Publications by authors named "N Vassilakos"

33 Publications

Association of citrus virus A to citrus impietratura disease symptoms.

Phytopathology 2021 Mar 11. Epub 2021 Mar 11.

Benaki Phytopathological Institute, 69064, 8, St. Delta str.,, Kifissia, Athens, Greece, 145 61;

Citrus impietratura disease (CID) is a graft transmissible, virus-like disease observed in old-line citrus trees; its characteristic symptom is the appearance of gum in the albedo of the affected fruits. To identify the causal agent of the disease, high throughput sequencing (HTS) was performed on symptomatic orange fruits. The analysis of the obtained data revealed in all samples, mixed infections of viroids commonly found in citrus trees together with the recently described citrus virus A (CiVA). Examination of additional symptomatic fruits with conventional RT-PCRs led to the identification of a single CiVA infection in one tree, which was verified by HTS. Indexing of the single CiVA-infected tree on indicator plants resulted in the appearance of characteristic symptoms in the leaves that were correlated with virus accumulation. Moreover, a comparative analysis among symptomatic and asymptomatic fruits derived from the same trees was performed and included the single CiVA-infected orange tree. The analysis revealed a positive correlation between the appearance of symptoms and the accumulation of CiVA RNAs. To facilitate CiVA detection during certification programs of propagation material a quantitative RT-qPCR targeting the movement protein of the virus, was developed and evaluated for reliable and sensitive detection of the virus. To the best of our knowledge this is the first study that associates CiVA with the appearance of impietratura disease symptoms.
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http://dx.doi.org/10.1094/PHYTO-01-21-0027-RDOI Listing
March 2021

The plasma membrane Cation binding protein 1 affects accumulation of Potato virus Y in pepper both at the systemic level and in protoplasts.

Virus Res 2020 04 14;280:197899. Epub 2020 Feb 14.

Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Virology, 14561 Kifissia, Greece. Electronic address:

The Plasma membrane Cation binding Protein 1 (PCaP1) has been shown to be important for the intra-cellular movement of two members of the Potyvirus genus in arabidopsis and tobacco plants. In this study, the orthologous PCaP1 gene of pepper (Capsicum annuum) was examined for its role in the accumulation of Potato virus Y, type member of the Potyvirus. Downregulation of C. annuum PCaP (CaPCaP) through tobacco rattle virus-induced gene silencing, resulted in lower accumulation of potato virus Y (PVY) in pepper plants. Using an improved pepper protoplast isolation protocol, we showed that knockdown of CaPCaP negatively affected PVY accumulation at the within-cell level in pepper in contrast with the turnip mosaic virus-arabidopsis pathosystem. Conversely, following overexpression of CaPCaP, the accumulation of PVY at the systemic level was increased. The results provide further knowledge on the role of PCaP in the potyvirus infection process and reveal differences of its action among different pathosystems.
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http://dx.doi.org/10.1016/j.virusres.2020.197899DOI Listing
April 2020

Bacillus amyloliquefaciens MBI600 differentially induces tomato defense signaling pathways depending on plant part and dose of application.

Sci Rep 2019 12 13;9(1):19120. Epub 2019 Dec 13.

Institute of Molecular Biology and Biotechnology, FORTH, 100N. Plastira str, 70013, Heraklion, Greece.

The success of Bacillus amyloliquefaciens as a biological control agent relies on its ability to outgrow plant pathogens. It is also thought to interact with its plant host by inducing systemic resistance. In this study, the ability of B. amyloliquefaciens MBI600 to elicit defense (or other) responses in tomato seedlings and plants was assessed upon the expression of marker genes and transcriptomic analysis. Spray application of Serifel, a commercial formulation of MBI600, induced responses in a dose-dependent manner. Low dosage primed plant defense by activation of SA-responsive genes. Suggested dosage induced defense by mediating synergistic cross-talk between JA/ET and SA-signaling. Saturation of tomato roots or leaves with MBI600 elicitors activated JA/ET signaling at the expense of SA-mediated responses. The complex signaling network that is implicated in MBI600-tomato seedling interactions was mapped. MBI600 and flg22 (a bacterial flagellin peptide) elicitors induced, in a similar manner, biotic and abiotic stress responses by the coordinated activation of genes involved in JA/ET biosynthesis as well as hormone and redox signaling. This is the first study to suggest the activation of plant defense following the application of a commercial microbial formulation under conditions of greenhouse crop production.
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http://dx.doi.org/10.1038/s41598-019-55645-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6910970PMC
December 2019

One-Step Multiplex Quantitative RT-PCR for the Simultaneous Detection of Viroids and Phytoplasmas.

Methods Mol Biol 2019 ;1875:151-157

Department of Phytopathology, Laboratory of Virology, Benaki Phytopathological Institute, Athens, Greece.

A one-step multiplex quantitative reverse transcription polymerase chain reaction protocol is described, for the detection in pome trees of Pear blister canker viroid and Apple scar skin viroid, together with universal detection of phytoplasmas. Total nucleic acids extraction is performed according to a modified CTAB protocol and TaqMan MGB probes are used to surpass high genetic variability of viroids. The multiplex real-time assay is at least ten times more sensitive than conventional protocols and its features make it suitable for rapid and massive screening of pome fruit trees phytoplasmas and viroids in certification schemes and surveys.
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http://dx.doi.org/10.1007/978-1-4939-8837-2_12DOI Listing
June 2019

Bacillus amyloliquefaciens strain MBI600 induces salicylic acid dependent resistance in tomato plants against Tomato spotted wilt virus and Potato virus Y.

Sci Rep 2018 07 9;8(1):10320. Epub 2018 Jul 9.

Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion/Crete, GR-71110, Greece.

Plant growth promoting rhizobacteria have been proposed as effective biocontrol agents against several fungal and bacterial plant pathogens. However, there is limited knowledge regarding their effect against viruses. In this study, Bacillus amyloliquefaciens strain MBI600 (MBI600), active ingredient of the biological fungicide Serifel® (BASF SE), was tested for its antiviral action in tomato plants. Drench, foliar or soil amendment applications of MBI600 reduced up to 80% the incidence of Tomato spotted wilt virus under two different sets of environmental conditions. In addition, drench application of MBI600 delayed Potato virus Y systemic accumulation. Transcriptional analysis of a range of genes associated with salicylic acid (SA)- or jasmonic acid - related defense, priming or basal defense against viruses, revealed the induction of the SA signaling pathway in tomato after MBI600 treatment, and discrete gene expression patterns in plant response to TSWV and PVY infection.
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http://dx.doi.org/10.1038/s41598-018-28677-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6037670PMC
July 2018