Special Issue "Plant Viruses"

Guest Editor
Prof. Dr. Henryk Czosnek
Institute of Plant Sciences and Genetics in Agriculture; Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
Website: http://departments.agri.huji.ac.il/plantscience/staff-eng/czosnek.html
E-Mail:
Phone: + 972 8 9489249
Fax: + 972 8 9468265
Interests: genetic engineering; molecular genetics; plant genetic engineering; biotechnology in agriculture; aspects of plant molecular biology

Submission

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• classification of plant viruses
• diseases, symptoms, and damages to plants
• morphology of virions and structure of genome
• detection methods
• origin, evolution and phylogeny
• transmission and vectors
• replication and expression
• plant-virus interactions, plant defense, resistance genes
• silencing of viruses

Type of Paper: Article
Title: A Simplified Method for the Simultaneous Detection of  Southern Rice Black Streaked Dwarf Virus and Rice Ragged Stunt Virus with RT-PCR
Authors: Liang Bi, Zhuo Chen, Zhenchao Wang, Mengjiao Zeng, Dandan Yu, Xiangyang Li, Jiaju Liu, Linhong Jin, Deyu Hu, Song Yang *, and Baoan Song *
Affiliations: State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering/ Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, P. R. China; E-Mails:  gs.lbi09@mail.gzu.edu.cn(L.B.) (L.B.); fcc.zchen@gzu.edu.cn (C.Z.); gs.zcwang@mail.gzu.edu.cn (Z.C.W.);  dandanyu0813@hotmail.com (D.D.Y.); gs.lixy09@mail.gzu.edu.cn (X.Y.L.); JJL: liujiaju1987@126.com(J.J.L.); fcc.jinlh@gzu. edu.cn(L.H.J.);fcc.dyhu@gzu.edu.cn(D.Y.H.); School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China; E-Mail: gzgyzmj@hotmail.com
* Author to whom correspondence should be addressed; E-Mail: basong@gzu.edu.cn; fcc.syang@gzu.edu.cn; Tel.: +08513620521; +08518292171; Fax: +08513622211 (B.A.S.)
Abstract: In recent years, rice fields southwest of China have been widely infected by southern rice black-streaked dwarf virus (SRBSDV) and rice ragged stunt virus (RRSV). Identification of the pathogens involved in such infections is usually the first step toward determining better protective measures for rice. In the present work, we designed two pairs of special primers and optimized experimental conditions and systems to establish a rapid and accurate method for the simultaneous detection of SRBSDV and RRSV. Compared with simplex RT-PCR, an increase in sensitivity for SRBSDV detection and no decrease in sensitivity for RRSV detection were observed in duplex RT-PCR. The latter procedure can strongly identify the viruses and provides technical support for the detection and analysis of rice viruses.
Keywords: RRSV; SRBSDV; RT-PCR; detection; RT-PCR

Type of Paper: Review
Title: Biological Invasion of Phytoviruses Transmitted by Arthropod Vectors: The Case Study of TYLCV and Bemisia Tabaci in Réunion Island
Authors: Frédéric Péréfarres, Magali Thierry, Pierre Lefeuvre, Nathalie Becker, Bernard Reynaud, Hélène Delatte, Jean-Michel Lett
Affiliation: UMR "Peuplements Végétaux et Bioagresseurs en Milieu Tropical", (PVBMT), CIRAD - Pôle de Protection des Plantes, Laboratoire de Pathologie et de Génétique Moléculaire, Ligne Paradis, 97410 Saint-Pierre, Ile de La Réunion, Tél: 02.62.49.92.34, Fax: 02.62.49.92.93, E-mail : lett@cirad.fr
Abstract: Biological invasions on islands provide ideal fields to study ecological and evolutionary processes between invasive and native populations. Invasions of arthropod vectors and viruses are the main factors associated with viral emerging diseases. Before the introduction of the world invasive biotype B of Bemisia tabaci in the late 1990s, Reunion Island (South West Indian Ocean) exclusively hosted an indigenous biotype of B. tabaci, the Ms. Similarly, while no begomoviruses had been reported on this island, the two main strains of one of the most damaging and emerging plant virus in the world, the Mild and Israel strains of the Tomato yellow leaf curl virus (TYLCV-Mld and TYLCV-IL), were successively introduced in 1997 and 2004 respectively. These introductions deeply modified the agricultural landscape in Reunion Island and allowed us to better understand ecological and genetic mechanisms involved in biological invasions and competitions.

Type of Paper: Review
Title: Tobacco Rattle virus -based Post Transcriptional Gene Silencing (TRV-PTGS) to discover host genes involved in the infection by the Tomato yellow leaf curl virus family and in the establishment of resistance to the virus
Authors: Czosnek , H. ¹, Eybishtz, A. ¹,  Sade, D. ¹,  Bejarano, E. ²,  Rosas-Díaz, T. ², and Lozano-Duran, R. ²
Affiliations: ¹ Institute of Plant Science and genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
² Departamento de Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterranea (UMA), Universidad de Málaga, Campus de Teatinos. 29071 Málaga, Spain.
Abstract: We have proposed to use a TRV-VIGS RNAi-based screen to uncover the genes and gene networks underlying Tomato yellow leaf curl virus (TYLCV) resistance in tomato and identify host factor involved in the viral infection. As a first approach genes preferentially expressed in resistant plants (compared to susceptible), and up-regulated upon TYLCV infection were selected to determine if silencing the genes will lead to the collapse of resistance or induce resistance in sensitive lines. To decipher the networks of resistance we have used two inbred tomato lines: one was resistant (R), the other was susceptible (S) to the virus. Sixty nine genes preferentially expressed in R tomatoes were identified by differential screening of cDNA libraries from infected and uninfected R and S tomato plants. From the twenty genes silenced so far, eight answered to this criterion: their silencing led to the total collapse of resistance. The hierarchy of the resistance signalling pathway is being deciphered by silencing one gene at a time and measuring the transcriptional activity of the others. In addition a home-designed oligonucleotide microarray representing all the genes discovered so far in tomato has been used to analyze gene cross-talk upon infection of R and S lines and upon silencing of a single gene. In a second approach we explore the potential of 2IRGFP Nicotiana benthamiana plants in combination with VIGS to identify host genes with a role in geminivirus infection. We have achieved an accurate description of the dynamics of viral replication by monitoring GFP expression in both space and time, explored the limitations of the strategy to be used in a reverse-genetics screening, and unveiled the effect of silencing selected N. benthamiana genes. Using this strategy, we have identified eighteen genes involved in several cellular processes whose silencing alters geminivirus infection: with a potential anti-viral effect, are required for a full infection. Hence, our results provide new insights into the molecular mechanisms underlying geminivirus resistance and infections, and at the same time reveal the VIGS system as a powerful tool for functional reverse genetics studies.

Type of Paper: Article
Title: Diversity of Dicotyledenous-infecting Geminiviruses and their Associated DNA Molecules in Southern and Eastern Africa
Authors: M. E. C. Rey, J. Ndunguru, O. A. Ndomba, L.C. Berrie, M. Paximadis, S. Berry, N. Cossa, V. N.Nuaila, K.G. Mabasa and L.L. Esterhuizen
Affiliations: School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, P O Wits 2050, Johannesburg, South Africa; E-Mail: chrissie.rey@wits.ac.za
Abstract: Geminiviruses (circular ssDNA), belonging to the family Geminiviridae, are plant-infecting viruses causing severe economic losses to agricultural production worldwide, including sub-Saharan Africa. The largest, most diverse and economically important group in the Geminiviridae family includes the genus Begomovirus, whose genomes are either monopartite (one ssDNA component – DNA A) or bipartite (two circular ssDNA - DNA-A and DNA-B).  Some of the Old World monopartite begomoviruses are associated with additional subviral ssDNA components (satellites), termed alpha- or betasatellites (DNA-βs).  Additionally, subgenomic molecules, namely defective interfering (DIs) DNA molecules (usually derived from the parent helper virus and formed as a result of deletions of the viral genome), are also associated with bipartite geminiviruses.  They are usually, but not always, derived from the DNA-B component and are approximately half the size of the DNA-B component.Begomoviruses exhibit considerable diversity in terms of their genome structure, sequence, host range and insect vectors. The past two decades has witnessed the emergence and diversification of new begomoviruses, and associated satellites and DIs, in several African countries, including South Africa, Mozambique, Zimbabwe, Tanzania, Kenya and Malawi and Zambia, on several dicotyledenous crops such as cassava, tobacco, tomatoes, sweet potatoes, beans, and weeds.  This article aims to review, and provide new information, with regard to this important group of viral pathogens that cause huge economic losses in so many edible and subsistence crops in southern and eastern African countries.

Type of Paper: Article
Title: Biological and Molecular Characterization of the Polish Zucchini Yellow Mosaic Virus Isolates
Authors: Beata Hasiów-Jaroszewska^*, Natalia Rymelska, Natasza Borodynko and Henryk Pospieszny
Affiliation: Department of Virology and Bacteriology, Institute of Plant Protection, National Research Institute, u. Wegorka 20, PL-60-318, Poland
* Corresponding author, E-mail: beatahasiow@tlen.pl
Abstract: The diversity of Zucchini yellow mosaic virus (ZYMV) was analyzed by the biological and genetic characterization of isolates collected from cucumber and zucchini plants in various regions of Poland. The isolates differed in their host range and symptoms induced by them on a series of plant species. In addition, the analysis of the genetic diversity of the coat protein (CP) revealed high level of nucleotide variability among the isolates. Comparison of the coat protein sequences of 70 isolates from different geographical regions worldwide revealed that the Polish isolates belong to different groups and they do not form a monophyletic cluster with European isolates. Interestingly, among the central European ZYMV isolates lower variability has been observed previously. The analysis of selection pressure using CP revealed two codons under positive selection. The recombination events between isolates analyzed were also identified. Our results indicate that specific isolates can spread rapidly to geographically adjacent areas but may not be directly related to isolates found in other neighboring countries.