Abstract - Eucalyptus trees are widespread across Australia, providing habitat to a rich biodiversity of marsupials, birds and insects, being key foundation species in natural ecosystems. Using long-read sequencing, we investigated how Eucalyptus genome architecture has changed over time to unveil their adaption to the environment. We investigated a key species, E. viminalis, which is experiencing high mortality and dieback in NSW. Long-read sequencing of 50 wild E. viminalis trees across three populations identified thousands of genome structural variations (SVs) segregating within the populations, potentially influencing adaptation. These SVs had influenced genes in multiple ways, including deleting gene exons, disrupting gene order, translocation of genes, and complete deletion of genes. This included phenotypically important genes such as the terpene synthase gene family. We further extended this work by assembling the genomes of 33 diverse Eucalyptus species, which span millions of years of evolution. We observed a dramatic increase in genome SVs as species diverged, suggesting these play a key role in early architectural divergence. Further divergence led to mutations obscuring rearrangements and a loss of syntenic regions (gene order conservation). Insertions, deletions, duplications, inversions and translocations were observed as major contributors to genome structural divergence. Our pioneering research on SVs in Eucalyptus provides insights into understanding their role in genome evolution and adaptive traits for this ecologically important genus.

Biography - Ash is a postdoctoral fellow at the Australian National University conducting genome research on a wide variety of Australian native plants, and invasive fungi that threaten plant biodiversity. He has been developing innovative approaches to apply Oxford Nanopore sequencing to drive scientific breakthroughs in genome evolution of trees and understanding plant-pathogen interactions. His current research investigates genome structural rearrangements within Eucalyptus trees to unveil critical insights into adaptive traits, novel phenotypes, and evolutionary mechanisms. Ash’s innovative nature and expertise has garnered him the nickname "DNA Whisperer", and he continues to push the boundaries of plant and fungal genomics.