Detection and identification of viruses in Nucleus material
PROJECT TITLE: Detection and identification of viruses in Nuclear material
Project leader: Gerhard Pietersen (Stellenbosch University)
Contact: gpietersen@sun.ac.za
Duration: 31 December 2019 to 31 December 2022
Problem identification and project objectives:
Certification schemes worldwide are used to preventing the spread of pathogens via planting material. While the one-Vitis certification scheme of South Africa requires tests for specific viruses of grapevines, a large number of viruses, known to infect grapevines globally, do not need to be tested for, within the scheme. It is unknown whether any of these viruses are present in nuclear plant material and in what incidence they occur. In this proposal we wish to determine whether nuclear material used within the South African table and wine grape industries are free of viruses, and if not, to identify those viruses still present in such material as a first step towards eliminating or managing them, in accordance with the fundamental objectives of a certification scheme.
More than 70 viruses occur on grapevines worldwide (Martelli, 2017). Only GFLV, GLRaV-1,2 and -3, GFkV, GVA and GVB must be tested for in nuclear plants of the One-Vitis certification scheme. PIO’s voluntarily do independent tests against more viruses. These tests do not identify all potential viruses occurring. NGS allows, for the first time, the detection of all viruses within a plant. Viruses in nuclear material is potentially of great concern, even if it results in a small adverse effect, as thousands of progeny plants are derived from such plants, with the majority then being infected. The cumulative effect of a virus on thousands of derived plants is likely economically significant even when the effect per vine is small. This risk unquantified, as no local nuclear plants have been subjected to virus-wide analysis to the applicants knowledge and we do not know which viruses, if any, occur in nuclear material. The NGS system, once developed here can be applied in the certification scheme on a routine basis in future. With decreased margins of profitability within the South African wine and table grape industries any industry-wide improvement in quality and quantity of the final crop has value for the country. Martelli, G.P., 2017. Overview on grapevine viruses, viroids, and the diseases they cause. Chapter 2 In “Grapevine Viruses: Molecular Biology, Diagnostics and management.|” Eds. Meng, Martelli, Golino and Fuchs. Springer, Switzerland