Ground Cover North : Ground Cover 055 April-May 2005 - North
By BRAD COLLIS n The ability to analyse specific genetic traits such as salinity tolerance and incorporate them into new crop lines may be significantly advanced following the development of a rice library built around the green fluorescent protein gene, GFP. The GFP gene has proved a powerful biological tool since American researchers first cloned it in the early 1990s. It makes plant tissues fluorescent when viewed under ultra-violet light. Dr Alex Johnson, from the Australian Centre for Plant Functional Genomics (ACPFG) in Adelaide, has developed 13,000 transgenic rice lines harbouring a GFP configuration called an ‘enhancer trap’, that allows researchers to identify genes that are active in specific cell types. When the tissue is fluorescent, it means that the GFP gene is expressed. The fluorescence pattern indicates the activity of individual rice genes. Once interesting genes have been identified, they can be used to express any gene of interest in a specific cell type – such as leaf or root tissue. This cell-specific approach to expressing new genes is an important advance on more conventional strategies that result in genes being expressed While acknowledging that GM crops were still under attack from lobby groups trying to stop commercial releases, Dr Ripley was optimistic that a wider use of GM technology with direct consumer benefits would eventually diminish consumer opposition. He felt the future, however, was becoming clear through the work of scientific collaborations such as the Napus 2000 Project in Europe, which recently produced genetically modified linseed plants that accumulate very-long-chain polyunsaturated fatty acids (PUFA). This breakthrough, in 2004, is regarded by scientists as showing how genetic engineering of agronomically important species can benefit human health and nutrition, and the environment. PUFA, or essential fatty acids such as the omega-3 fatty acids found in fish oil, are recognised as important components of a healthy human diet. Increased consumption has been linked to a reduced risk of heart disease and other health benefits, including protection against inflammatory diseases like arthritis, irritable bowel syndrome, some cancers and the promotion of healthy brain and eye development in infants. Developing transgenic crops that can produce these essential fatty acids is seen by some scientists as a way to resolve nutritional issues, and overcome the dangers of pollutants in fish and the depletion of world fisheries. While crops such as canola, safflower and linseed already accumulate PUFA such as linoleic acid and alpha-linoleic acid and may metabolise in the body, the process is slow and inefficient compared to eating fish oils. Dr Ripley said recently patented discoveries by Bioriginal Food & Science Corp in Canada of the enzymes responsible for the development of omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), could be a in all of a plant’s cell types. Dr Johnson’s approach allows scientists to narrow their research to areas of specific interest – to monitor, for example, how specific parts of a plant, such as the root epidermis, respond to the presence of a new gene or genes. The reason rice was used for the library is that it is a functional genomic model for other cereals like wheat and barley and for forage grasses. It is also vital as the staple food for half the world’s population. Sequencing of the rice genome was completed in 2002 and shows extensive similarity to other cereal genomes. This means genetic information that has been gathered about rice can often be applied to cereals. Dr Johnson says an early application of the library at the ACPFG will be to facilitate research into salinity tolerance mechanisms. Researchers will be able to concentrate their efforts on the manipulation of sodium transport genes in the root, a key area of interest for the development of salt-tolerant cereal crops. ∆For more information: Dr Alex Johnson, alex.johnson@acpfg. com.au, or visit http://plantscience. acpfg.com.au/project/detail/36 significant step towards transgenic grains becoming a new source of important nutrients for people. He said the gene responsible for these enzymes can be cloned, enabling them to be introduced into oilseed varieties. Dr Ripley said that while much of this research was in its early stages, it was important for the Australian grains industry to avoid falling behind in the use of transgenic technologies, and biotechnologies generally. He said GM technologies would be crucial to developing grain varieties that were able to produce increased yields and grain quality under deteriorating environmental conditions. In Australia, CSIRO researchers are also hoping to have linseed oil, soybean oil and canola oil join fish as providers of long-chain omega-3 fatty acids. The CSIRO’s ‘heart healthy grains’ project is part of its Food Futures Flagship aimed at boosting Australia’s agrifoods sector and further lifting its international competitiveness. Dr Allan Green, who is leading the team, says GM technology is the key to identifying and incorporating into grains the genes responsible for producing omega-3 fatty acids in the micro-algae that fish feed on. Dr Green says that once this is achieved, the research could take two different paths. One would be omega-3 fatty acids in feedgrains to produce poultry, pig meat, lamb and beef rich in omega-3. The other path would be specially enriched omega-3 grain for human consumption. He says that omega-3 fatty acids would be protected in grain, which would allow products like wholegrain bread to be a suitable delivery system. ∆For more information: Dr Van Ripley, email@example.com GENE LIBRARY TO LIFT CROP RESEARCH New light on plant tissues: Dr Alex Johnson at the Australian Centre for Plant Functional Genomics. PHOTO: BRAD COLLIS GM CROPS CHANGING DIRECTION FROM PAGE 1 News 3 APRIL/MAY 2005 GROUND COVER Join GGA now and receive a FREE book! Become a Grain Growers Association Gold Member for $50 for three years and receive The Workshop Companion – the latest publication from the Kondinin Group (rrp $49.95). Grain Growers Association is Australia’s largest grains organisation, working at the forefront of the industry in leading debate and discussion, and providing information to pave the way for the future of a sustainable and viable Australian grains industry. 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