Sequencing and Analysis of the Eucalyptus grandis Genome

The annotated draft genome sequence of Eucalyptus grandis, a globally important forestry species representing the Rosid order Myrtales, was released by the DOE-JGI in 2011 (http://www.phytozome.net/eucalyptus.php). The draft genome assembly (7.7 million Sanger reads, 8X coverage) comprises 605 Mbp in 11 mapped chromosome scaffolds and 85 Mbp in 4941 smaller, unlinked scaffolds (N/L50: 5/53.9 MB). Ab initio and homology-based gene prediction, supported by over 4 million EST reads allowed annotation teams at JGI and University of Ghent to identify 44,974 and 47,974 protein coding loci, respectively. Preliminary analyses suggest that the Eucalyptus genome has undergone at least one recent genome-wide duplication, in addition to the ancient hexaploidization event shared by Rosids and Asterids. Tandem duplication of gene loci is prevalent in the E. grandis genome and has resulted in the expansion of clades of key gene families including families involved in wood formation and secondary metabolism. The E. grandis genome (640 Mbp) has also undergone expansion relative to that of other eucalypts (e.g. E. globulus, 530 Mbp), which could be related to a recent burst of transposable element activity in E. grandis.  Ongoing efforts by members of the Eucalyptus Genome Network (EUCAGEN) aim to annotate the predicted proteome as well as key gene families involved in biotic and abiotic stress tolerance, wood formation, flowering and secondary metabolism (www.eucagen.org). The genome sequence of Eucalyptus offers exciting new opportunities to unravel the unique biology of large woody perennials and develop powerful genomic tools for tree improvement.