GenUS GP 20-02
Department of Genetics, Stellenbosch University
Project co-funded by The Department of Science and Innovation
Objectives and Rationale
Grapevine pinot gris virus (GPGV) is an apparently widespread, emerging virus internationally, but has not been reported in South Africa, but was recently intercepted in imported planting material. In this study we aim to determine whether this virus occurs in South Africa already.
A survey was conducted amongst 1) recently imported Vitis accessions from Europe and the USA, where GPGV has been found to be prevalent in recent times and 2) the Vitis germplasm collection at Nietvoorbij. Tests conducted for GPGV were ELISA with confirmation by PCR, and next generation sequencing.
Some of the imported Vitis accessions tested positive for GPGV by ELISA. This was confirmed by PCR and sequencing for four samples. Using NGS, GPGV was found absent in older Vitis accessions. GPGV ELISA tests are optimally done in spring with young leaf and petiole tissue or winter cane tissue.
Key Conclusion and Discussion
GPGV was found in recently imported material but not in older South African planting material. PCR detection by both ELISA and PCR was inconsistent and while infection was confirmed in 4 samples, many samples need further confirmation in the next spring sampling period.
Take Home Message for Industry
GPGV was found in recently imported plant material. Fortunately, these have not yet entered commercial production and relevant PIO’s are in the process of destroying infected material. This means the virus was intercepted and introduction into the South African grape industry prevented. The virus is difficult to study, and ELISA and PCR tests used in this study, are not fully reliable. It is recommended that DAFF test for this virus in all future imported grapevine tissue.