Complete telomere-to-telomere assemblies of two sorghum genomes to guide biological discovery

Sorghum is a C4 crop well-known for its high efficiency of biomass accumulation and adaptation to drought and hot environments. This study reports the assembly of complete genome sequence of two sorghum genomes using a combination of ultra-long reads from Oxford Nanopore Technology, high-fidelity long reads from Pacbio and Hi-C reads. The accuracy and completeness of the T2T assemblies were comprehensively validated using a range of parameters, including coverage depth assessment, BUSCO, LTR assembly index, ect. Our T2T assembly of BTx623 identified 36.25 Mb of new sequence, in addition to dozens of misoritation and mispositioning of large DNA segments in the BTx623-v3. Correcting these assembly errors in the reference genome is critical for exploiting genetic information in these complex regions in sorghum. Comparison of the two T2T genomes shed new insights on variation of centromeres in sorghum. The two high-quality T2T genomes represent an important resource for sorghum improvement and gene discovery. They would serve as the new reference genomes to unlock the full potential of global sequence variation of this valuable crop.