Gene tech test for soil heath

Scientists at CSIRO are developing a method for using genetic technologies to determine the health of soil.

"We are developing molecular-based tools to study microbial drivers of chemical nutrient cycles in soils," said Dr Steve Rogers of CSIRO Land and Water, one of the two CSIRO divisions involved in the project. The second division is CSIRO Entomology.

"We don't look at the particular species or organisms that are responsible, we look at the functional genes involved," he explained. The project's initial focus is on genes involved in the nitrogen cycle, including ammonium oxidation and nitrogen fixation.

Rogers said that DNA and RNA were isolated straight from the soil and a number of techniques were then used to test for and quantify specific gene sequences. The expression of the genes was also examined by testing for mRNA.

"We are starting to look at functional gene sequence variation as well," Rogers said.

While the genes for vital processes such as nitrogen fixation are highly conserved across species, the researchers are able to analyse the variation in the sequences down to the base pair level, to assess the amount of genetic diversity in the microbial population of the soil.

"The higher the level of sequence diversity, the more resilient the soil," Rogers said.

The project was initially funded by the federal agency Land and Water Australia. Rogers said that a 12-month proof of concept study had recently been completed and that a three-year study at several sites around Australia was now in progress, again funded primarily by Land and Water Australia.

The team hopes to develop a technology platform for soil testing that would have wide commercial applications in the agricultural sector as well as for mine site rehabilitation and ecotoxicity testing.

Genes involved in other nutrient cycles like sulphur and phosphorous are also of interest to the team.

As the genes for processes like nitrogen fixation are ubiquitous, Rogers said that the technology would be applicable globally.

"People are used to these techniques in medical diagnosis," said Rogers. "This is the same approach applied to soils."