Background: Paspalum notatum is a diploid multi-purpose subtropical herb native to South America. Its chromosome length is 2n=20XX and has a high ecological significance. It is currently widely planted in tropical and subtropical regions. Despite the gene pool of P. notatum being unearthed to a large extent in the past decade, no details about the genomic information of relevant species in Paspalum have been reported. In this study, the complete genome information of P. notatum was established and annotated through sequencing and de novo assembly of its genome.
Results: The latest PacBio third-generation HiFi assembly and sequencing revealed that the genome size of P. notatum is 541M. The assembly result is the highest index among the genomes of the gramineous family published so far, with a contig N50=52Mbp, scaffold N50=49Mbp, and BUSCOs=98.1%, accounting for 98.5% of the estimated genome. Genome annotation revealed 36511 high-confidence gene models, thus providing an important resource for future molecular breeding and evolutionary research. A comparison of the genome annotation results of P. notatum with other closely related species revealed that it had a close relationship with Zea mays. An analysis of the expansion and contraction of gene families suggested that P. notatum contains gene families associated with environmental resistance, increased reproductive ability, and molecular evolution, which explained its excellent agronomic traits.
Conclusion: This study is the first to report the high-quality chromosome-scale-based genome of P. notatum assembled using the latest PacBio third-generation HiFi sequencing reads. The study provides an excellent genetic resource bank for gramineous crops and invaluable perspectives regarding the evolution of gramineous plants. Keywords: Paspalum notatum ‘Flugge’, Genome, De novo assembly, Genome annotation