Australian tree genome sequenced in part at HudsonAlpha

Second species of eucalypt sequenced in a decade-long project that spanned three continents

Scientists at the HudsonAlpha Genome Sequencing Center contributed their expertise to the development of yet another high-quality plant genome. The international team, which included scientists in Australia, Brazil and the United States, published the new reference genome for a woody plant called Corymbia citriodora in Communications Biology earlier this month.

Corymbia citriodora is a member of the Myrtaceae family which includes many species of hardwood trees. It is native to Australia but is grown for timber, pulp and paper, and essential oils in Australia, South Africa, Asia, and Brazil. Corymbia can maintain a high-growth rate under less-than-ideal conditions brought on by drought, poor-quality soil, and biotic stresses caused by viruses, bacteria, fungi, nematodes, insects, arachnids and weeds.

Scientists in Australia at the University of Queensland, Southern Cross University, University of the Sunshine Coast, and University of Tasmania set out to sequence the genome of Corymbia citriodora to better understand the genetic basis of its desirable traits in order to improve breeding programs and create hardier trees.

So just how did the genome of an Australian tree end up all the way in Huntsville, Alabama at the HudsonAlpha Genome Sequencing Center? Sequencing the genome was part of a Joint BioEnergy Institute (JBEI) project in collaboration with the US Department of Energy Joint Genome Institute. Lead scientist Adam Healey, PhD, visited the HudsonAlpha Institute for Biotechnology in Huntsville, Alabama, to get help with refining the genome. He later returned to the Institute after completing his PhD at the University of Queensland and began his role as a computational biologist in the Genome Sequencing Center.

“While working on my doctorate in Australia, I was introduced to Jeremy Schmutz (co-director of the GSC) and Jerry Jenkins (Genome Analysis Group Leader at the GSC) through this project,” says Healey. “This project precipitated my move to HudsonAlpha. When offered the opportunity to move to the States and join the team of world leaders in plant genomic science, I jumped at the chance.”

The research team sequenced and assembled the 408 Mb genome of Corymbia citriodora and compared it against other members of the Myrtaceae family to identify unique genes or genetic changes. They discovered that Corymbia citriodora has undergone functional enrichments for genes involved in pathogen inhibition, heat tolerance, and desiccation resistance, as well as pollinator attraction and wax and terpene biosynthesis. These changes enable Corymbia citriodora’s successful adaptation to the different stresses and environmental conditions of the Australian continent.

The new Corymbia citriodora genome will serve as the reference genome for the genus Corymbia. The reference genome is a valuable resource for future gene discovery and will help the breeding of hardwood eucalypts for uses including timber and biomass production, carbon sequestration and even essential oil and charcoal production.