Ag genomics centre heralds toxicity discoveries

Two years after it was established, the NSW Agricultural Genomics Centre is showing its mettle, announcing the discovery of several DNA markers for genes conferring tolerance to aluminium toxicity.

The centre is a partnership involving the NSW Department of Primary Industries, CSIRO Plant Industry, CSIRO Mathematical and Information Sciences, and the Autralian Proteome Analysis Facility (APAF) in Sydney.

The centre’s director, Dr Liz Dennis, of CSIRO Plant Industry, said the new markers, identified by NSW Primary Industries wheat breeders at Wagga, will help cereal breeders to accelerate breeding programs to develop aluminium tolerant wheat varieties that will yield well in the extensive tracts of acid soils throughout Australia’s temperate agricultural zone.

Dennis said aluminium toxicity in acid-soil regions caused up to $1 billion in lost agricultural production annually. Acid soils rank with salinity as an environmental problem in south-eastern Australia’s higher rainfall zone. Most of the soils are naturally acid, but a slow accumulation of nitric acid during decades of growing subterranean clover pastures has driven acidity levels below pH 5 on many grazing properties.

As well as reducing productivity, acidity erodes the land’s capital value, limiting farmer’s ability to restore the land by liming affected soils. Aluminium tolerant wheats or other crops would generate the cash flow farmers need to to take remedial action.

The aluminium tolerance genes encode aluminium transport proteins that operate in root cels, accumulate and rejecting aluminium ions.

The centre has also identified other genes in rice, wheat and cotton, including genes involved in cotton fibre development. Researchers have developed DNA microarrays to explore the activity of gene networks in wheat and cotton.

Dennis said researchers have used 'knockout' mutations to identify five mutations that block lint production in cotton. These genes will provide entry points to explore the pathways involved in lint production.

Geneticists are using DNA markers to track and identify genes that influence dough extensibility in bread wheat, while APAF researchers are using proteomics technology to identify the proteins associated with the markers -- which in turn allows geneticists to identify the genes with DNA probes derived from the protein sequences.

The centre is also involved in the international Rice Gene Machine project, which aims to determine the function of all the genes identified in the rice genome project.

Acid-tolerant eucalypt developed

Meanwhile, Japanese researchers have developed a genetically modified eucalypt that can tolerate acid soils, and plan to use it as a rootstock to take grafts of other eucalypts developed for pulp and paper production.

The Oji Paper Company has already conducted successful grafting experiments, according to an article in the Nikkei Report, and plans to exploit the acid-tolerant rootstock to establish eucalypt plantations on acid soils in tropical nations like Vietnam.

Oji Paper said it is conducting greenhouse experiments to confirm that there is no risk of transgenes in the GM eucalpt understock escaping to contaminate the environment.

The Nikkei Report said one third of the world’s soils are too acid for plantation eucalypts, including areas where the climate is otherwise ideal for eucalypts.