First detection and tracing of grapevine red blotch virus (GRBV) in Australia using tiled amplicon sequencing.

Grapevine red blotch virus (GRBV; species Grablovirus vitis, genus Grablovirus, family Geminiviridae) poses a significant threat to viticulture worldwide, impacting grapevine health and wine quality. Here, we report the first detection and tracing of GRBV in Australia and provide a summary of a subsequent survey to determine the extent of GRBV distribution in Western Australia. Additionally, the study introduces a tiled amplicon sequencing method, which, when combined with long-read nanopore sequencing, enables rapid GRBV genome sequencing. Our analysis suggests a single introduction of GRBV from North America to Australia through the state of Victoria and subsequently to Western Australia. Finally, this study provides insight into the epidemiology of GRBV, based on strain variation and distribution, which is a crucial step in supporting an emergency biosecurity response and implementing effective control measures to safeguard the sustainability of the wine industry in Australia.