Combining traditional and contemporary diagnostics to protect industry

Fast and reliable diagnosis of banana pests is vital for successful containment and eradication of diseases which threaten our industry. Using a combination of traditional and molecular, or DNA-based diagnostic methods, scientists are able to quickly diagnose many of the serious exotic banana diseases.

The successful eradication of black Sigatoka from Tully during 2001 is an excellent example where scientists have drawn on a mix of traditional and contemporary methods to solve a problem. Plant pathologists at the Centre for Tropical Agriculture (DPI&F Mareeba) used specialist skills in leaf symptomology to make an initial diagnosis before using molecular techniques to confirm the identity. In this case, the diagnostic fungal structures used to differentiate yellow and black Sigatoka had been washed away by high rainfall. Fortunately, a DNA test was available which could be used to confirm the identity of fungi growing on the banana leaf surface.

The molecular test for black Sigatoka, along with many other tests including Moko disease, Tropical Race 4 Fusarium wilt and Banana Bunchy Top disease, were generated in collaborative Horticulture Australia funded projects within the Cooperative Research Centre for Tropical Plant Protection (CRCTPP). The CRCTPP enjoyed a long-running association with the Australian banana industry during its 14 year operation. Closure of the CRCTPP in June 2006, resulted in a dramatic decrease in expertise available for delivery, maintenance
and development of further assays.

New funding for banana disease diagnostics

The Australian Banana Growers Council, together with Horticulture Australia, recognise the need to maintain the molecular diagnostic capability for detection, surveillance and eradication of diseases which are economically important to the Australian banana industry. A new project to address this requirement has commenced: BA06007 Strengthening disease detection, diagnosis and surveillance in the Australian banana industry.

Objectives of this project include: (1) delivery of existing diagnostic assays for target diseases (Fusarium wilt, Bacterial wilt, banana virus threats, Eumusae leaf spot) and maintenance of diagnostic controls for quick deployment of these assays, (2) development of new diagnostic assays for target exotic threats (eg. Cavendish-competent banana freckle disease) and (3) improved industry liaison and communication with respect to disease surveillance and diagnosis.

Who is staffing the new project?

Dr Juliane Henderson is the diagnostician appointed to this project. Dr Henderson, a CRCTPP scientist for nine years, has been associated with the banana industry since 2000. Juliane is a trained molecular plant pathologist with experience in fungal, bacterial and viral pathogens. Prior to bananas, Juliane has worked in the sugarcane and papaya industries. In 2001, she led the diagnostic team who developed and delivered the DNA-based assay for black Sigatoka. Since then, Juliane and her colleagues at the CRCTPP, have worked closely with DPI&F plant pathologists to develop advanced molecular technologies for banana leaf spot diseases. As a result of this collaboration, the Australian banana industry now has the most advanced diagnostic assays for Sigatoka leaf diseases available worldwide.

This project will continue to foster close collaboration between scientists with complementary skills. We have already seen significant achievements in diagnostic development through the combination of specialist skills of plant pathologists and molecular pathologists. It will also encourage greater communication between scientists, growers and other industry personnel, which will improve our surveillance, detection and eradication capabilities.

Watch this space for updates on the project, including information on new exotic diseases and pests of significance.

If you would like more information about the project, please contact Juliane Henderson on 07 3896 9348 or email juliane.henderson@dpi.qld.gov.au