Vitis rupestris is used as rootstock or to obtain hybrids with Vitis vinifera, due to its resistance to certain pathogens. Its resistance mechanisms are poorly understood, while it is known that stilbene neo-synthesis is a central defense strategy in V. vinifera. In the present study, the response to methyl jasmonate (MeJa) and light treatment in terms of stilbene biosynthesis and the expression of genes involved in polyphenol biosynthesis was investigated in V. vinifera and V. rupestris cells. The two species exhibited a similar constitutive stilbene content [2.50-2.80 mg g dry weight (DW)], which greatly increased in response to elicitation (8.97-11.90 mg g DW). In V. vinifera, continuous light treatment amplified the effect of MeJa, with a stilbene production that had never previously been obtained (26.49 mg g DW). By contrast, it suppressed the effect of MeJa in V. rupestris. Gene expression was consistent with stilbene production in V. vinifera, whereas discrepancies were recorded in V. rupestris that could be explained by the synthesis of stilbenes that had never before been analyzed in this species.

No abstract

High-throughput sequencing (HTS) technologies and bioinformatic analyses are of growing interest to be used as a routine diagnostic tool in the field of plant viruses. The reliability of HTS workflows from sample preparation to data analysis and results interpretation for plant virus detection and identification must be evaluated (verified and validated) to approve this tool for diagnostics. Many different extraction methods, library preparation protocols, and sequence and bioinformatic pipelines are available for virus sequence detection. To assess the performance of plant virology diagnostic laboratories in using the HTS of ribosomal RNA depleted total RNA (ribodepleted totRNA) as a diagnostic tool, we carried out an interlaboratory comparison study in which eight participants were required to use the same samples, (RNA) extraction kit, ribosomal RNA depletion kit, and commercial sequencing provider, but also their own bioinformatics pipeline, for analysis. The accuracy of virus detection ranged from 65% to 100%. The false-positive detection rate was very low and was related to the misinterpretation of results as well as to possible cross-contaminations in the lab or sequencing provider. The bioinformatic pipeline used by each laboratory influenced the correct detection of the viruses of this study. The main difficulty was the detection of a novel virus as its sequence was not available in a publicly accessible database at the time. The raw data were reanalysed using Virtool to assess its ability for virus detection. All virus sequences were detected using Virtool in the different pools. This study revealed that the ribodepletion target enrichment for sample preparation is a reliable approach for the detection of plant viruses with different genomes. A significant level of virology expertise is needed to correctly interpret the results. It is also important to improve and complete the reference data

A one‐step reverse transcription–polymerase chain reaction (RT–PCR) protocol was developed and used for the detection of Strawberry latent ring spot virus (SLRSV) in leaves of olive trees in Italy. The protocol was used to test for infection in samples from 87 trees and to correlate infection with leaf symptoms. SLRSV was found only in olives grown in Central Italy (the Marche and Umbria regions) and was detected in c. 15% of leaf samples. Most infected plants had narrow and twisted leaves, symptoms which seemed to occur in specific cultivars. The one‐step RT–PCR protocol is very rapid and sensitive and has the potential to be used on a mass scale for the diagnosis of SLRSV in olive. This virus should be considered an important pathogen in olive trees, even if its distribution in the field seems to be limited to well defined areas.

No abstract