Comparative Characterization of <i>Pseudoroegneria libanotica</i> and <i>Pseudoroegneria tauri</i> Based on Their Repeatome Peculiarities

Pseudoroegneria species play an important role among Triticeae grasses, as they are the putative donors of the St genome in many polyploid species. Satellite repeats are widely used as a reliable tool for tracking evolutionary changes because they are distributed throughout the genomes of plants. The aim of our work is to perform a comparative characterization of the repeatomes of the closely related species Ps. libanotica and Ps. tauri, and Ps. spicata was also included in the analysis. The overall repeatome structures of Ps. libanotica, Ps. tauri, and Ps. spicata were similar, with some individual peculiarities observed in the abundance of the SIRE (Ty1/Copia) retrotransposons, Mutator and Harbinger transposons, and satellites. Nine new satellite repeats that have been identified from the whole-genome sequences of Ps. spicata and Ps. tauri, as well as the CL244 repeat that was previously found in Aegilops crassa, were localized to the chromosomes of Ps. libanotica and Ps. tauri. Four satellite repeats (CL69, CL101, CL119, CL244) demonstrated terminal and/or distal localization, while six repeats (CL82, CL89, CL168, CL185, CL192, CL207) were pericentromeric. Based on the obtained results, it can be assumed that Ps. libanotica and Ps. tauri are closely related species, although they have individual peculiarities in their repeatome structures and patterns of satellite repeat localization on chromosomes. The evolutionary fate of the identified satellite repeats and their related sequences, as well as their distribution on the chromosomes of Triticeae species, are discussed. The newly developed St genome chromosome markers developed in the present research can be useful in population studies of Ps. libanotica and Ps. tauri; auto- and allopolyploids that contain the St genome, such as Thinopyrum, Elymus, Kengyilia, and Roegneria; and wide hybrids between wheat and related wild species

Study and Physical Mapping of the Species-Specific Tandem Repeat CS-237 Linked with 45S Ribosomal DNA Intergenic Spacer in Cannabis sativa L.

Hemp (Cannabis sativa L.) is a valuable crop and model plant for studying sex chromosomes. The scientific interest in the plant has led to its whole genome sequencing and the determination of its cytogenetic characteristics. A range of cytogenetic markers (subtelomeric repeat CS-1, 5S rDNA, and 45S rDNA) has been mapped onto hemp&rsquo;s chromosomes by fluorescent in situ hybridization (FISH). In this study, another cytogenetic marker (the tandem repeat CS-237, with a 237 bp monomer) was found, studied, and localized on chromosomes by FISH. The signal distribution and karyotyping revealed that the CS-237 probe was localized in chromosome 6 with one hybridization site and in chromosome 8 with two hybridization sites, one of which colocalizes with the 45S rDNA probe (with which a nucleolus organizer region, NOR, was detected). A BLAST analysis of the genomic data and PCR experiments showed that the modified CS-237 monomers (delCS-237, 208 bp in size) were present in the intergenic spacers (IGSs) of hemp 45S rDNA monomers. Such a feature was firstly observed in Cannabaceae species. However, IGS-linked DNA repeats were found in several plant species of other families (Fabaceae, Solanaceae, and Asteraceae). This phenomenon is discussed in this article. The example of CS-237 may be useful for further studying the phenomenon as well as for the physical mapping of hemp chromosomes

Association of High-Molecular-Weight Glutenin Subunits with Grain and Pasta Quality in Spring Durum Wheat (<i>Triticum turgidum</i> spp. <i>durum</i> L.)

Spring durum wheat is an important raw material for producing diverse products such as couscous, bulgur, bread, and pasta. The quality of the dough is significantly influenced by high-molecular-weight glutenins, the allelic status of which depends on the region and breeding program. In this study, a collection of 69 cultivars and promising lines of durum wheat were analyzed for the allelic state of Glu-A1 and Glu-B1 using SDS-PAGE and KASP PCR markers. Protein and gluten content, volume increase index, pasta breaking strength, general pasta estimation, SDS, and gluten index were measured for each accession based on a two-year field experiment in the Krasnodar region. The analysis revealed that the Glu-B1al, Glu-B1d, and Glu-B1z* alleles positively influence gluten index, with Glu-B1al increasing protein, gluten, and SDS content, whereas Glu-B1d decreased these traits. Glu-B1e, on average, decreased the gluten index and SDS value but did not affect protein or gluten content. The role of alleles affecting the gluten index and protein content in ensuring the quality of pasta in durum wheat breeding is discussed