ABSTRACT: The complete assembly of vast and complex plant genomes, like the hexaploid wheat genome, remains challenging. Here, we present CS-IAAS, a comprehensive telomere-to-telomere (T2T) gap-free Triticum aestivum L. reference genome, encompassing 14.51 billion base pairs and featuring all 21 centromeres and 42 telomeres. Annotation revealed 90.8 Mb additional centromeric satellite arrays and 5,611 ribosomal DNA(rDNA) units. Genome-wide rearrangements, centromeric elements, TE expansion, and segmental duplications were deciphered during tetraploidization and hexaploidization, providing a comprehensive understanding of wheat subgenome evolution. Among them, TE insertions during hexaploidization greatly influenced gene expression balances, thus increasing the genome plasticity of transcriptional levels. Additionally, we generated 163,329 full-length cDNA sequences and proteomic data that helped annotate 141,035 high-confidence (HC) protein-coding genes. However, in such a hexaploidy genome, 20.05%, 33.43%, and 42.76% of gene transcript levels, alternative splicing events, and protein levels were detected unbalancing among subgenomes. The complete T2T reference genome (CS-IAAS), along with its transcriptome and proteome, represents a significant step in our understanding of wheat genome complexity, and provides insights for future wheat research and breeding.
guochen qin 
