Growth Industry

By Melissa Trudinger
Monday, 15 April, 2002



Plant genetics is a driving force in agricultural biotech in Australia, affecting the commercial crop industries, horticulture, forestry and viticulture. Even livestock industries have plant biotechnology programs to develop improved pasture crops.

The original biotechnologists were farmers who domesticated plants and animals for human use as sources of food and clothing. These primitive biotechnologists and the generations of farmers who came after them used the principles of genetics to select for traits of interest.

Traditional plant breeding methods, however, take a long time.

According to Prof Peter Langridge, Research Director of the CRC for Molecular Plant Breeding (CRCMPB), the average length of time needed to breed a new cereal grain variety is 14 years. By taking advantage of molecular marker assisted selection techniques, the time drops to less than seven years.

"Applying molecular technologies to plant breeding increases efficiency," says Langridge.

Langridge says a good example is the nematode resistant strain of wheat being developed by the CRC. With traditional methods, the selection process would take place in potted plants and would require laborious measurement of the effects of nematode infections on each plant.

"Now we can use DNA analysis to determine susceptibility," said Langridge, explaining that this dramatically speeds things up.

Marker-assisted selection is currently one of the most powerful tools available to the plant biotechnologist. Knowing what gene or genes are important for the trait being developed means the breeder can easily select the plants carrying the right characteristics.

Marker identification programs are underway for all of the major crop and pasture varieties in Australia. CSIRO is looking at the five major crops - wheat and barley, rice, canola and cotton. The CRCMPB is also looking at wheat and barley, as well as pasture grasses like ryegrass. Others involved in marker identification research and marker-assisted breeding programs include CRCs and R&D Corporations for the different crop industries, such as the CRC for Sustainable Rice Production (the rice CRC) and the Grains Research and Development Corporation (GDRC).

Targets for gene discovery include disease resistance genes, genes for tolerance of herbicides or minerals such as boron, and stress tolerance genes. Genes for quality are also important, such as those which increase the nutritive value of the plant or plant product, or improve properties such as taste or appearance, or the activity of enzymes in the malting process.

Marker identification programs are not limited to crop research. Both the CRC for Viticulture (CRCV) and the CRC for Sustainable Production Forestry have research programs in gene discovery and genetic improvement.

Using gene discovery in agriculture Dr Liz Dennis, program leader in the Genomics and Plant Development program at CSIRO Plant Industry explained that there were several benefits to using plant genomics in agricultural biotech. First and foremost was using gene discovery methods to identify genes for use as markers in breeding programs. But genomics also provides a significant benefit to increasing the understanding of plant biology.

"It provides a basic understanding of how things work," she said, "by understanding what the genes are, for example, in aluminium tolerance, it helps understand the mechanism for the tolerance, and may assist in developing a strategy to deal with the problem."

"We have learnt a huge amount about the genetics of important traits," said Langridge, "We're finding out why there were some problems in the past."

He explained that some desirable traits are located very close to some not-so-desirable traits, making it difficult to select for one and not the other.

Plant genome projects are the hot topic at present. Arabidopsis is a small dicot plant that shares over 90 per cent similarity with canola, one of the most important crop plants. Dennis served as the chairperson of the international effort to obtain the sequence of the Arabidopsis genome. The sequence was obtained in late 2000.

Similar efforts, through several genome projects, have produced a genome sequence for rice, which is a monocot species. Japan has coordinated one large public project and both Monsanto and Syngenta, large multinational agribusinesses, have done sequences of their own. According to Dennis, a Chinese group has suddenly released a complete but un-annotated rice genome in the public domain.

Having these plant genomes, "makes a huge difference to gene discovery," said Dennis, explaining that the challenge now is to convert the new knowledge into useful crops, "bridging that gap between knowledge and agriculture."

The cost of genome sequencing Sequencing plant genomes is expensive. Dr Simon Robinson from the CRC for Viticulture (CRCV) estimated that obtaining the grapevine genome will cost at least $10 million and requires an international effort.

Beyond assisting plant breeding programs transgenic technologies help in the development of new varieties. This is the highly controversial subject of genetically modified organisms (GMOs). However, plant biotechnologists see the development of GM crop plants as being critical to agriculture in Australia and around the world.

The basis of transgenics, also known as genetic transformation, is adding a gene or genes to provide the plant with a characteristic that was not originally present. Examples of these characteristics include resistance to attack by insects or tolerance to herbicides used in weed control.

The first transgenic crop plant commercially available in Australia was Monsanto's INGARD Cotton, which contains an insecticidal gene from Bacillus thuringiensis or Bt. The Bt gene protects the cotton plant from attack by Heliothis pests, and Monsanto claims a 40 per cent reduction in the use of pesticides to protect the Bt cotton crops. At present, 30 per cent of Australia's annual cotton crop is allowed to be Bt cotton.

"The presence of transgenic cotton has enabled the industry to survive in Australia," said Dennis. She believes the industry faced a bleak future before the introduction of the transgenic insect-resistant variety.

Monsanto also has a herbicide-resistant cotton, known as Roundup Ready Cotton. A spokesperson for Monsanto said seeds are available that contain both traits. In addition, both Monsanto and Aventis CropScience are developing GM-Canola varieties with a number of different characteristics, including herbicide tolerance.

Other groups, including the CRCMPB, have transgenic plant projects. According to Langridge the most advanced area of these projects is pasture grasses with a range of characteristics including stress tolerance, disease resistance and quality. But, he said, "These are a long way from commercialisation."

In viticulture, the timelines are even longer. Robinson, program manager for the CRCV program for molecular improvement of grapevines, estimates that it takes at least 10 years to develop and evaluate transgenic grapevines. This means adoption of new technology by the viticulture industry will be slow. Attitudes in the industry toward GMOs will also hamper adoption time, he said.

"There is sensitivity in the wine industry about GMOs," said Robinson, adding that experimental GM grapevines are in many countries including France, Germany, USA and Australia.

Public concern One of the concerns about GMOs expressed by farmers and the general public is the possibility that the transgene might be transferred to other plants. Dr Chris Preston, a researcher at Adelaide University and a program leader with the CRC for Australian Weed Management, explained that while this can happen, the frequency is generally very low.

According to Preston, in a crop like canola, there is a certain level of outcrossing between the GM variety and non-GM varieties. Less frequent are pollinations between different species that are closely related. Pollination events between canola and wild radish, which is distantly related, would happen in 1 in 26 million pollinations. Between canola and other families of plants, pollination events never happen, he said.

In a field where wild radish and canola are both growing, hybrids can occur, but most of the hybrid seed is harvested along with the canola.

"For the most part, this is not a problem," said Preston, "it might become a minor management issue for the grower concerned."

The impact of plant genetics and biotechnology on the Australian economy is potentially huge. Agricultural crops in Australia are valuable, with wheat alone being worth around $5 billion per year.

"Relatively small gains in terms of improvement have a big benefit," said Langridge.

"Most of Australian agricultural produce is exported," said Dennis. She considers that it's crucial for organisations like CSIRO to maintain competition in the world scene.

"We are not a commercial organisation," she said, "CSIRO must have partners to take products to the farmers."

Increasingly, Australian State and Federal Governments are becoming players in agricultural biotechnology. Departments like the Primary Industries and Resources South Australia (PIRSA) and Victoria's department of Natural Resources and Environment (NRE) have active biotechnology programs and involvement in collaborative ventures like the CRC program.

"We think it is a very important role for the government to provide strategic R&D in priority areas," said Dr Bruce Kefford, executive director of Agriculture Victoria -- part of the Department of Natural Resources and Environment. He said the research at Agriculture Victoria's Plant Biotechnology Centre on dairy industry pasture crops and forage plants, such as ryegrass and white clover, is "the world's best."

Commercialisation Commercialisation of Australia's plant biotechnology industry is the next big step. With the rate of progress in discovering new genes and markers and development of breeding strategies, biotechnology companies focused on agriculture are starting to emerge.

"We recently launched AgGenomics, providing DNA fingerprinting for plant industries," said Prof German Spangenberg, Director of Agriculture Victoria's Plant Biotechnology Centre. The company was the result of a joint venture between Melbourne company Genetic Technologies and Agriculture Victoria Services, the commercial arm of Agriculture Victoria, he said.

Another biotechnology spin-off from the Plant Biotechnology Centre was Phytogene - the recipient of a BIF grant late last year. Pytogene was formed to commercialise a method for the manipulation of plant senescence technology.

"The plant industries increasingly depend on modern biotechnology," said Spangenberg, these platforms have to potential to provide quantum leaps in yield and quality of agricultural products.

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