The Development of Populus alba L. and Populus tremula L. Species Specific Molecular Markers Based on 5S rDNA Non-Transcribed Spacer Polymorphism

The Populus L. genus includes tree species that are botanically grouped into several sections. This species successfully hybridizes both in the same section and among other sections. Poplar hybridization widely occurs in nature and in variety breeding. Therefore, the development of poplar species’ specific molecular markers is very important. The effective markers for trees of the Aigeiros Duby section have recently been developed using the polymorphism of 5S rDNA non-transcribed spacers (NTSs). In this article, 5S rDNA NTS-based markers were designed for several species of the Leuce Duby section. The alb9 marker amplifies one fragment with the DNA matrix of P. alba and P. × canescens (natural hybrid P. alba × P. tremula). The alb2 marker works the same way, except for the case with Populus bolleana. In this case, the amplification of three fragments was observed. The tremu1 marker amplification was detected with the DNA matrix of P. tremula and P. × canescens. Thus, the developed markers may be applied as a useful tool for P. alba, P. tremula, P. × canescens, and P. bolleana identification in various areas of plant science such as botany, dendrology, genetics of populations, variety breeding, etc

Development of 5S rDNA-Based Molecular Markers for the Identification of Populus deltoides Bartr. ex Marshall, Populus nigra L., and Their Hybrids

Populus L. is a tree genus that includes species with a high ability for interspecies hybridization. This process takes place in nature, and is used in poplar breeding. As а result, species identification in poplar populations and plantations is very difficult. In this study, a molecular marker system was developed for the identification of the most significant poplar species (P. nigra L. and P. deltoids Bartr. ex Marshall). The basis of the system is a polymorphism in non-transcribed spacers (NTSs) of 5S rDNA. The species-specific molecular markers were tested on a number of species and hybrids of poplars. It was shown that the marker system is a powerful tool for species identification, hybrid analysis, parent identification, and poplar breeding

The Development of New Species-Specific Molecular Markers Based on 5S rDNA in Elaeagnus L. Species

The Elaeagnus L. species are trees and bushes that mainly grow in temperate zones of Western Europe; Minor, Central, and Southeast Asia; the Far East; and North America. Some species are used as fruit or ornamental plants and have economic value. Problems with the identification of species in the Elaeagnus genus by molecular genetical methods arise in the study of populations, systematics, breeding, and other areas of plant science and practice. Recently, the polymorphism of 5S ribosomal DNA non-transcribed spacers (5S rDNA NTSs) in Elaeagnaceae Adans. has been described. The results were used in our study as a basis for development of new species-specific molecular markers for some members of the Elaeagnus genus. The author’s method was applied for finding regions that were potentially applicable for species-specific primer design. As a result, some species-specific molecular markers were developed for Elaeagnus angustifolia L., E. commutata Bernh., E. pungens Thunb., and E. multiflora Thunb. These markers were tested in a range of samples and showed the presence of amplified fragments in lanes of the marked species only. Samples of other species showed no amplifications. Thus, the developed markers may be useful for the species identification of the studied Elaeagnus plants in botanical, dendrological, and genetic research (especially in a leafless period of year), as well as in breeding and hybridization experiments

A Comparative Study of 5S rDNA Non-Transcribed Spacers in Elaeagnaceae Species

5S rDNA is organized as a cluster of tandemly repeated monomers that consist of the conservative 120 bp coding part and non-transcribed spacers (NTSs) with different lengths and sequences among different species. The polymorphism in the 5S rDNA NTSs of closely related species is interesting for phylogenetic and evolutional investigations, as well as for the development of molecular markers. In this study, the 5S rDNA NTSs were amplified with universal 5S1/5S2 primers in some species of the Elaeagnaceae Adans. family. The polymerase chain reaction (PCR) products of five Elaeagnus species had similar lengths near 310 bp and were different from Shepherdia canadensis (L.) Nutt. and Sh. argentea (Pusch.) Nutt. samples (260 bp and 215 bp, respectively). The PCR products were cloned and sequenced. An analysis of the sequences revealed that intraspecific levels of NTS identity are high (approximately 95–96%) and similar in the Elaeagnus L. species. In Sh. argentea, this level was slightly lower due to the differences in the poly-T region. Moreover, the intergeneric and intervarietal NTS identity levels were studied and compared. Significant differences between species (except E. multiflora Thunb. and E. umbellata Thunb.) and genera were found. Herein, a range of the NTS features is discussed. This study is another step in the investigation of the molecular evolution of Elaeagnaceae and may be useful for the development of species-specific DNA markers in this family

An Optimized Protocol for In Vitro Indirect Shoot Organogenesis of Impala Bronzovaya and Zanzibar Green Ricinus communis L. Varieties

The castor bean is an important industrial and ornamental crop. In the industry, it is used as a source of castor oil. Moreover, it has a large potential as a feed crop, because the seeds contain a high amount of protein. A main problem with castor bean use is the presence of toxins in the plants. Today, detoxification is carried out using various approaches, including biotechnological methods such as CRISPR/Cas9 technology. A successful application of these methods requires the availability of an efficient in vitro protocol for callus induction and shoot organogenesis. We present the results of in vitro condition optimization for two castor bean varieties (Impala Bronzovaya and Zanzibar Green). Eight different Murashige–Skoog (MS) culture media characterized by different plant growth regulator (PGR) combinations, as well as explant types (hypocotyls, cotyledonous leaves, and cotyledon petioles), were tested. The highest frequency of shoot organogenesis and average number per explant were observed during the cultivation of cotyledon petioles in both varieties on the Murashige and Skoog culture medium (MS) containing 1 or 2 mg/L of zeatin in combination with 0.1 mg/L of 3-indoleacetic acid (IAA). An optimized protocol for in vitro callus induction and shoot organogenesis may be used for biotechnological applications to obtain toxin-free castor bean, as well as Ricinus communis L. plants, with new ornamental traits and their combinations

Sex Chromosomes and Sex Determination in Dioecious Agricultural Plants

Unlike in animals, dioecy among flowering plants is a rare phenomenon. The vast majority of angiosperm species have a bisexual flower that combines male (androecium) and female (gynoecium) reproductive organs. However, about a quarter of species have dioecious flowers, which can be located within the same plant (monoecious) or on different plants (dioecious). The flower formation in dioecious plants is determined by various genetic mechanisms. They become more complex from the work of a single gene to the functioning of full-fledged heteromorphic sex chromosomes, which can directly affect sex differentiation or participate in the balance determination of sex (where the formation of male or female flower organs depends on the ratio of X chromosomes to autosomes, for example). In recent years, the development of sequencing techniques, bioinformatics, and molecular biology has led to an increase in interest in the sex determination mechanisms among plants. It is noteworthy that a significant number of dioecious plants have economic value. At the same time, dioeciousness often complicates the growing process. This fact increases the relevance of studies on dioecious crops. In this review, we attempt to summarize the current information on sex chromosomes and the mechanisms of sex determination in dioecious plants, concentrating on species with agricultural importance

Molecular cytogenetic characterization of the dioecious Cannabis sativa with an XY chromosome sex determination system.

Hemp (Cannabis sativa L.) was karyotyped using by DAPI/C-banding staining to provide chromosome measurements, and by fluorescence in situ hybridization with probes for 45 rDNA (pTa71), 5S rDNA (pCT4.2), a subtelomeric repeat (CS-1) and the Arabidopsis telomere probes. The karyotype has 18 autosomes plus a sex chromosome pair (XX in female and XY in male plants). The autosomes are difficult to distinguish morphologically, but three pairs could be distinguished using the probes. The Y chromosome is larger than the autosomes, and carries a fully heterochromatic DAPI positive arm and CS-1 repeats only on the less intensely DAPI-stained, euchromatic arm. The X is the largest chromosome of all, and carries CS-1 subtelomeric repeats on both arms. The meiotic configuration of the sex bivalent locates a pseudoautosomal region of the Y chromosome at the end of the euchromatic CS-1-carrying arm. Our molecular cytogenetic study of the C. sativa sex chromosomes is a starting point for helping to make C. sativa a promising model to study sex chromosome evolution