Source: CSIRO e-newsletter issue 12 summer 2005-2006

Scientists have planted a genetically modified (GM) rice trial at Wagga Wagga to identify useful genes for breeding improved conventional rice varieties.

Researchers at CSIRO Plant Industry, New South Wales Department of Primary Industries and Charles Sturt University hope to find rice genes that improve nutritional value or have agronomic value.

There are no plans to develop commercial GM rice varieties as a result of the trial.

The GM rice has been genetically modified by inserting a gene construct that switches off the rice gene it lands in.

In the field trial the team, led by CSIRO Plant Industry’s Dr Narayana Upadhyaya, will observe the GM rice plants to see if they are different.

If a seedling lacks vigour, for example, they will know that a gene involved in seedling vigour has been switched off. By tracking down the gene construct they can find the seedling vigour gene, which can then be used in conventional breeding.

The trial will also be used to investigate gene flow or cross pollination, if any, between GM rice and non-GM rice.

The trial has been approved by the Office of the Gene Technology Regulator and is fully enclosed and isolated from other rice plants.

This research is done as part of the NSW Agricultural Genomics Centre under the BioFirst Initiative of the NSW Government and has been supported by the Rural Industries Research and Development Corporation (RIRDC).

BACKGROUND

Application DIR 052/2004 for the GM rice trial was approved by the OGTR on 18 February 2005, see www.ogtr.gov.au/rtf/ir/dir052notific.rtf [RTF, 32kb].

The GM rice trial is Australia's part of an international effort to identify the function of each of the rice genes provided from the genome sequence.

Switching on or off the function of different genes helps to identify what trait those genes are responsible for. In particular CSIRO Plant Industry, NSW Department of Primary Industries and their collaborators in the NSW Agricultural Genomics Centre, are hoping to find genes that may improve nutritional value or have agronomic importance for the Australian rice industry, such as high vigour.

Understanding rice gene function and identifying useful rice genes could lead to the breeding of improved rice, including through conventional breeding.

There are no plans to develop commercial GM rice varieties as a result of this trial.

Within the trial scientists will also look at possible gene flow or cross pollination, if any, between GM rice and non-GM rice.

The GM rice

The GM rice that will be used in this trial has been genetically modified by randomly inserting a gene construct. The gene construct switches off the activity of the rice gene it 'lands' in.

For example the gene construct may land in the gene that is responsible for causing seedling vigour. If the gene lands in the seedling vigour gene it will switch it 'off' causing the seedling to lack vigour and as a result grow slowly and become stunted.

In the field trial the scientists will observe if the seedling lacks vigour and work backwards to find the easily recognisable gene construct and the seedling vigour gene it has landed in.

Using this process the scientists hope they will identify genes that may improve nutritional value or have agronomic importance, such as high vigour.

If the location of useful genes is known they can be 'flagged' and used in conventional breeding to determine if individual plants contain that particular gene and therefore the desired trait.

Herbicide and antibiotic resistance

The gene construct that has been inserted into the GM rice includes either herbicide resistance or antibiotic resistance. This is done to easily trace the gene construct.

The GM rice in this trial is not being grown for its herbicide or antibiotic resistance and there is no intention to breed herbicide or antibiotic resistant GM rice. The herbicide and antibiotic resistance traits are only used in the laboratory phase of the trial.

The herbicide and antibiotic resistance allows for those rice plants that have been successfully modified to be quickly and easily identified. If the rice is sprayed with herbicide (for example) the plants that survive are the ones that have the new gene construct.

The location

The trial is located at the Charles Sturt University campus in Wagga Wagga. The site is 85km from the nearest commercial rice crop and is also geographically isolated from naturalised wild rice populations and populations of native rice species.

The trial site will be 0.03 hectares, or 3 bays of 13 metres by 7.7 metres each. It is surrounded and completely enclosed overhead with a bird netting. It is also surrounded by a mice restrictive metal sheeting buried 50cm deep and protruding 50 centimetres which then attaches to the netting. The trial is further enclosed within a 2 metre boundary fence. The site will be closely monitored during and after the trial period.

GM rice seedlings have been raised in special water tubs at the site and were transplanted into two bays in November 2005. Conventional seed for the gene flow experiment has also been sown in one bay.

Cross pollination

Rice is a self pollinating plant, the pollen of which is short lived (5 minutes) and there are no known insect pollinators. It is therefore highly unlikely cross-pollination by wind with other rice plants outside of the trial area will occur.

Part of the trial will be used to determine if there is any gene flow, or cross pollination, between the GM rice and non-GM rice on the trial site.

This research is done as part of the NSW Agricultural Genomics Centre under the BioFirst Initiative of the NSW Government and has been supported by the Rural Industries Research and Development Corporation (RIRDC).