The reference genome of Miscanthus floridulusilluminates the evolution of Saccharinae

Miscanthus, a member of the Saccharinae subtribe that includes sorghum and sugarcane, has been widely studied as a feedstock for cellulosic biofuel production. Here, we report the sequencing and assembly of the Miscanthus floridulusgenome by the integration of PacBio sequencing and Hi-C mapping, resulting in a chromosome-scale, high-quality reference genome of the genus Miscanthus. Comparisons among Saccharinae genomes suggest that Sorghumsplit first from the common ancestor of Saccharumand Miscanthus, which subsequently diverged from each other, with two successive whole-genome duplication events occurring independently in the Saccharumgenus and one whole-genome duplication occurring in the Miscanthusgenus. Fusion of two chromosomes occurred during rediploidization in M. floridulusand no significant subgenome dominance was observed. A survey of cellulose synthases (CesA) in M. floridulusrevealed quite high expression of most CesAgenes in growing stems, which is in agreement with the high cellulose content of this species. Resequencing and comparisons of 75 Miscanthusaccessions suggest that M. lutarioripariusis genetically close to M. sacchariflorusand that M. floridulusis more distantly related to other species and is more genetically diverse. This study provides a valuable genomic resource for molecular breeding and improvement of Miscanthusand Saccharinae crops.