#transgenicplants

Abstract Wheat is a strategic agricultural crop in the world and plays a leading role in mankind’s food supply. Despite the generally increasing trend of its production, global climate changes, and the associated increase in the number of soil and air droughts during the growing season of plants, the development of new strategies in the adaptation of wheat to this abiotic stress factor, the action of which causes a decrease in yield, is necessary. Genetic engineering made it possible to increase the efficiency of creating new drought-resistant genotypes of wheat, and its application became a significant addition to the traditional selection of this crop. Recently, some progress has been made in identifying key regulators of drought tolerance in wheat, and new genes have been identified that confer resistance and improve plant growth and survival. The presented literature review provides examples of successful application of genetic engineering to improve wheat adaptation to drought. Genes involved in the biosynthesis of osmolytes, proteins, and enzymes that function as scavengers of reactive oxygen species, molecular chaperones, and ion transporters, as well as regulatory genes of transcription factors and protein kinases and used to increase drought resistance of wheat, were considered. Information on the physiological and biochemical characteristics of genetically modified plants with various built-in genes for testing their tolerance to water deficit in controlled or field conditions is summarized. The results of editing the wheat genome to improve its drought resistance are presented.

Abstract Currently, there are approximately 6500 species of viruses known in the world, among which more than 1500 are plant viruses. Most of them are capable of causing epiphytoties, which lead to decreased yields, reduced product quality, and sometimes put valuable commercial varieties or even entire plant species at risk of extinction. The global spread of viruses leads to the need to strengthen phytosanitary and quarantine restrictions, which requires additional financial costs. Understanding of viral biology and the principles of its propagation is a key factor in the formation of strategies and methods for combating these pathogens. Among the newest approaches are the genetic engineering technologies. Their use made it possible to create a number of plant varieties with increased resistance to viruses. However, the problem of creating virus-resistant plants still remains one of the most urgent since viruses acquire the ability to bypass defense mechanisms with time and there is a need to obtain new resistant varieties. There are several main approaches for obtaining of transgenic plants with increased resistance to viruses. They are based on RNA interference, resistance associated with viral capsid proteins, RNA-satellites, antisense RNAs, replicases, RNA-dependent RNA polymerase, the action of ribonucleases, ribosome-inactivating proteins, hammerhead ribozymes, miRNAs, plant antibodies, etc. One of the approaches to creating virus-resistant plants is the use of ribonuclease genes. The genes encoding ribonucleases have different origin and belong to a wide range of hosts: bacteria, fungi, plants, and animals. In particular, extracellular ribonucleases are able to cut nonspecifically molecules of viral RNA in apoplast that allows for creating plants with increased resistance to various plant viruses. This review is focused on the study of various genetic engineering approaches and the prospects of their use for the creation of virus-resistant plants. Emphasis is placed on the study of heterologous ribonuclease genes influence.

Abstract RNA interference (RNAi) is a new potential tool for plant breeding by introducing small noncoding RNA sequences with the possibility of silencing gene expression in a sequence-specific manner. The ability to decrease the expression of a certain gene provides the possibility of acquiring a new characteristic through the elimination or accumulation of certain plant traits, which leads to biochemical or phenotypic changes that the original plants do not have. A progress (reached over the past decades) in the application of RNAi for the creation of cereal crops with improved economically valuable traits is described in this literature review. The main stages of the mechanism of gene silencing mediated by short interfering RNAs (siRNAs), peculiarities of their biogenesis, mode of action, and distribution are briefly presented. Numerous examples of the development of different biotechnological approaches to the improvement of cereals using gene transformation and exogenous double-stranded RNA (dsRNA) molecules are summarized. The possibilities of using RNAi technology for changing the agronomic traits of plants, increasing the nutritional value and quality of the grain, and reducing the number of toxic compounds and allergens are highlighted. Considerable attention is paid to the practical results of different applications of RNAi to increase the resistance of grain crops to biotic stress factors (particularly, viruses, bacteria, fungi, pest insects, and nematodes). The examples of using siRNA-mediated RNAi to improve the cereal resistance to abiotic stresses (including drought and salinity) are given.