NPPO NL | Bergsma-Vlami M.,Dutch National Plant Protection Organization NPPO NL | And 5 more authors.
Plant Disease | Year: 2017

In August 2015, the Dutch National Plant Protection Organization (NPPO-NL) was informed on unusual disease appearances in plants of cut roses (Rosa sp. cv. Armando) in a greenhouse production site. The displayed symptoms were wilting of young shoots and flower stalks, yellowing and early abscission of leaves, stunting, dieback with black necrosis of pruned branches, and in some cases discharge of creamy white slime on cut wounds in the stem. Ambient temperatures in the greenhouses were 25 to 30°C. A bacterial wilt infection caused by Ralstonia solanacearum was suspected. In September 2015, the outcomes from diagnostic investigation by NPPO-NL on rose samples from this greenhouse confirmed that the uncommon symptoms were caused by R. solanacearum. This is, worldwide, the first documented report of R. solanacearum affecting Rosa sp. After this first finding, two other growers producing cut roses (Rosa sp. cv. Sativa and cv. Red Naomi, respectively) reported similar problems in their cultivation. The disease incidence at the three production sites varied from nil up to 50% in some greenhouse compartments. Tracking and tracing to unravel the pathway of infection revealed R. solanacearum infections at two nurseries producing Rosa sp. plants for planting. The primary origin of infection is under investigation but remains unknown at present. The bacterium was isolated from vascular stem tissue of symptomatic plants on semiselective SMSA medium as described in the annexes to Commission Directive 2006/63/EC (EU 2006). Isolates were identified as R. solanacearum by TaqMan real-time PCR (Weller et al. 2000) and immunofluorescence (IF) microscopy (EU 2006) using polyclonal antibodies (Loewe, Germany). Phylotype multiplex PCR (Fegan and Prior 2005) assigned the isolates to phylotype I. Testing the isolates for biovar determination (EU 2006), acid was produced from both the disaccharides and the hexose alcohols. After stem inoculation in tobacco (Nicotiana tabacum cv. White Brurley) for race determination (Buddenhagen et al. 1962) the plants showed wilting within 5 to 10 days. These tests attributed the isolates to biovar 3 and race 1. Pathogenicity of the isolates was tested on tomato plants cv. Moneymaker as described in EU (2006) and on cut rose (Rosa sp. cv. Lucky Red) by infiltrating a cell suspension in 10 mM phosphate buffer (~108 CFU/ml) at the base of a shoot of rooted cuttings. Test plants were incubated at 28/20°C day/night temperature. Rose shoots displayed sectorial wilting, chlorosis, and necrosis of leaves after 10 to 14 days while tomato plants wilted after 4 to 10 days. Completing Koch’s postulates, R. solanacearum was reisolated from the affected tobacco, tomato, and rose plants and reidentified by TaqMan PCR. Amplified fragment length polymorphism (AFLP) analysis (Vos et al. 1995) of R. solanacearum isolates from different ornamentals (including 11 isolates from cut roses) and other crops revealed that the isolates from cut roses cluster in a monophyletic clade, only distantly related to isolates from other crops included in the phylogenetic study. This suggests a single, recent introduction of R. solanacearum into the cut roses cultivation in the Netherlands. © The American Phytopathological Society.

Arens P.,Wageningen UR Plant Breeding | Mansilla C.,Technical University of Madrid | Deinum D.,Naktuinbouw | Cavellini L.,Geves Groupe Detude Et Of Controle Des Varietes Et Des Semences | And 10 more authors.
Theoretical and Applied Genetics | Year: 2010

Molecular markers linked to phenotypically important traits are of great interest especially when traits are difficult and/or costly to be observed. In tomato where a strong focus on resistance breeding has led to the introgression of several resistance genes, resistance traits have become important characteristics in distinctness, uniformity and stability (DUS) testing for Plant Breeders Rights (PBR) applications. Evaluation of disease traits in biological assays is not always straightforward because assays are often influenced by environmental factors, and difficulties in scoring exist. In this study, we describe the development and/or evaluation of molecular marker assays for the Verticillium genes Ve1 and Ve2, the tomato mosaic virusTm1 (linked marker), the tomato mosaic virus Tm2 and Tm22 genes, the Meloidogyne incognita Mi1-2 gene, the Fusarium I (linked marker) and I2 loci, which are obligatory traits in PBR testing. The marker assays were evaluated for their robustness in a ring test and then evaluated in a set of varieties. Although in general, results between biological assays and marker assays gave highly correlated results, marker assays showed an advantage over biological tests in that the results were clearer, i.e., homozygote/heterozygote presence of the resistance gene can be detected and heterogeneity in seed lots can be identified readily. Within the UPOV framework for granting of PBR, the markers have the potential to fulfil the requirements needed for implementation in DUS testing of candidate varieties and could complement or may be an alternative to the pathogenesis tests that are carried out at present. © The Author(s) 2009.

Reid A.,SASA | Hof L.,Naktuinbouw | Felix G.,SASA | Rucker B.,Bundessortenamt | And 6 more authors.
Euphytica | Year: 2011

The European Union Common Catalogue (EUCC) for potato contains over 1000 varieties. Each year member states add varieties to the list after they have undergone Distinctness, Uniformity and Stability (DUS) testing according to international guidelines. A rapid and robust method for variety identification to aid the management and maintenance of existing variety collections and for the screening of new candidate varieties would therefore be a highly useful tool for DUS testing stations. A database containing key morphological characteristics and microsatellite data was constructed for varieties on the 2006 list of the EUCC for potato. Rules for scoring SSR markers in different laboratories were established to allow a harmonized scoring of markers. Almost all varieties (99.5%) were shown to have unique molecular profiles and in pair wise comparisons 99.99% of all variety pairs could be distinguished. This clearly shows the versatility of the markers and database for identifying potato samples. © 2011 Crown Copyright.

Bakker D.,Naktuinbouw | Bruinsma M.,Naktuinbouw | Dekter R.W.,Naktuinbouw | Toonen M.A.J.,Naktuinbouw | And 2 more authors.
EPPO Bulletin | Year: 2015

Worldwide outbreaks of pospiviroids in potato and tomato have increased the need for a reliable test for the detection of pospiviroids in seeds. This study describes the development and validation of a sensitive and fast test for the detection of Potato spindle tuber viroid (PSTVd) and Tomato chlorotic dwarf viroid (TCDVd) in tomato seeds. The test is based on RNA isolation using a commercial kit and is suitable for routine application. The test is able to detect one PSTVd or TCDVd contaminated seed in sub samples of 1000 seeds and results were both repeatable and reproducible. © 2015 OEPP/EPPO.

Meekes E.T.M.,Naktuinbouw | Verbeek M.,Plant Research International
Acta Horticulturae | Year: 2011

Although freesia leaf necrosis disease (FLN) is known in freesia cultures for over forty years, the causal agent(s) is/are still under investigation. In plants with FLN symptoms a virus belonging to the genus Ophiovirus was found; this virus is now known as Freesia sneak virus (FreSV). The virus was mechanically inoculated to and artificially maintained in host plants and purified from these plants. An antiserum was raised and an ELISA-based detection method for FreSV was developed. Mechanical inoculation from indicator plants to freesia seedlings was never successful. Transmission of FreSV using resting spores from Olpidium brassicae was tested to establish whether FreSV is the cause of FLN. The detection of FreSV was evaluated in several surveys using freesias with symptoms (66 lots), without symptoms (98 lots) and by random testing (45 lots). More than 40 different cultivars were surveyed. FreSV was found associated with FLN symptoms, although not in all the freesia lots with FLN-like symptoms. In such lots often Freesia mosaic virus (FreMV) was present and in some lots neither FreSV nor FreMV could be detected. Implications of these findings will be discussed.

Verhoeven J.Th.J.,National Reference Center | Roenhorst J.W.,National Reference Center | Hooftman M.,Naktuinbouw | Meekes E.T.M.,Naktuinbouw | And 2 more authors.
Virus Research | Year: 2015

In symptomless plants of portulaca a potential new pospiviroid was characterized. Analysis by both double and return PAGE showed the presence of a circular RNA. RT-PCR and sequencing revealed a genome of 351 nt with properties characteristic of members of the genus Pospiviroid and with highest sequence identity (circa 80%) with iresine viroid 1 (IrVd-1). The circular RNA from portulaca was shown to replicate independently in its original host, thus showing that it is indeed a viroid. Based on its molecular characteristics, it should be considered a new species. However, since no biological differences have yet been found with its closest relative IrVd-1, the viroid from portulaca does not fulfil all criteria for species demarcation of the ICTV. © 2015 Elsevier B.V..

Verhoeven J.T.J.,National Reference Center | Botermans M.,National Reference Center | Meekes E.T.M.,Naktuinbouw | Roenhorst J.W.,National Reference Center
European Journal of Plant Pathology | Year: 2012

In the Netherlands a survey for pospiviroids was performed in ornamental plants from 2006 up to 2011. Tomato apical stunt viroid (TASVd) was the most frequently found pospiviroid, causing infections in Brugmansia sp., Cestrum sp., Lycianthes rantonnetii, Solanum jasminoides and Streptosolen jamesonii. In addition, five other pospiviroids were detected. In 2011 TASVd also was found in tomato plants in a single greenhouse. The genotype of this isolate was identical to the TASVd genotype found most frequently in ornamentals. This indicates that an ornamental species has been the source of inoculum for the tomato crop. © 2012 KNPV.

Wietsma W.A.,V.O.F. de Keizerskroon | Deinum D.,Naktuinbouw | Teunissen H.A.S.,Naktuinbouw | van den Berg R.G.,Wageningen University
Plant Systematics and Evolution | Year: 2015

Fritillaria sect. Petilium (Fritillaria L., Liliaceae), consists of four species: F.chitralensis, F. eduardii, F. imperialis and F. raddeana. We studied their phylogenetic relationships with AFLP’s, crossing experiments and morphological observations. The AFLP data confirm that F. eduardii is a separate species and not a variety of F. imperialis. Within F. eduardii the two earlier distinguished varieties can indeed be recognised. Our AFLP results also show that F. chitralensis, originally described as F. imperialis var. chitralensis, is different from F. imperialis and is a species in its own right. The results of the AFLP’s and the crossing experiments show that within F. imperialis two varieties can be recognised, one variety containing representatives that possesses the so called ‘foxy’ smell, and a second variety with odourless representatives. A new name for this odourless variety is proposed. © 2014, Springer-Verlag Wien.

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