Chromosome-level genome assembly of Pteroceltis tatarinowii provides new insights into evolution and fiber biosynthesis

Pteroceltis tatarinowii, a unique single-species plant and fibrous tree in China, is the raw material for making Xuan paper. However, the lack of a complete genome sequence has limited both basic and applied research on P. tatarinowii. We describe two high-quality chromosome-level haplotype genomes with lengths of 366.41 Mb and 362.96 Mb, with 38,502 and 43,005 predicted genes, respectively. Genome analyses supported the classification of P. tatarinowii into the Cannabaceae family and suggested that it experienced only 1 WGD event. The genes involved in cellulose and lignin synthesis expanded significantly in the genome, which reflected the fiber properties of P. tatarinowii. The cellulose and lignin metabolic pathways identified via transcriptome showed that the CELB, BGLU and GYS genes may play key roles in cellulose synthesis and that the Prx and UGT72E genes may play key roles in lignin synthesis. Further transgenic verification revealed that the CELB-1 gene negatively regulates cellulose synthesis, the CELB-2 gene positively regulates cellulose synthesis, and the Prx-1 and Prx-2 genes positively regulate lignin synthesis. This work provides biological evidence for the classification and evolution of P. tatarinowii, and provides a cornerstone for understanding the underlying genetics regulating the synthesis of fibers in P. tatarinowii.