Characterisation of the complete chloroplast genome of the genus Lappula (Boraginaceae)
Annotatsiya
The evolutionary relationships and genomic variability within the genus Lappula Moench remain poorly understood due to limited genomic data and taxonomic complexity. In this study, we conducted a comparative analysis of the complete chloroplast genomes from eleven Lappula species to investigate plastome structure, sequence divergence, and phylogenetic relationships. All species exhibited the typical quadripartite structure of angiosperm plastome, with conserved gene content and order. Subtle but informative variations were detected at the inverted repeat boundaries, particularly involving the ndhF and ycf1 genes, reflecting lineage-specific expansion and contraction of inverted repeats. Nucleotide diversity analysis revealed several hypervariable regions, especially within intergenic spacers such as trnT-UGU-ndhJ and ycf4-cemA, which may serve as potential molecular markers for species delimitation. Phylogenomic reconstruction using complete plastome sequences resolved two major clades within Lappula and supported the relationships among the sampled species. These findings highlight the utility of whole plastome data for resolving interspecific relationships and underscore the need for expanded taxon sampling to refine the phylogeny and classification of Lappula within the tribe Rochelieae.