Ah-reum Go1P, Ki-Oug Yoo1

1Department of Biological Sciences, Kangwon National University, Chuncheon, Korea

In this study, we report complete chloroplast genomes of three species within Viola subsect. Rostratae (V. faurieana, V. jordanii, and V. rostrata) and perform comparative plastome analyses of 11 taxa to reassess phylogenetic relationships and series-level classification. The three species possessed chloroplast genomes of 158,179 to 158,489 bp in length, each comprising 84 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. IRscope analysis revealed ΨndhF formation in V. jordanii at the IR-SSC boundary. mVISTA analysis showed nucleotide variation was concentrated in non-coding regions of the LSC and SSC, with East Asian ser. Rosulantes exhibiting similar variation patterns. Phylogenetic analysis strongly supported the monophyly of subsect. Rostratae (BP=100, PP=1.00). At the series-level, European ser. Arosulatae taxa occupied the basal position, distinct from East Asian taxa. Sers. Rosulantes and Mirabiles formed a well-supported clade, within which East Asian ser. Rosulantes taxa formed a distinct subclade. Comprehensive subsect. Rostratae studies were previously lacking, preventing biogeographic patterns from series classification. This study demonstrates that geographic divergence constitutes a significant series-level character, requiring systematic revision. Future studies will integrate nuclear DNA data, morphological data, and time-calibrated phylogenetic analysis to resolve divergence times and historical biogeography within subsect. Rostratae.