Rheum officinale,a member of the Polygonaceae family,is an important medicinal plant that is widely used in traditional Chinese medicine.Here,we report a 7.68-Gb chromosome-scale assembly of R.officinale with a contig...Rheum officinale,a member of the Polygonaceae family,is an important medicinal plant that is widely used in traditional Chinese medicine.Here,we report a 7.68-Gb chromosome-scale assembly of R.officinale with a contig N50 of 3.47 Mb,which was clustered into 44 chromosomes across four homologous groups.Comparative genomics analysis revealed that transposable elements have made a significant contribution to its genome evolution,gene copy number variation,and gene regulation and expression,particularly of genes involved in metabolite biosynthesis,stress resistance,and root development.We placed the recent autotetraploidization of R.officinale at~0.58 mya and analyzed the genomic features of its homol-ogous chromosomes.Although no dominant monoploid genomes were observed at the overall expression level,numerous allele-differentially-expressed genes were identified,mainly with different transposable element insertions in their regulatory regions,suggesting that they functionally diverged after polyploidization.Combining genomics,transcriptomics,and metabolomics,we explored the contributions of gene family amplification and tetraploidization to the abundant anthraquinone production of R.officinale,as well as gene expression patterns and differences in anthraquinone content among tissues.Our report of-fers unprecedented genomic resources for fundamental research on the autopolyploid herb R.officinale and guidance for polyploid breeding of herbs.展开更多
基金supported by the Natural Science Foundation of Hebei Province (grant C2021201048)the National Natural Science Foundation of China (grant 32100500)the Young Elite Scientists Sponsorship Program by CAST grant YESS20210080.
文摘Rheum officinale,a member of the Polygonaceae family,is an important medicinal plant that is widely used in traditional Chinese medicine.Here,we report a 7.68-Gb chromosome-scale assembly of R.officinale with a contig N50 of 3.47 Mb,which was clustered into 44 chromosomes across four homologous groups.Comparative genomics analysis revealed that transposable elements have made a significant contribution to its genome evolution,gene copy number variation,and gene regulation and expression,particularly of genes involved in metabolite biosynthesis,stress resistance,and root development.We placed the recent autotetraploidization of R.officinale at~0.58 mya and analyzed the genomic features of its homol-ogous chromosomes.Although no dominant monoploid genomes were observed at the overall expression level,numerous allele-differentially-expressed genes were identified,mainly with different transposable element insertions in their regulatory regions,suggesting that they functionally diverged after polyploidization.Combining genomics,transcriptomics,and metabolomics,we explored the contributions of gene family amplification and tetraploidization to the abundant anthraquinone production of R.officinale,as well as gene expression patterns and differences in anthraquinone content among tissues.Our report of-fers unprecedented genomic resources for fundamental research on the autopolyploid herb R.officinale and guidance for polyploid breeding of herbs.
