DNA barcoding is a standard and efficient method, frequently used for identification, discrimination and discovery of new species. Although this approach is very useful for classifying the world's biodiversity, little is known about its usefulness in barcoding at lower taxonomic level and its discrimination rate for closely related species, like conifers. In this study, we compared the genetic variation of eight chloroplast DNA barcode regions (matK, rbcL, trnH-psbA, trnL-trnF, rpl20-rps18, trnV, ycf1, ycf2) in 17 conifers - three closely related pines from Pinus mugo complex and 14 more distant conifers representing two genera and four sections of the Pinaceae family. The discrimination rate for a single and for multiple DNA barcode regions analyzed in this study was estimated using the Tree-Building and PWG-Distance methods. The usefulness of the DNA barcoding approach for analyzing and resolving taxonomic inconsistency among closely related and more phylogenetically distant conifers was evaluated and discussed.

Dracaena draco, which belongs to the genus Dracaena, is an endemic succulent of the Canary Islands. Although it is one of the most popular and widely grown ornamental plants in the world, little is known about its genomic variability. Next generation sequencing, especially in combination with advanced bioinformatics analysis, is a new standard in taxonomic and phylogenetic research. Therefore, in this study, the complete D. draco chloroplast genome (cp) was sequenced and analyzed in order to provide new genomic information and to elucidate phylogenetic relationships, particularly within the genus Dracaena. The D. draco chloroplast genome is 155,422 bp, total guanine-cytosine (GC) content is 37.6%, and it has a typical quadripartite plastid genome structure with four separate regions, including one large single copy region of 83,942 bp length and one small single copy region of 18,472 bp length, separated by two inverted repeat regions, each 26,504 bp in length. One hundred and thirty-two genes were identified, 86 of which are protein-coding genes, 38 are transfer RNAs, and eight are ribosomal RNAs. Seventy-seven simple sequence repeats were also detected. Comparative analysis of the sequence data of various members of Asparagales revealed mutational hotspots potentially useful for their genetic identification. Phylogenetic inference based on 16 complete chloroplast genomes of Asparagales strongly suggested that Dracaena species form one monophyletic group, and that close relationships exist between D. draco, D. cochinchinensis and D. cambodiana. This study provides new and valuable data for further taxonomic, evolutionary and phylogenetic studies within the Dracaena genus.

Long-term seed storage is important for protecting both economic interests and biodiversity. The extraordinary properties of seeds allow us to store them in the right conditions for years. However, not all types of seeds are resilient, and some do not tolerate extreme desiccation or low temperature. Seeds can be divided into three categories: (1) orthodox seeds, which tolerate water losses of up to 7% of their water content and can be stored at low temperature; (2) recalcitrant seeds, which require a humidity of 27%; and (3) intermediate seeds, which lose their viability relatively quickly compared to orthodox seeds. In this article, we discuss the genetic bases for desiccation tolerance and longevity in seeds and the differences in gene expression profiles between the mentioned types of seeds.

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<p>The primary purpose of this study is to evaluate the sequence variation for two regions of chloroplast DNA in a collection of 27 taxonomically well-annotated clonal lines of <em>Marchantia polymorpha</em> sensu lato derived from European populations. We attempted to develop molecular markers so as to identify three taxa usually recognized as subspecies. We sequenced two regions: the <em>rps4</em> gene along with the <em>rps4-trnT</em> intergenic spacer and an intron of the tRNA^Gly (UCC) gene. Samples of <em>Marchantia paleacea</em> ssp. <em>diptera</em> from Japan were used for comparative purposes.</p><p>Three haplotypes (MA, MB, and MC) were identified for the species, and almost all sequence divergence between subspecies was found to occur at the level of 0.0023–0.0032 substitutions per site. The sequence divergence between <em>M. polymorpha</em> and <em>M. paleacea</em> was tenfold greater (0.0331–0.0340). We did not detect any differences between <em>M. paleacea</em> and homologous sequences from the reference chloroplast genome of <em>M. polymorpha</em> obtained from the GeneBank (NC_001319). It was confirmed that the cell suspension line A-18 used for the sequencing of the full chloroplast genome in 1986 was incorrectly taxonomically annotated.</p>

The Pinus mugo complex includes several dozen closely related European mountain pines. The discrimination of specific taxa within this complex is still extremely challenging, although numerous methodologies have been used to solve this problem, including morphological and anatomical analyses, cytological studies, allozyme variability, and DNA barcoding, etc. In this study, we used the seed total protein (STP) patterns to search for taxonomically interesting differences among three closely-related pine taxa from the Pinus mugo complex and five more distant species from the Pinaceae family. It was postulated that STP profiling can serve as the backup methodology for modern taxonomic research, in which more sophisticated analyses, i.e., based on the DNA barcoding approach, have been found to be useless. A quantitative analysis of the STP profiles revealed characteristic electrophoretic patterns for all the analyzed taxa from Pinaceae. STP profiling enabled the discrimination of closely-related pine taxa, even of those previously indistinguishable by chloroplast DNA barcodes. The results obtained in this study indicate that STP profiling can be very useful for solving complex taxonomic puzzles.