vADW 2024-25 – Webinar 1: Plant Virology

The National Plant Biosecurity Diagnostic Network’s (NPBDN) virtual Annual Diagnostics Workshop (vADW) 2024-25 was hosted on Wednesday 13 November. The first webinar centred on plant virology with a focus on tobamoviruses, especially the Tomato brown rugose fruit virus (ToBRFV). It attracted expert speakers from Australia, Europe, and the United Kingdom.

Australian insights on tobamoviruses

Dr Fiona Constable from Agriculture Victoria Research, who chairs the High Throughput Sequencing Working Group (HTSWG) within the Subcommittee of Plant Health Diagnostics (SPHD), opened the webinar. She provided updates on the HTSWG’s progress towards establishing high throughput sequencing (HTS) standards, a key element of plant health diagnostics for both Australia and New Zealand.

Dr Constable provided a background on tobamoviruses, some of which are estimated to have existed for 110 million years. In Australia, there is only one native tobamovirus (yellow tailflower mild mottle virus) found in wild Solanaceae, with nine naturalised species such as tomato mosaic virus (ToMV). To prevent tobamovirus incursions, Australia conducts Solanaceae and Cucurbitaceae seed testing, primarily in Victoria and New South Wales.

Dr Constable also highlighted the role of the International Committee on Taxonomy of Viruses (ICTV) in standardising virus classification. ICTV guidelines ensure virus names are globally consistent, benefiting regulatory, clinical, and agricultural applications.

ToBRFV’s spread in Europe

Prof Rene van der Vlugt from Wageningen University and Research provided an update on ToBRFV’s impact across Europe. The virus, first detected in Jordan and Israel around 2014–15, infects tomatoes, capsicums, and eggplants, and can spread to some weed species. Symptoms of ToBRFV include leaf blistering and mottling in tomato fruit. Mixed infections with other viruses, such as pepino mosaic virus (PepMV), complicate its detection and control. Prof van der Vlugt noted that ToBRFV eradication is no longer feasible in some European regions, where efforts now focus on containment through clean planting materials and routine testing.

UK containment strategies

Dr Adrian Fox from Fera Science in the United Kingdom outlined containment challenges. ToBRFV spreads through mechanical contact, including plant-to-plant transfer, handling, and even bumblebee activity. Since 2018, the UK has implemented protocols to manage ToBRFV, though the virus’s resilience complicates eradication. ToBRFV can survive on surfaces for extended periods – up to two hours on skin and six months on hard materials – which highlights the need for strict hygiene practices. Surveillance data show five infected sites in southern England, underscoring the virus’s persistence and need for rigorous biosecurity.

Innovative student research

Two PhD students from La Trobe University also presented new diagnostic methods:
• Gopi Koladiya developed a dissolving microneedle patch for rapid nucleic acid extraction in strawberries, aiming to simplify virus detection.
• Kamalpreet Kaur shared research on grapevine virus diagnostics, including the grapevine Pinot gris virus (GPGV) and grapevine red blotch virus (GRBV). Her work highlighted the need for improved diagnostics to support Australia’s grape industry.

Stay informed about this and other events

This was the first of four webinars in the series, which will run until April 2025.
If you would like to watch the recording or register for future ADW events, please visit the NPBDN website and apply to become a NPBDN member.

Upcoming workshops in the 2024-25 ADW series will include topics on Bacteriology, Mycology and Invertebrate plant pests. NPBDN is currently seeking expressions of interest for PhD student presenters in these topics. Click here to submit an abstract.

Keep and eye out for information in early 2025 on the upcoming virtual Annual Surveillance Workshop in May / June 2025.