Fruit Research and Development Station Bistrita

Bistriţa Bârgăului, Romania

Fruit Research and Development Station Bistrita

Bistriţa Bârgăului, Romania
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Scorza R.,U.S. Department of Agriculture | Callahan A.,U.S. Department of Agriculture | Dardick C.,U.S. Department of Agriculture | Cambra M.,Instituto Valenciano Of Investigaciones Agrarias | And 4 more authors.
Acta Horticulturae | Year: 2013

Over the past 20 years an intensive international research project has focused on the development of GE resistance to Plum pox virus (PPV), the causative agent of Sharka, one of the most destructive diseases of plum and other stone fruits. A result of this effort has been the development of 'HoneySweet' plum, a GE cultivar that has proven to be highly resistant to PPV, as demonstrated in over 15 years of study and field testing in the US and Europe. The efficacy and safety of 'HoneySweet' demonstrated in many laboratory, greenhouse and field studies have been validated through the successful regulatory approval of this PPV resistant GE plum cultivar in the US. The international collaborative program that produced 'HoneySweet' demonstrates the potential for publicly-fund research and development to provide safe, efficacious GE products for the benefit of growers and consumers. 'HoneySweet' plum represents a valuable genetic resource for PPV control in the US and in Europe.

Ion L.,University of Bucharest | Zagrai I.,Fruit Research and Development Station Bistrita | Moale C.,Fruit Research and Development Station Constanta | Preda S.,Fruit Research and Development Station Valcea | And 2 more authors.
Scientific Papers of the Research Institute for Fruit Growing | Year: 2011

Plum pox virus (PPV) is a potyvirus that causes Sharka disease in infested stone fruit trees (Prunus species, peach, apricot and plum). It causes severe losses in productivity and fruit quality in European stone fruit orchards. As PPV is transmitted by aphids in a non-persistent manner, the use of pesticides to reduce PPV dissemination is ineffective. (Atanassov D., 1932). Therefore, breeding new plum cultivars resistant or tolerant to Sharka disease is necessary for effective control of PPV in orchards and nurseries. The majority of plum cultivars show different level of susceptibility to PPV. The Romanian cultivar "Andreea" belongs to highly tolerant plum cultivars: only few symptoms are observed on leaves and virus particles are present in plant tissues in low concentration (Zagrai I. et al. 2005). Also the study of local plum genotypes concerning the resistance to PPV, is an important precondition for improvement a new breeding program in plum.

Zagrai I.,Fruit Research and Development Station Bistrita | Ravelonandro M.,French National Institute for Agricultural Research | Gaboreanu I.,University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca | Ferencz B.,The Interdisciplinary Center | And 5 more authors.
Journal of Plant Pathology | Year: 2011

The serological and genetic variability of Plum pox virus (PPV) isolates from transgenic plum trees expressing the PPV coat protein gene and conventional plums was analyzed. PPV isolates were characterized serologically by TAS-ELISA using PPV-D and PPV-M specific monoclonal antibodies and by molecular typing across three genomic regions as well as RFLP analysis of the 3' terminus of the CP gene. PCR products spanning the (Cter)CP and (Cter)NIb-(Nter)CP regions were sequenced. Sequence information revealed no significant difference between serological and molecular features of PPV isolates from transgenic and conventional plums that were growing together in experimental orchards for 6-8 years. These results show that transgenic plums do not promote the emergence of new PPV variants under field conditions.

Scorza R.,Agricultural Research Service Appalachian Fruit Research Station | Callahan A.,Agricultural Research Service Appalachian Fruit Research Station | Dardick C.,Agricultural Research Service Appalachian Fruit Research Station | Ravelonandro M.,French National Institute for Agricultural Research | And 5 more authors.
Plant Cell, Tissue and Organ Culture | Year: 2013

Sharka disease, caused by Plum pox virus (PPV) was first recorded in Bulgaria during the early twentieth century and since that first report, the disease has progressively spread throughout Europe and more recently to Asia, Africa, North and South America. Few PPV resistance genes have been found to naturally occur in Prunus and this has led to the investigation of biotech approaches to the development of resistance through genetic engineering (GE). A notable example of the utility of this approach is 'HoneySweet' plum. PPV protection in this case is based on RNA interference (RNAi) and resistance has been shown to be highly effective, stable, durable, and heritable as a dominant trait. Extensive testing and risk assessment of 'HoneySweet' in laboratory, greenhouse and in the field for over 20 years has demonstrated not only the effectiveness but also the safety of the technology. 'HoneySweet' has been cleared for cultivation in the USA. By the appropriate regulatory agencies. The development and regulatory approval of 'HoneySweet' demonstrate the ability of RNAi technology to contribute to the sustainability of stone fruit production in regions impacted by PPV. Although it has taken almost 100 years since the identification of sharka, we are now able to effectively protect stone fruit species against this disease through the application of GE. © 2013 Springer Science+Business Media Dordrecht (outside the USA).

Zagrai I.,Fruit Research and Development Station Bistrita | Ravelonandro M.,French National Institute for Agricultural Research | Zagrai L.,Fruit Research and Development Station Bistrita | Scorza R.,U.S. Department of Agriculture | Minoiu N.,Fruit Research and Development Station Bistrita
Acta Horticulturae | Year: 2011

Transgenic plums of Prunus domestica L. transformed with the Plum pox virus coat protein gene (PPV-CP) were the subjects of three experiments undertaken in Romania. In the first experiment PPV-CP transgenic clones C2, C3, C4, C5, C6 and PT3 were evaluated for sharka resistance under high natural infection pressure. Transgenic clone C5, subsequently named 'HoneySweet', showed high resistance to PPV. None of the C5 trees became naturally infected by aphids for more than ten years. The resistance of C5 was based on post-transcriptional gene silencing (PTGS). In the second experiment we assessed the effect of two heterologous viruses (Prunus necrotic ringspot virus and Prune dwarf virus) on the efficacy and stability of PTGS-mediated resistance to PPV displayed by the C5 plum. The engineered resistance to PPV in C5 transgenic plums was stable and was not suppressed by the presence of the assayed heterologous viruses. Some PPV-CP transgenic plum clones that are susceptible to PPV including C2, C3, C4 and PT3 display a constitutive transcription of PPV-CP sequence. In the third experiment we used these plants to assess the environmental safety issues related to potential hazards concerning the emergence of PPV variants. The serological and molecular variability of PPV detected in transgenic and in conventional plums revealed that the transgenic plums do not affect the diversity of indigenous PPV populations. We conclude that the safety and efficacy data developed in Romania, and other European countries and in the USA over the last 15 years justify an expansion of the field tests in Romania and in other countries that are experiencing the damages to plum production caused by PPV.

Zagrai I.,Fruit Research and Development Station Bistrita | Zagrai L.,Fruit Research and Development Station Bistrita | Festila A.,Fruit Research and Development Station Bistrita | Baias I.,Fruit Research and Development Station Bistrita | And 3 more authors.
Acta Horticulturae | Year: 2013

A certification program focused on plum was established at Fruit Research & Development Station Bistrita, Romania started with 2008. The objective was to obtain in the first step the prebasic material and, subsequently, to establish plum mother plantations with basic material satisfying the EPPO recommended certification standards. Fifteen plum (Prunus domestica) cultivars ('Iulia', 'Matilda', 'Geta', 'Zamfira', 'Ivan', 'Dani', 'Doina', 'Romaner', 'Elena', 'Jubileu 50', 'Flora', 'Renclod d'Althan', 'Stanley', 'Anna Späth' and 'Carpatin') were subjected to this work. Selected plum trees from experimental orchards were monitored and tested for pathogens listed in EPPO standards. One shoot was then collected from each candidate and tested before grafting onto virus-free 'Myrobolan 29C' rootstock. Selected clones were also tested on woody indicators 'GF 305'. Propagated material was individually tested one year later. The fifteen cultivars were found virus free both before and after propagation. Consequently, the propagated material was certified as 'Prebasic category' and preserved to the nuclear-stock collection. Scions of ten plum cultivars ('Iulia', 'Matilda', 'Geta', 'Zamfira', 'Ivan', 'Romaner', 'Elena', 'Renclod d'Althan', 'Stanley', 'Anna Späth') from prebasic material were used to produce 'Basic category' by grafting onto virus-free 'Myrobolan 29C' rootstock. Propagated plants were individually tested during the vegetative period. All tests (in both steps to obtain prebasic and basic category, respectively) were done according to the EPPO recommendations. DAS-ELISA was used for Plum pox virus (PPV), Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV), Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV) and Myrobalan latent ringspot virus (MLRSV). To increase the sensitivity of PPV and PDV detection, IC-RT-PCR was performed. Nested-PCR method was made to detect 'Candidatus Phytoplasma prunorum' that cause European stone fruit yellows (ESFY). The results obtained allowed to certify 90 plants of the fifteen cultivars (6 plants/cultivar) as 'Prebasic category' in the first step, and 93 plants of the ten cultivars as 'Basic category' in the second step.

Jakab-Ilyefalvi Z.,Fruit Research and Development Station Bistrita | Platon I.,Fruit Research and Development Station Bistrita | Festila A.,Fruit Research and Development Station Bistrita
Scientific Papers of the Research Institute for Fruit Growing | Year: 2012

At Bistrita Fruit Research and Development Station, in a pear collection, planted with 44 varieties, there has been studied the susceptibility to fire blight (Erwinia amylovora,Burill). During the vegetation period, phytosanitary treatments to control the disease have been applied using copper based products (copper sulfate, Champion, Funguran, Kocide). Erwinia amylovora infections have been influenced by the rainfall registered in April (70.9 mm) and May (104.7 mm) and the temperature fluctuations in April-May. The field observations on Erwinia amylvora attack demonstrate that the pear varieties have a different susceptibility to this dangerous bacterium. Evaluation of attack level in the pear collection was done using an evaluation scale with 9 scores using a reference resistance scale for : 'Highly resistant' , 'Moderately resistant', 'Susceptible', 'Very susceptible' cultivars . The most sensitive pear varieties in the collection were: 'De Noiembrie', 'Abatele Fetel', 'Daciana', 'Triumf', 'Williams Boway', 'Margareta Marillat', 'Beauty Tomme', 'Williams rosu', 'Aromata de Bistrita', 'Jeanne d'Arc', 'Aramiu de Somes', 'Belle des Arbres', 'Zorka' representing 13.64% of the total pear varieties. In several cultivars there have been observed increased symptoms, a very high susceptibility of infections leading to complete scorching of trees: Jeanne d'Arc', Williams rosu', 'Triumf', 'Aromata de Bistrita', 'Zorka'. Strong attack symtoms were observed at the pear cultivars 'Cure', 'Euras, 'Ciuda' 'Highland', 'Precoce Morettini', 'Monica', 'Cadillac', 'Juliana', 'Somesan', 'Beurré Hardenpont' these cultivars being susceptible to Erwinia amylovora , representing 40.91 % of total genotypes . Cultivars 'Untoasa Geoagiu', 'Beurre Hardy', 'Trivale' manifested a certain tolerance to Erwinia amylovora , no attack symptoms being observable at these varieties, in 6,82 % of total studied cultivars scores ranged between 8.0-8.22. Notably amount of genotypes were included in the "Moderately resistant" category (34.04 %) 'Untoasa de Transilvania', 'Starkrimson', 'Josephine des Malignes', 'Untoasa Bosc', 'Magnes', 'Contesa de Paris', 'Doina', 'Napoca', 'Carpica', 'Karamanka', 'Williams', 'Expozitie', ' Ina Estival', 'Passe Crassagne', 'Conference'.

Jakab-Ilyefalvi Z.,Fruit Research and Development Station Bistrita
Annals of the Romanian Society for Cell Biology | Year: 2016

The aim of the study was to investigate the three dimensional (3D) structure through scanning electron microscopy of the hypha haustoria of apple powdery mildew (Podosphaera leucotricha, Ell and Ev.) fungi, the mode of infection and entering the apple leaf mesophyll in late autumn at the susceptible cultivar ‘Jonathan’. Results showed that the haustoria enters the leaf perpendicularly like a drill causing a whole in the leaf mesophyll, the conection part of the haustoria is thickened having a diameter at the base of 10-15 μm. The haustoria are convoluted and folded in multiple ways having a vavy surface, they entered directly through the epidermis, the stomata were not affected. In late autumn the infected leaves were attacked massively. A group of sexual spores with ascospores were identified as a larger group of tight sacks with an average diameter of 2-3 μm being connected at the bottom of the haustoria. Several new conidiophores were identified also in the SEM images at secondary infections. © Annals of R. S. C. B.

Vidal E.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Zagrai L.,Fruit Research and Development Station Bistrita | Milusheva S.,Bulgarian Fruit Growing Institute | Bozhkova V.,Bulgarian Fruit Growing Institute | And 4 more authors.
Annals of Applied Biology | Year: 2013

The application of horticultural mineral oil (HMO) treatments has been reported as a possible control strategy to reduce Plum pox virus (PPV) incidence in Prunus nurseries. The effect of Sunspray Ultrafine HMO at 1% on the natural viral spread was evaluated in experimental nursery plots of Nemaguard and Mariana GF8-1 Prunus rootstock blocks established under high natural inoculum pressure of the most prevalent PPV-types. Tests were conducted in experimental nursery plots in Plovdiv, Bulgaria (PPV-M and PPV-Rec), in Bistrita, Romania (PPV-D and PPV-Rec) and in Llíria, Spain (PPV-D). Horticultural mineral oil treatments were applied weekly during the vegetative period from spring to fall (treatments were interrupted in the summer). Nursery plants were analysed yearly by double-antibody sandwich enzyme-linked immunosorbent assay with 5B-IVIA/AMR monoclonal antibodies. The population dynamics of the aphids visiting plants in each experimental nursery plot was monitored by the sticky-shoot method and also by Moericke yellow water traps. At all three locations, the aphid population first peaked in the springtime. Furthermore, a variable second peak of aphid population was observed in Plovdiv and Bistrita in autumn. The treatments reduced PPV incidence in the three experimental locations and plots and in both assayed Prunus rootstocks grown under high PPV-inoculum pressure. A reduction from 10% to 20% of PPV-incidence between treated and control plants (P < 0.05) in Plovdiv and Bistrita, respectively, was observed at the end of the tests. However, HMO treatments did not prevent PPV infection altogether, probably because of the high PPV prevalence in the area near the experimental nursery blocks. The control of PPV in nursery blocks based on HMO is presented as an environmentally friendly strategy based on the physical action of the treatments. © 2013 Association of Applied Biologists.

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