Chromosome-level genome assembly of a thick-walled variety of moso bamboo

Moso bamboo (Phyllostachys edulis), which is valued for both its edible shoots and versatile timber, has long been recognized as a prominent species of bamboo owing to its rapid growth and favorable properties. P. edulis var. `Pachyloen` is a variety of moso bamboo, which is well-known for its thicker culm. However, a lack of information on information about its genome has led to slow progress in studies of the mechanism of culm thickening in this variety. This study presented a high-quality genome assembly of 1.96 Gb for this thick-walled variety of moso bamboo, P. edulis var. `Pachyloen`, using both single-molecule sequencing from the Pacific Biosciences (PacBio) Sequel platform and chromosome conformation capture sequencing (Hi-C). There were approximately 71.65% repetitive sequences in the genome of this variety, and 38,993 protein-coding genes were annotated based on transcriptomes from eight stages of belowground shoots. Comparative genomics were used to show that this variety had 2974 expanded gene families and 2143 contracted gene families. Plus, it had experienced two whole genomic duplication events in ancient and recent times. Transcriptome sequencing using RNA-Seq identified the key genes involved in the lignin and cellulose biosynthetic pathways in the thick-walled moso and revealed the central role of auxin in the biosynthesis of cell walls as the culms thickened. The genomic resources and candidate genes presented here will serve as a solid foundation for future studies on its biosynthesis and support the use of P. edulis var. `Pachyloen' as a valuable model to investigate the development of culms in plants, particularly species of bamboo.