Genomic assessment of Torenia concolor (Linderniaceae) highlights unique conservation value of regionally rare populations

Biodiversity status assessments are typically conducted on a regional basis. Consequently, there are numerous species that are rare in one region but ubiquitously present in another country or administrative region. Correctly assessing the conservation status and conservation value of such "endangered species" is essential to achieve better biodiversity conservation through the appropriate and efficient use of socioeconomic resources. A comparative genomic analysis was conducted on Torenia concolor (Linderniaceae), which is widely distributed in Southeast and East Asia, but has a limited population in Japan, specifically on Amami-Oshima Island. This population has not yet been definitively established as a conservation priority due to the possibility that it may have originated from cultivated plants. Our findings indicate that the Amami-Oshima population is derived from a natural distribution and is phylogenetically unique, retaining comparable genetic diversity with more abundant populations and exhibiting no increase in deleterious variations in their genome. These results suggest that the Amami-Oshima population has its own unique conservation value and that relatively simple conservation measures can be implemented to ensure its sustainability, given its genomic health. This study highlights the importance of accurate assessment of genomic status and contributes to a broader understanding of conservation strategies for regionally rare species.