Viroids, the smallest known pathogens, unable to encode any proteins, can cause severe diseases in their host plants. One of the proposed mechanisms of their pathogenicity includes silencing the host's genes via viroid-derived small RNAs, which are products of the host's immune response to the viroid's double stranded RNA. Humulus lupulus (hop) plants are hosts to several viroids; two of them, ...

The satellite RNA of tobacco ringspot virus (sTobRV) undergoes self-catalysed cleavage during replication. A plasmid for in vitro expression of sTobRV has been constructed and used to obtain a library of mutagenized sTobRV sequences. Screening of these mutants has allowed precise definition of the sequences required for (+) and (-) strand cleavage. The sequences and RNA structures associated wi...

The identification of viroid-derived small RNAs (vd-sRNAs) of 21 to 24 nucleotides (nt) in plants infected by viroids (infectious non-protein-coding RNAs of just 250 to 400 nt) supports their targeting by Dicer-like enzymes, the first host RNA-silencing barrier. However, whether viroids, like RNA viruses, are also targeted by the RNA-induced silencing complex (RISC) remains controversial. At th...

A novel virus-like sequence from grapevine was identified by Illumina sequencing. The genomic organization was most similar to that of members of the genus Fabavirus Polyproteins RNA-1 and RNA-2 of the virus tentatively named grapevine fabavirus (GFabV) shared 34 to 23% sequence identities with Broad bean wilt virus 2 (BBWV2), respectively. GFabV was successfully graft transmitted to Vitis vini...

Next-generation sequencing (NGS) has been applied to plant virology since 2009. NGS provides highly efficient, rapid, low cost DNA, or RNA high-throughput sequencing of the genomes of plant viruses and viroids and of the specific small RNAs generated during the infection process. These small RNAs, which cover frequently the whole genome of the infectious agent, are 21-24 nt long and are known a...

Replication of viroids, small non-protein-coding plant pathogenic RNAs, entails reiterative transcription of their incoming single-stranded circular genomes, to which the (+) polarity is arbitrarily assigned, cleavage of the oligomeric strands of one or both polarities to unit-length, and ligation to circular RNAs. While cleavage in chloroplastic viroids (family Avsunviroidae) is mediated by ha...

During the study on endophytic fungi of grapevine (Vitis vinifera L.), 655 fungal isolates were obtained and studied taxonomically. Based on morphological and ITS sequences data, 15 species belonging to 10 genera including Alternaria brassicicola, A. chlamydospora, A. malorum, A. atra, Arthrinium phaeospermum, A. sacchari, Aspergillus nidulans, A. wentii, Beauveria bassiana, Cheatomium elatum, ...

• The bell-pepper aroma typical of Cabernet Sauvignon and Sauvignon blanc has been correlated with the corresponding concentration of isobutyl-methoxypyrazine (IBMP). However, the term “vegetal” can include aromas other than bell-pepper. For example, many sulfur-containing compounds can elicit vegetal notes (e.g. asparagus, cooked corn, boxwood, rubber), and so can the norisoprenoid class of co...

Background. Grapevine leafroll disease is one of the most widespread viral diseases in vineyards, affecting nearly all grape and wine regions in the world. Infection causes yield losses, ripening delays, and alters fruit chemistry, including lowering soluble solids and increasing titratable acidity. The viruses associated with leafroll disease are transmitted through propagation of infected mat...