Analysis of the RNA-Dependent RNA Polymerase 1 (RDR1) Gene Family in Melon.

RNA-dependent RNA polymerase 1 (RDR1) plays a crucial defense role against plant viruses by secondary amplification of viral double-stranded RNA in the gene-silencing pathway. In this study, it was found that melon encodes four RDR1 genes ( and similar to the gene family of cucumber (. ).

Characterization of potato virus Y populations in potato in Israel.

Potato virus Y (PVY) is the most common virus infecting potato worldwide. We analysed potato tuber PVY infections from the major Israeli growing region in 2014-2017. Isolates were characterized by multiplex PCR according to Chikh-Ali et al.

prediction and segregation analysis of putative virus defense genes based on SSR markers in sweet potato F1 progenies of cultivars 'New Kawogo' and 'Resisto'.

In sweet potato, an anti-virus defense mechanism termed reversion has been postulated to lead to virus freedom from once infected plants. The objectives of this study were to identify anti-virus defense genes and evaluate their segregation in progenies. Reference genes from different plant species were used to assemble transcript sequences of each sweet potato defense gene .

Factors influencing reversion from virus infection in sweetpotato.

Viruses limit sweetpotato () production worldwide. Many sweetpotato landraces in East Africa are, however, largely virus-free. Moreover, some plants infected by the prevalent Sweet (SPFMV) may be able to revert to virus-free status.

Digital Photography as a Tool of Research and Documentation in Plant Tissue Culture.

Scientific photography is an important and indispensable tool in plant tissue culture research: photographs should be taken throughout a project for documentation. The aim of photography in plant tissue culture should be to illustrate clearly the differentiation, growth, and developmental stages occurring in vitro. Poor-quality scientific photography in tissue culture research and professional reports results in poor documentation.

Differential expression of cucumber RNA-dependent RNA polymerase 1 genes during antiviral defence and resistance.

RNA-dependent RNA polymerase 1 (RDR1) plays a crucial role in plant defence against viruses. In this study, it was observed that cucumber, Cucumis sativus, uniquely encodes a small gene family of four RDR1 genes. The cucumber RDR1 genes (CsRDR1a, CsRDR1b and duplicated CsRDR1c1/c2) shared 55%-60% homology in their encoded amino acid sequences.

Stronger sink demand for metabolites supports dominance of the apical bud in etiolated growth.

The potato tuber is a swollen underground stem that can sprout under dark conditions. Sprouting initiates in the tuber apical bud (AP), while lateral buds (LTs) are repressed by apical dominance (AD). Under conditions of lost AD, removal of tuber LTs showed that they partially inhibit AP growth only at the AD stage.

Immunity to tomato yellow leaf curl virus in transgenic tomato is associated with accumulation of transgene small RNA.

Gene silencing is a natural defense response of plants against invading RNA and DNA viruses. The RNA post-transcriptional silencing system has been commonly utilized to generate transgenic crop plants that are "immune" to plant virus infection. Here, we applied this approach against the devastating DNA virus tomato yellow leaf curl virus (TYLCV) in its host tomato (Solanum lycopersicum L.

HandGun-mediated inoculation of plants with viral pathogens for mechanistic studies.

Particle bombardment is an efficient method for virus inoculation of intact plants. This technique enables inoculation with full-length infectious clone cDNA, PCR products, virus from sap or virus preparation, and in vitro viral transcripts. The inoculation of some phloem-limited RNA and circular DNA viruses is also possible.

Biolistic DNA delivery to leaf tissue of plants with the non-vacuum gene gun (HandyGun).

Non-vacuum gene guns such as HandyGun are flexible tools for bombardment of targets of varying size. Construction of HandyGun is simpler and cheaper than vacuum gene guns and will be described here. The conditions for maximal transient transformation efficiency of plant cells with plasmid DNA using HandyGun will be provided.

Polar auxin transport is essential for gall formation by Pantoea agglomerans on Gypsophila.

The virulence of the bacterium Pantoea agglomerans pv. gypsophilae (Pag) on Gypsophila paniculata depends on a type III secretion system (T3SS) and its effectors. The hypothesis that plant-derived indole-3-acetic acid (IAA) plays a major role in gall formation was examined by disrupting basipetal polar auxin transport with the specific inhibitors 2,3,5-triiodobenzoic acid (TIBA) and N-1-naphthylphthalamic acid (NPA).

Viruses of potato.

Potatoes are an important crop in Mediterranean countries both for local consumption and for export to other countries, mainly during the winter. Many Mediterranean countries import certified seed potato in addition to their own seed production. The local seeds are mainly used for planting in the autumn and winter, while the imported seed are used for early and late spring plantings.

A high level of transgenic viral small RNA is associated with broad potyvirus resistance in cucurbits.

Gene-silencing has been used to develop resistance against many plant viruses but little is known about the transgenic small-interfering RNA (t-siRNA) that confers this resistance. Transgenic cucumber and melon lines harboring a hairpin construct of the Zucchini yellow mosaic potyvirus (ZYMV) HC-Pro gene accumulated different levels of t-siRNA (6 to 44% of total siRNA) and exhibited resistance to systemic ZYMV infection. Resistance to Watermelon mosaic potyvirus and Papaya ring spot potyvirus-W was also observed in a cucumber line that accumulated high levels of t-siRNA (44% of total siRNA) and displayed significantly increased levels of RNA-dependent RNA (RDR)1 and Argonaute 1, as compared with the other transgenic and nontransformed plants.

Effect of a single amino acid substitution in the NLS domain of Tomato yellow leaf curl virus-Israel (TYLCV-IL) capsid protein (CP) on its activity and on the virus life cycle.

The capsid protein (CP) of Tomato yellow leaf curl virus-Israel (TYLCV-IL), encoded by the v1 gene, is the only known component of the viral capsid. Three point mutations introduced into the conserved NLS region of the CP were investigated. One mutant, in which the Arg at position 19 was converted to Leu, had the most significant effect on the CP-CP homotypic interaction as well as on CP's interaction with its nuclear receptor karyopherin α1 and with the protein GroEL.

Characterization of nuclear localization signals in the type III effectors HsvG and HsvB of the gall-forming bacterium Pantoea agglomerans.

HsvG and HsvB, two paralogous type III effectors of the gall-forming bacteria Pantoea agglomerans pv. gypsophilae and P. agglomerans pv.

Inoculation of plants with begomoviruses by particle bombardment without cloning: Using rolling circle amplification of total DNA from infected plants and whiteflies.

A new system for inoculation of plants with begomoviral DNA without cloning or the use insect vectors is described. Total DNA extracted from begomovirus-infected plants was amplified by rolling circle amplification (RCA) using the bacteriophage phi29 DNA polymerase, and inoculated to plants by particle bombardment. Infection rates of up to 100% were obtained using this technique.

HandyGun: An improved custom-designed, non-vacuum gene gun suitable for virus inoculation.

Particle bombardment with a non-vacuum gene gun is an efficient method for transfection of plant cells with cloned viruses and initiation of virus infection. The HandyGun developed in this study is an improved version of a non-vacuum gene gun. Bombardment parameters were studied by inoculating an infectious, 35S promoter-driven cDNA of Potato virus A (PVA; Potyvirus) to the potato clone 'A6', Nicotiana benthamiana and N.

Characterization of Synergy Between Cucumber mosaic virus and Potyviruses in Cucurbit Hosts.

ABSTRACT Mixed infections of cucurbits by Cucumber mosaic virus (CMV) and potyviruses exhibit a synergistic interaction. Zucchini squash and melon plants coinfected by the potyvirus Zucchini yellow mosaic virus (ZYMV) and either Fny-CMV (subgroup IA) or LS-CMV (subgroup II) displayed strong synergistic pathological responses, eventually progressing to vascular wilt and plant death. Accumulation of Fny- or LS-CMV RNAs in a mixed infection with ZYMV in zucchini squash was slightly higher than infection with CMV strains alone.

Inoculation of plants using bombardment.

This unit describes methods for the construction and use of handheld particle bombardment devices for high-efficiency inoculation of intact plants with nucleic acids and viruses. The devices accelerate heavy metal particles coated with nucleic acids or viruses into plant tissues and are driven by pressurized gas. They are inexpensive to construct and use, and can be assembled in any laboratory.

Distribution and replication of the pathogenicity plasmid pPATH in diverse populations of the gall-forming bacterium Pantoea agglomerans.

Pantoea agglomerans has been transformed from a commensal bacterium into two related gall-forming pathovars by acquisition of pPATH plasmids containing a pathogenicity island (PAI). This PAI harbors an hrp/hrc gene cluster, type III effectors, and phytohormone biosynthetic genes. DNA typing by pulsed-field gel electrophoresis revealed two major groups of P.

The conserved FRNK box in HC-Pro, a plant viral suppressor of gene silencing, is required for small RNA binding and mediates symptom development.

The helper component-proteinase (HC-Pro) protein of potyviruses is a suppressor of gene silencing and has been shown to elicit plant developmental-defect-like symptoms. In Zucchini yellow mosaic virus (ZYMV), a mutation in the highly conserved FR180NK box of HC-Pro to FI180NK causes attenuation of these symptoms. At 5 days postinoculation and before symptoms appear, virus accumulation, HC-Pro protein levels, and viral short interfering RNA (siRNA) levels are similar for the severe (FRNK) and attenuated (FINK) strains.

Biolistic inoculation of plants with tomato yellow leaf curl virus DNA.

Tomato yellow leaf curl virus (TYLCV) full-length DNA was amplified by PCR and cloned into a bacterial plasmid. The cloned TYLCV DNA was excised from the plasmid, ligated and the resulting monomeric circular double-stranded TYLCV DNA was used to inoculate tomato (Solanum lycopersicom) and datura (Datura stramonium) plants by particle bombardment. The bombarded plants produced typical disease symptoms, similar to those produced following whitefly-mediated inoculation, albeit 5-7 days later than whitefly-inoculated plants.

Ultrasonic treatment stimulates multiple shoot regeneration and explant enlargement in recalcitrant squash cotyledon explants in vitro.

Ultrasonic treatment (0.5-2 min) stimulated multiple shoot regeneration to high levels in vitro from recalcitrant cotyledon explants of commercial squash (Cucurbita pepo L.) cultivars Ma'yan and Bareqet, on Murashige and Skoog [Physiol Plant 15:473-497, 1962] (regeneration) medium augmented with 4.

Magic-angle spinning NMR studies of cell wall bound aromatic-aliphatic biopolyesters associated with strengthening of intercellular adhesion in potato (Solanum tuberosum L.) tuber parenchyma.

Intercellular adhesion strengthening, a phenomenon that compromises the texture and the edible quality of potatoes (Solanum tuberosum L.), has been induced reproducibly by exposure to low-pH acetic acid solutions under tissue culture conditions. The resulting parenchyma tissues have been examined by solid-state nuclear magnetic resonance (NMR) in order to characterize the biopolymer(s) thought to be associated with this syndrome.

Transgenic cucumbers harboring the 54-kDa putative gene of Cucumber fruit mottle mosaic tobamovirus are highly resistant to viral infection and protect non-transgenic scions from soil infection.

Cucumber fruit mottle mosaic tobamovirus (CFMMV) causes severe mosaic symptoms and yellow mottling on leaves and fruits and, occasionally, severe wilting of cucumber (Cucumis sativus L.) plants. No genetic source of resistance against this virus has been identified in cucumber.