Prospects: The Spruce Genome, a Model for Understanding Gymnosperm Evolution and Supporting Tree Improvement Efforts

The spruce reference genomes (Picea abies, P. glauca, P. glauca x engelmannii) were published eight years after the release of Populus trichocarpa’s genome, the first forest tree species ever sequenced (Science 313:1596–1604 (2006)). Although sequencing these highly complex 20 Gigabases spruce genomes represented a major achievement, the current assemblies present many limitations and a chromosome-level assembly reference in this ecologically and economically important genus is still far from reach (Chaps. 2, 7, 8). Nevertheless, improvements in next-generation sequencing technologies and bioinformatic methods have led to important advancements as outlined in this book (Chap. 3). Increasingly complete and more accurate spruce genome sequences will serve the research community in many aspects. Foremost, they will enable improved annotations in the gene space, new discoveries in plant secondary metabolism, and support new breeding strategies for physiologically active compounds and beyond (Chaps. 5, 9, 12, and 13). An even more uncharted territory is the elucidation of epigenetic memory (Chaps. 4 and 6). In the context of adaptation to future climates, spruces are prime study subjects, as important representatives of boreal ecosystems (Chaps. 10 and 11). Following the example of plant species with less complex genomes, whole-genome resequencing will become state-of-the-art in population genomics of spruces and thus invaluable for finding the most important genetic/genomic variants underlying traits of interest. This volume details the progress of the spruce genome sequencing efforts as a cornerstone for exciting discoveries in gymnosperm genomics.