Chromosome-level genome assembly of Iodes seguinii and its metabonomic implications for rheumatoid arthritis...

Iodes seguinii is a woody vine known for its potential therapeutic applications in treating rheumatoid arthritis (RA) due to its rich bioactive components. Here, we achieved the first chromosome-level assembly of the nuclear genome of I. seguinii using PacBio HiFi and chromatin conformation capture (Hi-C) sequencing data. The initial assembly with PacBio data produced contigs with an N50 length of 9.71 Mb, and Hi-C data anchored these contigs into 13 chromosomes, achieving a total length of 273.58 Mb, closely matching the estimated genome size. Quality assessments, including BUSCO, long terminal repeat assembly index, transcriptome mapping rates, and sequencing coverage, confirmed the high quality, completeness, and continuity of the assembly, identifying 115.28 Mb of repetitive sequences, 1062 RNA genes, and 25,270 protein-coding genes. Additionally, we assembled and annotated the 150,599 bp chloroplast genome using Illumina sequencing data, containing 121 genes including key DNA barcodes, with maturase K (matK) proving effective for species identification. Phylogenetic analysis positioned I. seguinii at the base of the Lamiales clade, identifying significant gene family expansions and contractions, particularly related to secondary metabolite synthesis and DNA damage repair. Metabolite analysis identified 84 active components in I. seguinii, including the discovery of luteolin, with 119 targets predicted for RA treatment, including core targets like AKT1, toll-like receptor 4 (TLR4), epidermal growth factor receptor (EGFR), tumor necrosis factor (TNF), TP53, NFKB1, janus kinase 2 (JAK2), BCL2, mitogen-activated protein kinase 1 (MAPK1), and spleen-associated tyrosine kinase (SYK). Key active components such as flavonoids and polyphenols with anti-inflammatory activities were highlighted. The discovery of luteolin, in particular, underscores its potential therapeutic role. These findings provide a valuable genomic resource and a scientific basis for the development and application of I. seguinii, addressing the genomic gap in the genus Iodes and the order Icacinales and underscoring the need for further research in genomics, transcriptomics, and metabolomics to fully explore its potential.