A Comparative Study of the Three Cucumber Cultivars Using Fluorescent Staining and Fluorescence In Situ Hybridization

Interstitial Telomeric-like Repeats (ITR) in Seed Plants as Assessed by Molecular Cytogenetic Techniques: A Review

The discovery of telomeric repeats in interstitial regions of plant chromosomes (ITRs) through molecular cytogenetic techniques was achieved several decades ago. However, the information is scattered and has not been critically evaluated from an evolutionary perspective. Based on the analysis of currently available data, it is shown that ITRs are widespread in major evolutionary lineages sampled. However, their presence has been detected in only 45.6% of the analysed families, 26.7% of the sampled genera, and in 23.8% of the studied species. The number of ITR sites greatly varies among congeneric species and higher taxonomic units, and range from one to 72 signals. ITR signals mostly occurs as homozygous loci in most species, however, odd numbers of ITR sites reflecting a hemizygous state have been reported in both gymnosperm and angiosperm groups. Overall, the presence of ITRs appears to be poor predictors of phylogenetic and taxonomic relatedness at most hierarchical levels. The presence of ITRs and the number of sites are not significantly associated to the number of chromosomes. The longitudinal distribution of ITR sites along the chromosome arms indicates that more than half of the ITR presences are between proximal and terminal locations (49.5%), followed by proximal (29.0%) and centromeric (21.5%) arm regions. Intraspecific variation concerning ITR site number, chromosomal locations, and the differential presence on homologous chromosome pairs has been reported in unrelated groups, even at the population level. This hypervariability and dynamism may have likely been overlooked in many lineages due to the very low sample sizes often used in cytogenetic studies.

Live-Cell CRISPR Imaging in Plant Cells with a Telomere-Specific Guide RNA

Chromatin organization is highly dynamic in living cells. Therefore, it might have a regulatory role over biological mechanisms like transcription, replication, and DNA repair. To elucidate how these mechanisms are regulated, it is required to establish imaging methods to visualize the chromatin dynamic in living cells. Here, we provide a protocol for a live plant cell imaging technique based on application of two orthologs of the bacterial clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) from Streptococcus pyogenes and Staphylococcus aureus. This technique uses the inactive variants of Cas9 combined with different fluorescent proteins (GFP and mRuby) and telomere-specific guide RNA to target telomeric repeats in Nicotiana benthamiana. Our immuno-FISH data revealed that signals arising from the CRISPR/dCas9 method are specifically belonging to telomeric regions.

Next generation sequencing and omics in cucumber (Cucumis sativus L.) breeding directed research

In the post-genomic era the availability of genomic tools and resources is leading us to novel generation methods in plant breeding, as they facilitate the study of the genotype and its relationship with the phenotype, in particular for complex traits. In this study we have mainly concentrated on the Cucumis sativus and (but much less) Cucurbitaceae family several important vegetable crops. There are many reports on research conducted in Cucurbitaceae plant breeding programs on the ripening process, phloem transport, disease resistance, cold tolerance and fruit quality traits. This paper presents the role played by new omic technologies in the creation of knowledge on the mechanisms of the formation of the breeding features. The analysis of NGS (NGS-next generation sequencing) data allows the discovery of new genes and regulatory sequences, their positions, and makes available large collections of molecular markers. Genome-wide expression studies provide breeders with an understanding of the molecular basis of complex traits. Firstly a high density map should be created for the reference genome, then each re-sequencing data could be mapped and new markers brought out into breeding populations. The paper also presents methods that could be used in the future for the creation of variability and genomic modification of the species in question. It has been shown also the state and usefulness in breeding the chloroplastomic and mitochondriomic study.