Prevalence and genetic variability of grapevine virus A in Turkish autochthonous grapevine varieties.

This work describes the first molecular characterization of grapevine virus A (GVA) in Turkish grapevine varieties based on the coat protein gene. RT-PCR detection revealed a high infection rate of GVA in two major viticultural areas, Eastern Mediterranean (EM) and Southeast Anatolia (SEA). The number of infected varieties was higher in SEA, where very ancient and traditional cultivars are in use and no foreign grapevine material has been introduced. High nucleotide and amino acid sequence similarity were seen between the Turkish GVA isolates and the reference isolates in group I and II. The viral isolates from the same location and cultivars were not phylogenetically related.

2020 taxonomic update for phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

In March 2020, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. At the genus rank, 20 new genera were added, two were deleted, one was moved, and three were renamed. At the species rank, 160 species were added, four were deleted, ten were moved and renamed, and 30 species were renamed. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

High prevalence of poleroviruses in field-grown pepper in Turkey and Tunisia.

Open-field pepper crops were sampled in 2011 in Turkey and Tunisia and surveyed for the major pepper-infecting viruses. As expected, potato virus Y and cucumber mosaic virus (in both countries), and tobacco etch virus (in Turkey only) were quite frequent. However, poleroviruses were the most common viruses, with prevalences above 70 %. Partial sequence analyses revealed the occurrence of poleroviruses resembling either beet western yellows virus (BWYV) or pepper vein yellows virus in the sampled areas, with BWYV being predominant in Turkey but in the minority in Tunisia. Poleroviruses should therefore be taken into account in disease control of pepper crops in the Mediterranean area.

A new emaravirus discovered in Pistacia from Turkey.

High throughput sequencing was performed on total pooled RNA from six Turkish trees of Pistacia showing different viral symptoms. The analysis produced some contigs showing similarity with RNAs of emaraviruses. Seven distinct negative-sense, single-stranded RNAs were identified as belonging to a new putative virus infecting pistachio. The amino acid sequence identity compared to homologs in the genus Emaravirus ranged from 71% for the replicase gene on RNA1, to 36% for the putative RNA7 gene product. All the RNA molecules were verified in a pistachio plant by RT-PCR and conventional sequencing. Although the analysed plants showed a range of symptoms, it was not possible to univocally associate the virus with a peculiar one. The possible virus transmission by mite vector needs to be demonstrated by a survey, to observe spread and potential effect on yield in the growing areas of the crop.

Detection of Xylella fastidiosa from resistant and susceptible grapevine by tissue sectioning and membrane entrapment immunofluorescence.

Immunofluorescence detection was performed by tissue sectioning and membrane entrapment of Xylella fastidiosa from the inoculated hybrid selection F8909-08 (Vitis rupestris A. de Serres x V. arizonica/candicans b43-17; resistant) and Chardonnay (susceptible). In both techniques, tissue sections and bacteria-trapped polycarbonate membranes were incubated with specific polyclonal IgG and stained with fluorescein isothiocyanate (FITC)-conjugated IgG from rabbits to X. fastidiosa cells. The stained preparations were observed by fluorescence microscopy. Rapid identification of the bacteria within 3 weeks post inoculation (wpi) was possible in thin cross sections of the petioles, which allowed penetration of the specific antibody. Examination of the bacteria over time was also possible, and allowed observation of bacterial multiplication and invasion of xylem vessels. The membrane entrapment technique was able to isolate bacteria at low concentrations in infected but asymptomatic plants.

The role of urtica dioica (urticaceae) in the prevention of oxidative stress caused by tourniquet application in rats.

Tourniquets are used in extremity surgery and provide a relatively bloodless field, thereby minimizing blood loss and helping identify the vital structures. However, they may cause an ischemia-reperfusion injury with potentially harmful local and systemic consequences. Many therapeutic effects such as diuretic, natriuretic, hypotensive, anti-rheumatic, anti-prostatic, and in-vitro anti-oxidant effects of the Urtica dioica (UD) have been determined. In the present study, we aimed to investigate the potential role of UD plant for prevention of oxidative stress in muscle tissues generated by tourniquet application in rats. Wistar rats were used in this study. The UD extract or 1.15% KCl aqueous solution, in which UD leaf samples were homogenized, was given to each group of eight rats once a day for 5 days through an intraesophageal canule. No treatment was applied to untreated group. Tourniquets were applied to the left posterior limb of rats for 1 or 2 h followed by a reperfusion period of 1 h. After the ischemia and reperfusion, the rats were killed with a high dose of anesthetic drug, and malonyldialdehyde (MDA) levels were measured in their tibialis anterior muscles. Basal MDA levels were obtained from tibialis anterior muscles of 8 control rats, which were not exposed to ischemia. MDA levels were lower in the UD-treated rats than those in untreated and KCl-treated rats after either 1 or 2 h of ischemia and 1 h reperfusion. These results indicate that UD has a potential antioxidant effect on ischemic muscle tissues.