The uses of plant disease and insect collections are numerous but most importantly for taxonomic research and comparative biology. From a biosecurity perspective, these collections allow the development of specimen-based pest lists that are critical for resolving quarantine issues related to agricultural trade. Typically, plant disease and insect specimens are stored in a way that helps preserve the organisms' morphology but not necessarily their DNA. In the age of genomics, DNA sequencing has become one of the most important tools for identifying organisms and for biodiversity studies.

Research outcomes:

The major outcome of this project was the development of the Biosecurity Bank, a national reference collection of DNA samples from plant pathogens. In building the framework for the Biosecurity Bank, the existing Queensland Primary Industries and Fisheries Plant Disease Herbarium database was modified to include new fields for the archiving of information relating to DNA samples and clones. Using this database, it is now possible to link DNA samples to voucher specimens to facilitate taxonomic verification at a later date.

A new web site, www.biosecuritybank.com [5], was also developed to provide a portal to the DNA collection for the general scientific community to allow searches for samples of interest. The domain has been registered and the site is now live and hosted by Southern Cross University.

A method for storing DNA at room temperature was evaluated but unfortunately, this method did not preserve the DNA as well as storage in a freezer and therefore the latter has been adopted for maintenance of the collection.

Work has begun to populate the Biosecurity Bank with samples and so far 36 samples have been added including those from pathogens that cause citrus canker, tomato leaf curl and Panama disease.

Research implications:

Plant disease herbariums are reference collections of microorganisms (plant pathogens) that cause disease on crops, weeds and native plant species. Specimens held in these collections are important for taxonomic and biodiversity research but also are very important for biosecurity as they allow the development of specimen-based pest lists that are needed for resolving quarantine issues associated with agricultural trade.

Pressed plant specimens are the most common type of specimen held in plant disease herbariums, and provide a good record of the pathogen’s morphology. However,  as previously stated this method of storage is sub-optimal for preserving DNA.

In developing the Biosecurity Bank, the Australian scientific community is now provided with a reference collection of DNA samples from plant pathogens, which could potentially be used in all types of research projects, from the development of molecular diagnostic assays to ‘gene-mining’ for biologically-active compounds. To provide even greater assurance of the origin of the DNA, samples will be linked to voucher specimens held in Australian plant disease herbariums. 

Acknowledgements:

Funding from the Office the Chief Plant Protection Officer, Australian Department of Agriculture, Fisheries and Forestry, is gratefully acknowledged.