Virology & Mycology
Open Access
ISSN: 2161-0517
+44 1223 790975
ISSN: 2161-0517
+44 1223 790975
Diana Leibman, Dalia Woolf and Amit Gal-On
Agricultural Research Organization, Israel
Scientific Tracks Abstracts: Virol Mycol
RNA-dependent RNA polymerases (RDR) play an important role in virus protection and plant gene control. Their activity is based on the synthesis of double stranded RNA that is a template for the gene silencing system. Four RDR1 (RDR1a, b, c1, c2) genes were identified in cucumber having different expression levels before and after infection by various viruses. The CsRDR1a, b, c genes have a homology of 60-58% at the amino acid level, while CsRDR1c1 and c2 are almost identical (97% homology), but have different promoter sequences. A high expression level of CsRDR1b was characterized in cucumber strains with partial resistance to a number of viruses, while CsRDR1c1 and c2 not expressed in healthy plants. Cucumber plants infected by several different viruses showed a moderate expression level of CsRDR1b and a dramatic level of CsRDR1c1, c2. The expression level of CsRDR1a, CsRDR2 and CsRDR6 did not increase following virus infection. The differential expression of CsRDR1b and CsRDR1c1, c2 indicates dissimilar control of these genes. The relationship between the high levels of expression of CsRDR1b in resistant cucumber cultivars reinforces the assumption that this gene is unique for virus resistance. Using the CRISPR/Cas9 system, we created a variety of mutants in the rdr1b and rdr1c1 and c2 genes. Knockdown of these genes increased virus accumulation. Plants with a homozygous mutation in the rdr1b genes (deletion of 34 nucleotides) and rdr1c (2 and 1 nucleotides in the rdr1c1 and rdr1c2 genes respectively) showed increased susceptibility to Cucumber mosaic virus 4 dpi, especially rdr1c mutants plants which collapse 6 days after infection. The viral symptoms increased also after Cucurbit vein yellowing virus infection, whereas the susceptibility to Zucchini yellow mosaic virus infection was less. Notably, CsRDR1b expression in healthy rdr1b mutants was less than in non-mutant plants. The control of CsRDR1b and CsRDR1c1, c2 is under study in our laboratory to help understand the silencing mechanism of plants defense.
Recent Publications
1. Leibman D, Kravchik M, Wolf D, Haviv S, Weissberg M, Ophir R, Paris H S, Palukaitis P, Ding S W, Gaba V and GalOn A (2017) Differential expression of cucumber RNA-dependent RNA polymerase 1 genes during antiviral defense and resistance. Molecular Plant Pathology 19(2):300-312.
2. Chandrasekaran J, Brumin M, Wolf D, Leibman D, Klap C, Pearlsman M, Sherman A, Arazi T and Gal-On A (2016) Development of broad virus resistance in non-transgenic cucumber using CRISPR/Cas9 technology. Molecular Plant Pathology 17(7):1140-53.
3. Leibman D, Wolf D, Saharan V, Zelcer A, Arazi T, Shiboleth M Y, Gaba V, and Gal-On A (2011) A high level of transgenic viral small RNA is associated with broad potyvirus resistance in cucurbits. Molecular Plant-Microbe Interactions 24(10):1220��? 1238.
Diana Leibman completed her PhD in 2012 from the Hebrew University in Jerusalem. She works as a Research Engineer in the Agricultural Research Organization, The Volcani Center. The research topics in which she is involved are: The role of RNA-dependent RNA polymerase 1 in plant defense against viruses; CRISPR/Cas9 genome editing technology for crop improvement; development of resistance to RNA and DNA viruses in cucurbits and tomato by transgenic approaches; identification of plant genes associated with disease symptom development to plant virus infection and; genetic engineering of attenuated ZYMV-AG as a plant virus vector, for gene expression and epitope presentation.
E-mail: diana@agri.gov.il