THE management of perennial ryegrass and its endophyte - which causes negative animal performance attributes such as ryegrass staggers - is a major breakthrough in the field of pasture genomics, according to AbacusBio's Kevin Smith.
Speaking at Dairy Innovation Day at Mount Gambier last week, he said some of the most exciting work he had been involved in was using genomic technology to better-develop certain strains of endophyte, a fungus that grew within the ryegrass plant.
"Endophytes cause negative animal performance attributes such as ryegrass staggers - caused by an alkaloid called lolitrem - and have positive effects such as reduction of insect feeding due to other compounds," he said.
"The way this association works is that different endophytes have the potential to produce different toxins. They interact with the grass, the animal and the environment, so it's a complex association."
Dr Smith said that using DNA fingerprinting to understand the genetic diversity of the endophyte and how it affected animal performance, research-ers were able to attribute the genetic variation to the compounds the endophytes produced.
He said a project, where a group of scientists collected endophytes from paddocks without a history of ryegrass staggers, found that all those endophytes had the potential to produce those toxic compounds.
"What we saw was that it was actually not the endophyte strain that was causing the more favourable performance in this particular case - it was either the environment or the way the plants were experiencing stresses," he said.
"This changed the way we were thinking about how to develop endophytes for Australia."
Using the same type of equipment used for sequencing human and cow genomes to sequence the endophyte genome, it was found that new strains of endophyte that were being developed or were soon to be released lacked the genes involved in lolitrem biosynthesis - the main compound that causes ryegrass staggers.
"We can be absolutely sure that when those strains are released, no matter what environment, no matter what genetic background, they will never produce lolitrem," he said.
"A number of breeding companies are now using this kind of technology to make sure what they're developing is more robust."
Steps towards DNA fingerprinting technology in pastures were being undertaken despite some geneticists considering it too hard a task. Animal breeding techniques had influenced how DNA fingerprinting could be used to maximum advantage.
*Full report in Stock Journal, June 09 issue, 2011.
