Typing and distribution of Plum pox virus isolates in Romania

Plum pox or Sharka, caused by Plum pox virus (PPV) is considered the most destructive disease of plum. Although PPV is widespread in all plum growing areas of Romania and causes serious yield losses, little is known about the variability of its isolates at a country level. For this reason, a large-scale study was performed with the aim of obtaining a picture of the prevalence and distribution of PPV strains in plum. During a three year survey, 200 PPV isolates collected from 23 different plum orchards from Transylvania, Moldavia and Muntenia areas were investigated. DASELISA and IC-RT-PCR were used for PPV detection. PPV strains were serologically determined by TAS-ELISA using PPV-D and PPV-M specific monoclonal antibodies. Molecular strain typing was done by IC/RT-PCR targeting three genomic regions corresponding to (Cter)CP, (Cter)NIb/(Nter)CP and CI. RFLP analysis was used to distinguish D and M strains, based on the RsaI polymorphism located in (Cter)CP. To confirm the presence of PPV-Rec strain, 13 PCR products spanning the (Cter)NIb/(Nter)CP were sequenced. Overall results showed that in Romania the predominant strain is PPV-D (73%), followed, with a much lower frequency, by PPV-Rec (14%). Mixed infections (PPV-D+PPVRec), which might generate additional variation by recombination, are also frequent (13%).Keywords: Romania, PPV strains, DAS/TAS-ELISA, IC/RT-PCR, RFLP, sequencin

Typing and distribution of Plum pox virus isolates in Romania. Julius-Kuhn-Archiv

Abstract Plum pox or Sharka, caused by Plum pox virus (PPV) is considered the most destructive disease of plum. Although PPV is widespread in all plum growing areas of Romania and causes serious yield losses, little is known about the variability of its isolates at a country level. For this reason, a large-scale study was performed with the aim of obtaining a picture of the prevalence and distribution of PPV strains in plum. During a three year survey, 200 PPV isolates collected from 23 different plum orchards from Transylvania, Moldavia and Muntenia areas were investigated. DAS-ELISA and IC-RT-PCR were used for PPV detection. PPV strains were serologically determined by TAS-ELISA using PPV-D and PPV-M specific monoclonal antibodies. Molecular strain typing was done by IC/RT-PCR targeting three genomic regions corresponding to (Cter)CP, (Cter)NIb/(Nter)CP and CI. RFLP analysis was used to distinguish D and M strains, based on the RsaI polymorphism located in (Cter)CP. To confirm the presence of PPV-Rec strain, 13 PCR products spanning the (Cter)NIb/(Nter)CP were sequenced. Overall results showed that in Romania the predominant strain is PPV-D (73%), followed, with a much lower frequency, by PPV-Rec (14%). Mixed infections (PPV-D+PPV-Rec), which might generate additional variation by recombination, are also frequent (13%)

Transgenic plums expressing plum pox virus coat protein gene do not assist the development of virus recombinants under field conditions

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

Statistical model for Plum pox virus prediction in Prunus nursery blocks using vector and virus incidence data in four different European ecological areas

This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Plum pox virus(PPV) is the causal agent of sharka, the most devastating virus disease ofPrunusspecies. PPV is transmitted by vegetative propagation, particularly by grafting, as well as by aphid species in a nonpersistent manner. The objective of this paper was to evaluate the prevalence and diversity of PPV-vector aphid species in representative European areas of prunus cultivation. Four experimental nursery plots were established in Skierniewice (Poland), Liria (Spain), Plovdiv (Bulgaria) and Bistrita (Romania). Aphid population was weekly monitored using the sticky shoot method in spring and/or autumn in each nursery plot. Furthermore, we estimated the relative efficiency factor for the main PPV-vector aphid species using bibliographic and reference data. Aphid diversity in each nursery plot was assessed using the Shannon index and the number of estimated aphid species was calculated by the rarefaction method. The highest diversity of aphid species population was reported in Plovdiv in spring while the lowest diversity was found in Liria in spring. A cluster analysis based on Morisita-Horn similarity index was performed to study the differences in species composition between the four nursery plots and seasons. Aphid population was clearly grouped by location and season. Results showedAphis spiraecolaandHyalopterus prunicomplex were typically spring aphid species, whileAnoecia corniandRhopalosiphum padidominated autumn catch. Regarding PPV-vector aphid species present in nursery plots,A. spiraecolawas the most prevalent PPV-vector aphid species in Liria and in Bistrita, showing a high relative efficiency factor of PPV transmission (0.91). Consequently,A. spiraecolashould be considered a key actor in the spread of PPV in these regions.Hyalopterus prunicomplex was the most prevalent PPV-vector aphid species in Skierniewice and Plovdiv, showing a very low relative efficiency factor of PPV transmission (0.09). Therefore, the role ofH. prunicomplex in spread of PPV in these regions can be considered negligible. Furthermore, we statistically demonstrated that the presence of specific PPV-vector aphid species is associated with the spread of the disease, whereas the biodiversity of aphid species population does not affect the spread of PPV. Finally, the advantages of the use of vector pressure index in the management of sharka disease are discussed.The research leading to these results were funded by the EU Seventh Framework Programme (FP7/2007-2013), SharCo project grant no. 204429 and by grants from the Spanish Ministry of Science and Education (MEC, AGL2009-07531 and INIA RTA2005-00190). Authors thank I. Baias, S. Sabin (SCDP, Bistrita), B. Tamargo and J. Micó (Cooperativa Vinícola, Líria) for technical assistance in the experimental plots, Viveros Orero and Agromillora Iberia for providing the certified rootstock plants. E. Vidal was recipient of a grant from the Spanish Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA).Vidal, E.; Zagrai, LA.; Malinowski, T.; Soika, G.; Warabieda, W.; Tasheva-Terzieva, E.; Milusheva, S.... (2020). Statistical model for Plum pox virus prediction in Prunus nursery blocks using vector and virus incidence data in four different European ecological areas. 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