New Zealand genome work holds key to grassland restoration

A New Zealand scientist who sequenced the genome of a rare bacterium from the soils of the American prairielands said Tuesday the work could help restore other at-risk ecosystems.

Auckland University biology researcher Kim Handley was part of an international team studying microbial diversity in the remaining prairie lands of the United States Midwest.

The team had been working to reconstruct the microbial content of prairie soils as part of restoration efforts, and mapping soil microbial communities was likely to help improve the long-term success of these conservation efforts, Handley said in a statement.

The team painstakingly investigated original prairie soils from Colorado and discovered a poorly-studied bacterium known as Verrucomicrobia was one of the most abundant microbes.

But detailed analysis of Verrucomicrobia proved difficult because it had never been reproduced in culture in a lab, so Handley sequenced the genome direct from a soil sample using a method known as shotgun metagenomics.

The method involved extracting organic material from soil such as roots and seeds and chopping it into small DNA fragments, before sorting individual genome sequences.

"The bacterium has a highly streamlined genome compared with its nearest neighbours, suggesting an extremely efficient mode of life not previously recognized in soil bacteria," Handley said.

The prairies once covered more than 65 million hectares of the Midwest, supporting huge herds of bison, but the spread of agriculture from the mid-19th century has left only small patches of tallgrass prairie.

Handley said the reconstruction of the microbial makeup of prairie soils would ensure that restoration efforts were guided by soil science.

"This work demonstrates that we can use advances in science such as DNA sequencing to quantify how historical changes have altered the diversity and function in a whole range of soil ecosystems over time," said Handley. Endit