Unveiling the Genetic Diversity and Population Structure of the Endangered Fern Angiopteris fokiensis Through Genome Survey and Genomic SSR Markers

Angiopteris fokiensis is an endangered fern with ecological and medicinal value, yet genetic studies to support its conservation have been scarce. We performed a genome survey using high-throughput sequencing, developed genomic SSR markers from a draft assembly, and genotyped 96 individuals from 10 populations in Guangdong Province. The genome size was ~4.44 Gb (1.89% heterozygosity). From a 3.58 Gb contig assembly, 4,327,181 SSR loci were identified, with 15 highly polymorphic SSR markers being developed. Genotyping showed high within-population genetic diversity, low inter-population differentiation, and 98.55% of variation within populations. Bayesian structure, principal coordinates analysis, and neighbor-joining tree analyses consistently indicated admixed genetic clusters without clear geographical division. Additionally, the analysis revealed no significant correlation between genetic and geographic distances. Conservation should prioritize intra-population diversity via in situ/ex situ strategies. This study provides the first genomic SSR resources for A. fokiensis and underscores the importance of conserving within-population genetic diversity through integrated in situ and ex situ strategies.