Issn 305-9397. Ғылым және білім. 2022. №1-1 (66) issn 2305-9397
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170 during the wheat earing period. It is likely that insects, especially sucking pests, such as grass aphids, wheat thrips, and cicadas, play a certain role in the spread of the infection [8]. Rapid and accurate identification of bacterial diseases is critical in many areas, including biodiversity conservation, environmental monitoring, prevention and control of bacterial pathogens, quarantine objects and human health. Currently, when studying the biodiversity of animals, plants, and microorganisms, along with the traditional approach, methods of molecular genetic research are used. Molecular methods have high versatility, relative simplicity, and quality of research for solving various diagnostic problems, including the detection and identification of pathogens [9]. The advantages of molecular methods for microorganism identification are the speed and accuracy of determining the species and strain of the pathogen; the possibility of determining the species without isolating the bacterium into a pure culture. Universality, high sensitivity, and relative ease of performance have made molecular biology methods, such as PCR and sequencing, indispensable for solving various diagnostic problems, such as direct detection and identification of pathogens, molecular typing, and the study of the properties of pathogenic microorganisms [10]. Basically, ribosomal genes present in all organisms are used for genomic diagnostics of bacteria. Sequences of highly variable DNA ITS regions have long been an ideal target for the genetic identification of bacteria. Huge databases such as GenBank ( https://www.ncbi.nlm.nih.gov/genome/browse/#!/prokaryotes/ ) are currently available for bacteria identification. Although bacterial identification methods based on classical microbiological tests are the «gold standard», molecular diagnostics based on DNA region sequencing are indispensable. Recently, along with the highly variable ITS region, other genes, such as tandem repeats have been used [11, 12, 13]. With the development of science and the improvement of material and technical equipment, new identification technologies appear, in particular, next-generation genomic sequencing (NGS), DNA chips, and mass spectrometry [14]. Despite the information content, sensitivity, and productivity of such analysis methods, their main significant drawback, which limits their widespread use, is the cost of equipment and reagents, which reduces accessibility for the main producers of agricultural products. In this regard, there is an obvious need to develop accessible and, at the same time, highly specific express methods for identifying plant pathogens. One such method is Loop-mediated Isothermal Amplification (LAMP) DNA/RNA (http://loopamp.eiken.co.jp/e/lamp/), which uses DNA polymerases with effective activity unwinding DNA strands, such as Bst 2.0 DNA Polymerase. The possibility of amplification and visualization of its products without the use of special equipment greatly expands the possibilities of identification [15]. Additionally, a new PCR option for DNA amplification is the Xtreme Chain Reaction (XCR) Extreme Polymerase Reaction ( https://fluoresentric.com/principal-of-xcr/ ), which is a patented ultra- fast PCR DNA amplification variant incorporating a unique thermal cycling technology, design of PCR primers, and selection of a target for amplification. Using standard enzymes and reagents, the XCR reaction is adapted to any existing PCR instruments, reagents, and fluorescent probes. The efficiency and specificity of this method are much higher than traditional methods since instead of denaturing the entire genomic DNA, XCR uses only the specific denaturation temperature of a particular target DNA, which leads to a minimum of the formation of non-specific products. This approach speeds up DNA amplification because the temperature range between denaturation and annealing varies from 5°C to 15°C. In addition, the time required for PCR is inversely proportional to the concentrations of critical reagents. With an increase in the concentration of primers and polymerase several times, the cycle time is reduced. With a specificity of 90%, amplification can take as little as 5 minutes. This method will make it possible to identify pathogens in a very short time and practically under isothermal conditions, which is important in identifying quarantine pathogens, various monitoring studies, and customs control of the quality of food products in cases of export or import [16]. Bacterioses caused by phytopathogenic bacteria pose a serious threat to agroecosystems and affect global food security. Phytopathogenic bacteria have a high evolutionary potential that allows |