The Chromosome-based Genome of <i>Paspalum vaginatum</i> Provides New Insights into Salt-stress Adaptation

Abstract Salinization is increasingly a major factor limiting production worldwide. Revealing the mechanism of salt tolerance could help to create salt-tolerant crops and improve their yields. We reported a chromosome-scale genome sequence of the halophyte turfgrass Paspalum vaginatum , and provided structural evidence that it shared a common ancestor with Z. mays and S. bicolor . A total of 107 P. vaginatum germplasms were divided into two groups (China and foreign group) based on the re-sequenced data, and the grouping findings were consistent with the geographical origin. Genome-wide association study (GWAS) of visually scored wilting degree and withering rates identified highly significant QTL on chromosome 6. Combination with RNA-seq, we identified a significantly up-regulated gene under salt stress, which encodes ‘High-affinity K + Transporter 7’ ( PvHKT7 ), as strong candidates underlying the QTL. Overexpression of this gene in Arabidopsis thaliana significantly enhanced salt tolerance by increasing K + absorption. This study adds new insights into salt-stress adaptation of P. vaginatum and serve as a resource for salt-tolerant improvement of grain crops.