The main number of genome editing events in plant objects obtained during the last decade with the help of specific nucleases zinc finger (ZFN), transcription activator-like effector nucleases (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas are the microindels causing frameshift and subsequent gene knock-out. The knock-ins of genes or their parts, i.e., the insertion of them into a target genome region, are between one and two orders of magnitude less frequent. First and foremost, this is associated with the specific features of the repair systems of higher eukaryotes and the availability of the donor template in accessible proximity during double-strand break (DSB) repair. This review briefs the main repair pathways in plants according to the aspect of their involvement in genome editing. The main methods for increasing the frequency of knock-ins are summarized both along the homologous recombination pathway and non-homologous end joining, which can be used for plant objects.

Two lines of transgenic carrot plants producingMycobacterium tuberculosisproteins (ESAT6 and CFP10) have been constructed. The target proteins are present in carrot storage roots at a level not less than 0.056% of the total storage protein (TSP) for ESAT6 and 0.002% of TSP for CFP10. As has been shown, oral immunization of mice induces both the cell-mediated and humoral immunities. These data suggest that the proteins in question are appropriate as a candidate edible vaccine against tuberculosis.

Most the pharmaceutical proteins are derived not from their natural sources, rather their recombinant analogs are synthesized in various expression systems. Plant expression systems, unlike mammalian...

Tuberculosis remains one of the major infectious diseases, which continues to pose a major global health problem. Transgenic plants may serve as bioreactors to produce heterologous proteins including antibodies, antigens, and hormones. In the present study, a genetic construct has been designed that comprises theMycobacterium tuberculosisgenescfp10, esat6anddIFNgene, which encode deltaferon, a recombinant analog of the humanγ-interferon designed for expression in plant tissues. This construct was transferred to the carrot (Daucus carotaL.) genome byAgrobacterium-mediated transformation. This study demonstrates that the fusion protein CFP10-ESAT6-dIFN is synthesized in the transgenic carrot storage roots. The protein is able to induce both humoral and cell-mediated immune responses in laboratory animals (mice) when administered either orally or by injection. It should be emphasized thatM. tuberculosisantigens contained in the fusion protein have no cytotoxic effect on peripheral blood mononuclear cells.

Cytomixis is a poorly studied process of nuclear migration between plant cells. It is so far unknown what drives cytomixis and what is the functional state of the chromatin migrating between cells. Using immunostaining, we have analyzed the distribution of posttranslational histone modifications (methylation, acetylation, and phosphorylation) that reflect the functional state of chromatin in the tobacco microsporocytes involved in cytomixis. We demonstrate that the chromatin in the cytomictic cells does not differ from the chromatin in intact microsporocytes according to all 14 analyzed histone modification types. We have also for the first time demonstrated that the migrating chromatin contains normal structures of the synaptonemal complex and lacks any signs of apoptosis. As has been shown, the chromatin migrating between cells in cytomixis is neither selectively heterochromatized nor degraded both before its migration to another cell and after it enters a recipient cell as micronuclei. We also showed that cytomictic chromatin contains marks typical for transcriptionally active chromatin as well as heterochromatin. Moreover, marks typical for chromosome condensation, synaptonemal complex formation and key proteins required for the formation of bivalents were also detected at migrated chromatin.

The development and improvement of molecular biology methods have led to the creation of new technologies that make it possible to modify plant genomes by transferring and integrating into the genomes’ heterologous genes from various expression systems (genetic engineering), as well as inducing knockouts of one or more target genes of interest (genomic editing). The development of genome-editing methods is a new milestone in the development of modern breeding methods and certainly relies on the knowledge and technologies developed for transgenesis. This review will discuss issues related to the advantages and disadvantages of both technologies for improving the economically valuable traits of important crops.