Desiccation Tolerance Evolved through Gene Duplication and Network Rewiring in .

Although several resurrection plant genomes have been sequenced, the lack of suitable dehydration-sensitive outgroups has limited genomic insights into the origin of desiccation tolerance. Here, we utilized a comparative system of closely related desiccation-tolerant () and -sensitive () species to identify gene- and pathway-level changes associated with the evolution of desiccation tolerance. The two high-quality genomes we assembled are largely collinear, and over 90% of genes are conserved. and have evidence of an ancient, shared whole-genome duplication event, and retained genes have neofunctionalized, with desiccation-specific expression in Tandem gene duplicates also are enriched in desiccation-associated functions, including a dramatic expansion of early light-induced proteins from 4 to 26 copies in A comparative differential gene coexpression analysis between and supports extensive network rewiring across early dehydration, desiccation, and rehydration time courses. Many genes show significantly higher expression in compared with their orthologs in Coexpression modules uniquely upregulated during desiccation in are enriched with seed-specific and abscisic acid-associated -regulatory elements. These modules contain a wide array of seed-associated genes that have no expression in the desiccation-sensitive Together, these findings suggest that desiccation tolerance evolved through a combination of gene duplications and network-level rewiring of existing seed desiccation pathways.