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Salinization and drought are the most important abiotic stress factors causing significant impact to the agriculture of Uzbekistan. To eliminate the negative consequences of the drying of the Aral Sea, large-scale works are currently being conducted on this territory to create protective forest plantations of halophytic trees and shrubs. An important issue in the protection of forest plantations is the isolation, identification and monitoring of phytopathogenic fungi associated with these forest plantations. The study's objective was to isolate Alternaria fungi from Haloxylon aphyllum (Minkw.) Iljin, Tamarix hispidaWilld., T.ramossisima Ledeb. and to also apply a diagnostic marker using PCR assays to detect and identify Alternaria pathogens in these plants. As a result of the study, 10 strains of Alternaria fungi were isolated from plant samples of black saxaul - Haloxylon aphyllum, and two tamarisk species - Tamarix hispida, Tamarix ramossisima. The dominant species was: Alternaria tenuissima (Kunze) Wiltshire. β-tubulin gene was used as a molecular marker to distinguish and identify Alternaria spp in 34 leaf samples of Haloxylon aphyllum, Tamarix hispida and Tamarix ramossisima. The primer set used in the PCR assay was shown to be capable of detecting the presence of Alternaria in the leaves. Therefore, a β-tubulin-based diagnostic marker can be widely applied for monitoring of Alternaria infecting a wide-range of halophytic trees and shrubs in the protective forest plantations. [ABSTRACT FROM AUTHOR]

Wheat has long been considered an important plant in the national economy, and several phytopathogenic viruses have been studied to infect this plant, the most common of which is Barley yellow dwarf virus. BYDV causes great economic damage in agriculture. This article presents the results of research conducted on the BYDV-PAV strain isolated from Uzbekistan. As a result of the conducted research, plant samples (leaf, root, stem) collected from wheat fields in Tashkent region were diagnosed by BYDV-PAV RT-PCR method using special primers based on nucleotide sequence of ORF3 gene of BYDV-PAV coat protein. As a result of research, the presence of the BYDV-PAV strain was found in the collected samples, and the nucleotide sequence of BYDV-PAV was studied. BLASTN and phylogenetic analysis of the virus isolate based on the determined nucleotide sequence showed the highest genetic similarity by 99.81% with the Morocco PAV-type isolate MA9501 (AJ007929.1) while the lowest similarity rate was 87.10% with the Tunisian isolate PAV-TN4 (JX402456.1). [ABSTRACT FROM AUTHOR]