CSIRO applies for GM rice field trial

CSIRO Plant Industry has applied to the Office of the Gene Technology Regulator (OGTR) to conduct a field trial of gene-knockout rice varieties, as part of the national research organisation's contribution to the international 'Green Machine' functional genomics project.

The single-gene knockout rice varieties, created with CSIRO's patented Hellsgate RNA-interference (RNAi) vectors, have been developed to identify genes that could be targeted by conventional breeding programs - or re-engineered with recombinant DNA technology - to improve the agronomic performance and nutritional properties of rice.

Plant Industry Assistant Chief Dr TJ Higgins said the division's researchers had created thousands of knockout lines. CSIRO has applied to test them under field conditions in Wagga, which is sufficiently distant from the commercial rice farms of the Riverina region to negate any risk of cross-pollination.

"The sort of things we are interested in are genes that may influence early vigour, so rice seedlings can out-compete weeds, frost tolerance, salt tolerance, and protein content," Higgins said.

He said frost-tolerance was a "huge" objective for rice breeders - in most regions of the world, rice is grown in flooded paddy fields to insulate the plant's flowers against injury by frosts.

If more frost-tolerant strains could be developed, Higgins said they would allow the rice-growing season to be extended in temperate regions of Australia where it was currently limited by low temperatures. Frost-tolerant cultivars would give growers greater flexibility in scheduling harvest times to take advantage of seasonal and market conditions.

He said rice breeders were also keen to improve the protein content of rice, which, at a mere 7 per cent, little more than half that of wheat. High-protein rice would increase the nutritive value of rice for people in chronically protein-deficient developing nations.

The emphasis would be on using DNA markers to identify and hybridise high-protein lines to produce high-protein varieties. Rather than outsource genes from other species, the emphasis would be on lifting protein content by identifying high-expressing variants of existing genes in rice.

"We aim to find lines that have more of their carbon production allocated to protein, which means we would have to get the nitrogen levels in the soil right," Higgins said.