Within the complicated and controversial taxonomy of cosmopolitan genus Salvia L. (Lamiaceae) are valuable species Salvia officinalis L. and Salvia sclarea L., which are important for the pharmaceutical, ornamental horticulture, food, and perfume industries. Genome organization and chromosome structure of these essential oil species remain insufficiently studied. For the first time, the comparative repeatome analysis of S. officinalis and S. sclarea was performed using the obtained NGS data, RepeatExplorer/TAREAN pipelines and FISH-based chromosome mapping of the revealed satellite DNA families (satDNAs). In repeatomes of these species, LTR retrotransposons made up the majority of their repetitive DNA. Interspecific variations in genome abundance of Class I and Class II transposable elements, ribosomal DNA, and satellite DNA were revealed. Four (S. sclarea) and twelve (S. officinalis) putative satDNAs were identified. Based on patterns of chromosomal distribution of 45S rDNA; 5S rDNA and the revealed satDNAs, karyograms of S. officinalis and S. sclarea were constructed. Promising satDNAs which can be further used as chromosome markers to assess inter- and intraspecific chromosome variability in Salvia karyotypes were determined. The specific localization of homologous satDNA and 45S rDNA on chromosomes of the studied Salvia species confirmed their common origin, which is consistent with previously reported molecular phylogenetic data.

The genus Salvia L. (Lamiaceae) is characterized by complex taxonomy and controversial phylogeny. This genus includes about a thousand species with worldwide distribution and high ecological, structural, functional and morphological diversity. Because of their high content of essential oils, various Salvia plants are widely used in medicine, as well as in the food, perfume, cosmetic, and paint industries; they also are valuable melliferous resources. The present study reviews the taxonomic history of the genus Salvia and the phylogenetic relationships between the taxa within the subgenera Salvia, Sclarea, and Glutinaria. Among the Salvia species, three basic chromosome numbers, x = 7, x = 8, and x = 11, were most common, although other basic chromosome numbers (x = 6–19) were determined, which was probably due to events of dysploidy, aneupoidy, and/or polyploidy occurring during speciation. Recent molecular cytogenetic studies based on Next Generation Sequencing technologies have clarified the chromosomal organization of several Salvia species. The patterns of chromosome distribution of 45S rDNA, 5S rDNA, and satellite DNAs made it possible to assess their intra- and interspecific chromosome diversity. However, further cytogenetic studies are needed to characterize the chromosomes in the genomes of other Salvia species and specify the genomic relationships among them.

Polemonium caeruleum L. (Polemoniaceae) is a perennial flowering plant native to Eurasia and North America, which is used as a fodder, medicinal, and ornamental plant. Many issues related to the taxonomy and origin of this valuable species still remain unclear. The intraspecific genetic variability of P. caeruleum and chromosomal organization of its genome are insufficiently studied. For the first time, we analyzed NGS genomic data of P. caeruleum using ReapeatExplorer2/TAREAN/DANTE Pipelines. In its repeatome, we identified 66.08% of Class I retrotransposons; 0.57% of Class II transposons; 0.42% of ribosomal DNA; and 0.87% of satellite DNA (six high-confident and three low-confident putative satellite DNAs). FISH chromosome mapping of seven tandem DNAs was carried out in two P. caeruleum varieties and two wild populations. Our results demonstrated the effectiveness of using satDNAs Pol_C 46 and Pol_C 33 in combination with 45S rDNA and 5S rDNA for precise chromosome identification. This approach allowed us to study intraspecific chromosomal variability and detect chromosomal rearrangements in the studied accessions of P. caeruleum, which could be related to the speciation process. These novel molecular markers are important for chromosome studies within Polemonium to clarify its taxonomy and phylogeny, and also, they expand the potential of different breeding programs.

Amaranthus L. includes valuable and promising crops of multi-purpose use, having high morphological diversity and complicated taxonomy. Their karyotypes and genomic relationships remain insufficiently studied. For the first time, a comparative repeatome analysis of Amaranthus tricolor L., Amaranthus cruentus L., and Amaranthus hypochondriacus L. was performed based on the high-throughput sequencing data obtained via bioinformatic analyses using the RepeatExplorer2/TAREAN/DANTE_LTR pipelines. Interspecific variations in the abundance of Ty1 Copia and Ty3 Gypsy retroelements, DNA transposons, and ribosomal and satellite DNA (satDNA) were detected. Based on fluorescence in situ hybridization (FISH), chromosome mapping of 45S rDNA, 5S rDNA, and satDNAs AmC9 and AmC70, and unique karyograms of A. tricolor, A. cruentus, Amaranthus paniculatus L., and A. hypochondriacus were constructed. The analysis of the interspecies genome diversity/similarity in DNA repeat contents, sequences of the identified satDNAs, and chromosome distribution patterns of the studied molecular markers indicated that these species might also share a common evolutionary ancestor. However, the genomes of A. cruentus, A. paniculatus, and A. hypochondriacus were more similar compared to A. tricolor, which aligns with the previous phylogenetic data. Our results demonstrate that cytogenomic studies might provide important data on Amaranthus species relationships elucidating taxonomy and evolution of these valuable crops.

Polemonium L. (Polemoniaceae) is a widespread genus native to subarctic and arctic regions of the Northern Hemisphere. The taxonomy and genome relationships within Polemonium are still unclear. We analyzed genomes of three species from each Polemonium caeruleum and Polemonium pulcherrimum complex using bioinformatic analysis by RepeatExplorer2/TAREAN pipelines of next-generation sequencing data. The repeatomes of all studied species were similar in type and number of repeats. Satellite DNAs (satDNAs) demonstrated high sequence identity within the studied species. FISH chromosome mapping of 45S rDNA, 5S rDNA, and two satDNAs Pol_C 33 and Pol_C 46 allowed us to construct the species karyograms and assess the genome diversity within the P. caeruleum complex and P. pulcherrimum complex, and also confirm the taxonomic status of P. kiushianum as an independent species. Our findings demonstrate a close genomic relationship among the species from P. caeruleum and P. pulcherrimum complexes, indicating the presence of a common ancestral genome; additionally, our results provide cytogenetic evidence for the monophyletic origin of these sections and also complex evolutionary history of the genus Polemonium. The developed approach may be a valuable framework for further investigation of the chromosomal organization of karyotypes in other species of the genus Polemonium.