12 June 2014
Scientists have sequenced the genetic code of the eucalypt for the first time, providing fresh insights into the Australian icon that has become the world’s favourite hardwood.
Australian researchers from the University of Tasmania, The University of Melbourne, the Victorian Department of Environment and Primary Industries, the Australian National University, Western Australian Department of Parks and Wildlife and the University of the Sunshine Coast collaborated with 30 institutions in nine countries to sequence and analyse the genome of the Flooded Gum (Eucalyptus grandis).
“Efforts to sequence the genome of a eucalypt started over a decade ago,” explained USC’s Dr Dorothy Steane, who was a co-author of the paper that was published online today in the international scientific journal Nature.
“The idea was originally discussed at the inaugural meeting of the International Eucalypt Genome Network, held in Hobart in 2004,” Dr Steane said.
“Since then, there have been a number of international workshops, meetings and other exchanges that have brought the international eucalypt research community together to discuss, and now create, the resources to unlock the potential of eucalypts as a truly global fuel and fibre source.”
Native to Australia, Eucalyptus trees have become the world’s most widely planted hardwood due to their fast growth, adaptability and complex oils.
Dr Antanas Spokevicius of the University of Melbourne said eucalypts were now the hardwood plantation species of choice in many parts of the world for applications like paper-making and bio-energy.
“This resource will provide a huge boost for breeding and biotechnological tree improvement programs and has put eucalypts on the same footing as many other important crop species, whose improvement programs have benefited greatly from a sequenced genome,” Dr Spokevicius said.
Dr Steane, a Collaborative Research Networks (CRN) Research Fellow at USC, said there were more than 700 species of Eucalyptus growing across a wide range of environments, from wet tropics to alpine shrublands and to the arid interior.
“The genome sequence of flooded gum provides us with the means to investigate the essential differences between species and to understand how eucalypts have adapted to so many different environments,” she said.
“It gives us resources to help us develop drought-resilient plantations for future generations.” Dr Carsten Kulheim of Australian National University agreed: “The genetic code will help us understand a foundation species of many Australian eco-systems and how these affect other species, from fungi and insects through to marsupials”.
The researchers identified 113 genes responsible for synthesising terpenes, the familiar aromatic essential oils of eucalypts. These oils provide chemical defence against pests as well as the familiar aromatic essential oils used in both medicinal cough drops and for industrial processes.
They may be extremely important in understanding feeding preferences of animals such as the endangered koala, while genome-based research could also one day lead to eucalypt oils being used as a base for jet fuel.
Dr Steane said the genome sequence consisted of 640 million base pairs of DNA, containing over 36,000 genes – almost twice the number of genes in the human genome.
The detailed analysis of the Eucalyptus genome revealed an ancient whole-genome duplication event estimated to have occurred about 110 million years ago, almost twice as long ago as the extinction of the dinosaurs.
“Duplication of genes may be one of the reasons that eucalypts have been able to adapt to so many diverse environments across Australia,” Dr Steane said.
— Terry Walsh