Comparative Genomic Analysis of Wild Cymbidium Species from Fujian Using Whole-Genome Resequencing

In this study, we performed whole-genome resequencing (WGS) to investigate genomic variation and functional divergence among four wild Cymbidium species—C. ensifolium, C. sinense, C. kanran, and C. floribundum—collected from Fujian Province, China. A total of 350.58 Gbp of high-quality sequencing data was obtained from 13 samples, enabling comprehensive identification of SNPs and InDels. Genomic variants were unevenly distributed, with lower variation in gene-rich regions and higher levels in non-coding areas. Circos plots and variant density heatmaps revealed significant regional differences across chromosomes, with longer chromosomes exhibiting greater variant enrichment in 1 Mb windows. C. floribundum harbored the highest number of nonsynonymous SNPs and InDel-associated genes, whereas C. sinense and C. kanran had fewer mutations. KEGG pathway enrichment analysis revealed species-specific functional divergence, particularly in metabolism, stress response, and secondary metabolite biosynthesis. Population structure analysis and principal component analysis (PCA) indicated genetic differentiation among these species Notably, C. kanran exhibited high within-population genetic diversity. These findings provide essential genomic resources for the conservation and functional studies of wild Cymbidium species in subtropical China.