This project will examine the diversity and biology of tomato-infecting geminiviruses from Australia and south-east Asia. In addition, novel strategies for the multiplexed, hierarchical detection and diagnosis of plant viruses will be developed for the improvement of plant virus incursion detection and management capacities.

What is the biosecurity problem?

Tomato leaf curl disease, caused by a complex of geminivirus species in the genus Begomovirus, is widely regarded as the most significant constraint to tomato production worldwide. Despite quarantine measures, a recent incursion of Tomato yellow leaf curl virus (TYLCV) was detected in south-east Queensland. TYLCV is now causing significant losses in tomato production in regions surrounding Brisbane and Bundaberg.

Given that the insect vector of TYLCV, the whitefly Bemisia tabaci, is present in Australia, this disease poses a huge risk for establishment and spread.

Improved virus detection and disease management strategies are needed to prevent the establishment and spread of TYLCV in Australia, and also to prevent further incursions of geminiviruses. New diagnostic strategies and technologies, focussed on hierarchical and multiplexed detection, could enable the simultaneous detection of endemic, exotic and newly occurring Geminivirus species that arise through recombination. More efficient diagnostics would greatly enhance disease surveillance and management capabilities.

The main outputs of this project are to:

• train an Australian post-graduate (PhD) student in plant virology and molecular diagnostics
• assess the recent incursion of Tomato yellow leaf curl virus in Australia
• assess the genetic diversity and biological features of geminiviruses from Australia and south-east Asia
• develop and validate diagnostic assays for a range of geminiviruses posing either a domestic or international quarantine threat, and
• evaluate a novel diagnostic platform, OptoPlex^TM nanobeads, for the multiplexed hierarchical detection of plant viruses.

Who will be the end-users of this research?

• State and Territory Department of Primary Industries
• Australian Quarantine and Inspection Service
• Universities
• CSIRO, and
• Commercial diagnostic laboratories.