Dr Alexander Piper1, Dr Mark Blacket1, Dr Isabel Valenzuela1, Dr Junji Miyazaki1, Dr Catherine Clarke1, Dr J. Paul Cunningham1,2

1Agriculture Victoria Research, AgriBio Centre, Bundoora, Australia, 2School of Applied Systems Biology, La Trobe University, Bundoora, Australia

Biography:

Dr. Alexander Piper is a research scientist at Agriculture Victoria, specialising in applied genomic studies of agriculturally important insect species. His current research focuses on developing new molecular and bioinformatic approaches for understanding dispersal, spread, and adaptation of invasive insects to novel environments. He earned his PhD from La Trobe University, with a thesis on “Genomic Bio-surveillance of Insect Pests”. Dr. Piper has authored 17 scientific papers in the fields of genomics, molecular entomology, and chemical ecology, and has contributed to shaping Australian and European standards for the application of high-throughput sequencing technologies in plant pest diagnostic laboratories. He currently leads the fine-scale genomics research component for the Hort Innovation funded Fresh and Secure Trade Alliance project and is a partner investigator on the ARC Training Centre in Plant Biosecurity, collaborating with industry, government, and universities to protect Australian agriculture from pests and diseases.

Abstract:

Grapevine phylloxera, Daktulosphaira vitifoliae, represents one of the most significant biological invasions in recorded history, causing widespread devastation to vineyards worldwide. Introduced to Australia in the late 1800s, its distribution has remained confined to regions of Victoria and New South Wales through strict quarantine regulations and farm-gate hygiene practices. Within these ‘phylloxera infested zones’, however, effective management requires replanting entire vineyards with resistant rootstocks derived from North American Vitis species that coevolved with the pest. Selecting appropriate rootstocks requires knowledge of the genotypic composition of clonally reproducing phylloxera present in each vineyard. However, the past few decades have seen the recognition of highly virulent ‘superclones’ and detection of substantial new genotypic diversity, posing serious risks to viticultural production. In this study we sequenced the complete genomes of seven key Victorian phylloxera strains, each exhibiting unique virulence profiles and geographic distributions. Population genomic analysis of these strains alongside data from 18 international populations suggests at least two separate introductions into Australia: one via Europe and another directly from North America. These distinct introduction pathways, and the contrasting co-evolutionary histories with native Vitis species implied by them, are likely to explain the differing virulence and prevalence of these strains within Australian vineyards. Our dataset serves as a foundation for future research into the genomic architecture underlying virulence phenotypes and supports the development of new genotyping approaches that better reflect virulence differences among strains.