CRC for Plant Biosecurity - Rachel Meldrum

Banana Fusarium Wilt Tropical Race 4

CRICHTONA — Tue, 15 Nov 2011 00:58:36 +0000

Ninth Australian Banana Industry Congress

CRICHTONA — Tue, 02 Aug 2011 05:09:09 +0000

Rachel Meldrum represented the CRCNPB when she attended the Ninth Australian Banana Industry Congress during June 2011. Rachel presented her PhD research project on Fusarium oxysporum f.sp. cubense tropical race 4 (Foc TR4), a disease of great importance to Australian banana growers.

The information Rachel presented was related to improving the use of surface sterilants – used for decontaminating footwear, machinery and farm tools – thus the research was able to provide information regarding on-field management techniques for this destructive pathogen.

Rachel also participated in a Fusarium meeting at the Queensland Department of Employment, Economic Development and Innovation (DEEDI) at Maroochy Research Station. This meeting was held to discuss the future of banana Fusarium research and how Rachel's research may fit into the future development of this industry.

Participating in both the Fusarium meeting and Banana congress enabled Rachel to establish national and international collaborative networks which will benefit both current and future research.

Rachel said attendance at the Banana Congress gave her a greater understanding of the banana industry and the potential for future research activities and that discussing her research project enabled a greater understanding by industry on this pathogen.

Rachel said she anticipated that this interaction would lead to collaborations with people who also have an interest in the industry’s future.

Research to contain banana wilt infection

CRICHTONA — Wed, 04 May 2011 05:13:39 +0000

In less than a decade the Fusarium fungal pathogen has devastated the Northern Territory’s banana industry, although tough quarantine measures have so far protected the economically critical Queensland industry.

Fusarium wilt is a disease common to many horticultural industries; the form that strikes bananas is commonly known as Panama disease. The first major impact of this disease was observed in Panama (Central America), where between 1890 and the mid-1950s it destroyed 40,000 hectares of banana plantations with the variety ‘Gros Michel’ banana.

A Northern Territory Primary Industry group researcher and CRC for National Plant Biosecurity PhD candidate, Rachel Meldrum, says relatively little is known about the Fusarium strain causing the problem in the Northern Territory. She says tropical race 4 of Fusarium oxyporum f. sp. cubense (Foc TR4) was detected in the Northern Territory in 1997, although the exact source of the infection remains unknown.

It was identified in a banana farm on the outskirts of Darwin and is genetically similar to the strain that devastated ‘Cavendish’ plantations developed for export in south-east Asia in the early 1990s. “The industry here was looking to expand at the time, to fill an offseason niche in production,” Ms Meldrum says.

“Production peaked in 2000, with 7,000 tonnes of production valued at $13 million. But by 2009 the industry was reduced to one-third of its original value, worth about $4 million, and most of the major growers in the Territory had left the industry,” she says.

Ms Meldrum’s PhD project aims to create a better understanding of the Foc TR4 pathogen and how it spreads, and to develop more effective control strategies.

She says there are four races of Fusarium oxyporum f.sp. cubense (Foc) known to exist, and three are pathogenic to bananas. Race 1 causes disease in ‘Lady Finger’ and ‘Gros Michel’ varieties and race 2 affects ‘Bluggoe,’ a cooking banana variety.

Race 3 is pathogenic to decorative floral and landscaping plants of the Heliconia species.

Foc Tropical race 4 is pathogenic to all commercial banana cultivars, including Cavendish, which make up 95 per cent of the $350 million Australian crop.

Race 4 is further divided: subtropical and tropical race 4. While all races of Foc are important to the Australian banana industry, the threat of Foc tropical race 4 is considered the greatest; it kills otherwise healthy plants quickly and can spread rapidly on plantations.

“We know it is a soil-borne pathogen, so we already have some recommendations for growers about steps they can take to prevent it spreading,” Ms Meldrum says.

Chief among these is the use of tissue-cultured banana plants to prevent the spread of infection. Ms Meldrum says that while it is possible for banana growers to regenerate their primary banana plants from suckers or daughter plants, the transportation of soil adhering to the plant can also transfer the pathogen.

Ms Meldrum is also investigating the role of the banana borer weevil as a possible disease vector. The borer is not a big problem for growers, particularly once banana plants are well established, but it can travel 30 metres in a day and has the potential to transfer infected soil between plants and crops.

Greater control of the borer may help eliminate one potential source of spread. Other quarantine measures being implemented include fencing for banana plantations to prevent wild animals transferring disease through the transfer of soil, and the use of washdown facilities and chemical washes.

As part of her research Ms Meldrum hopes to learn more about the epidemiology of the Foc TR4 pathogen, including how long it survives in the soil. “It is believed to survive in the soil for decades and we need to work out how it survives – does it use alternative host plants, or does it have hard spore cases that protect it?”

Tests are being conducted on two weeds common in the Northern Territory – Mission Grass and Gamba Grass – as possible alternative host plants that may be allowing the pathogen to survive long periods in the soil. Farmers also commonly grow sorghum as a cover crop on cleared land and this will also be tested as a possible host for Foc TR4.

Ms Meldrum says some banana species and cultivars with resistance to TR4 have been identified. However, none are acceptable as a commercial replacement for the Cavendish cultivars. “Our best long-term response may be to improve resistance in the commercial varieties,” she says.

To show its support to the banana industry, the Cooperative Research Centre for National Plant Biosecurity is providing sponsorship for the ninth Australian Banana Industry Congress at the Hyatt Regency on the Sunshine Coast from 1-4 June 2011. For more information, visit the banana congress website.

International Fusarium Laboratory Workshop

VANMEURSA — Fri, 02 Oct 2009 03:48:49 +0000

Rachel Meldrum participated in the 2008 International Fusarium Laboratory Workshop. She attended the workshop to receive training in the latest morphological, genetic and molecular techniques available for the identification and characterisation of Fusarium strains.

Participation in the Fusarium Laboratory Workshop greatly enhanced Rachel’s skills in the field of plant pathology. Specifically her biosecurity skills were expanded, enabling the identification of a range of Fusarium species using different techniques. The techniques acquired from participation in the workshop included up-to-date molecular techniques as well as microscopy. These techniques will be applied to conduct research and diagnose exotic plant pathogens such as Fusarium. Fusarium Wilt disease of banana caused by Fusarium oxysporum f. sp. cubense tropical race 4 is considered to be one of the most devastating plant pathogens. At present, this fungal pathogen Foc TR4, is found in the Northern Territory and is exotic in other parts of Australia.

As part of her PhD project CRC60097: Fusarium TR4 - PhD, Rachel will isolate a range of Fusarium species, which will be morphologically similar or identical. The detailed morphological analysis information provided during the workshop will enable her to use microscopy to differentiate between morphologically similar strains. However, to differentiate between morphologically identical strains, Rachel will be able to employ newly acquired molecular tools to further the analysis for strain identification.

The workshop was conducted by six international Fusarium experts who introduced and trained participants in general techniques as well as providing information on common Fusarium species. By establishing an international collaborative network, long term collaborations will include future communications with experts from Malaysia, Norway, USA, Korea and Italy.

Eighth Australian Banana Industry Congress

VANMEURSA — Fri, 02 Oct 2009 00:34:00 +0000

Rachel Meldrum represented the CRC at the Eighth Australian Banana Industry Congress, where she presented her PhD research project on Fusarium oxysporum f.sp. cubense tropical race 4 (Foc TR4). Rachel’s presentation highlighted that Fusarium wilt of banana caused by Foc TR4 is considered to be one of the most devastating plant pathogens while bananas are the most important tropical crop in Australia. Rachel also discussed how her research on Foc TR4 will help develop knowledge which is currently unavailable. The presentation created awareness and interest amongst industry and researches of the potential impacts of Foc TR4.

After the Congress Rachel participated in a meeting at Queensland Primary Industry and Fisheries (QPI&F) in Toowoomba, where another Fusarium oxysporum (Fov) was discussed, throughout these discussions Rachel found the research done on Fov would be useful to her as Foc and Fov have many similarities. Rachel made valuable contacts at QPI&F who will be able to assist in her research.

The Congress and meeting with QPI&F enabled Rachel to establish national collaborative networks which will benefit both her current and future research. It also gave her a greater understanding of the industry as a whole and the many research and development activities being undertaken. Finally, it gave perspective on how her research fits into the future development of the industry.

The national collaboration of Foc TR4 research will improve the status of Australia’s plant biosecurity system. This communication created an extensive industry awareness regarding the seriousness of Foc TR4, which has the potential for future financial investment in Foc TR4 research.

The travel also provided the opportunity to communicate with the Australian banana industry, the potential end users of this PhD research project, CRC60097. Discussions with industry ensure the research project outcomes reach the identified target end users.