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The use of high-throughput sequencing (HTS) technology has led to significant progress in the identification of many viruses and their genetic variants. In this study, we used the HTS platform to sequence small RNAs (sRNAs) of grapevine to study the virome. Isolation of RNA was performed using symptomatic grapevines collected from commercial vineyards in Krasnodar Krai in 2017–2018. To determine the viromes of vineyards, we used an integrated approach that included a bioinformatic analysis of the results of sRNA HTS and the molecular method RT-PCR, which made it possible to identify 13 viruses and 4 viroids. Grapevine leafroll-associated virus 4 (GLRaV-4), Grapevine Syrah Virus-1 (GSyV-1), Raspberry bushy dwarf virus (RBDV), Australian grapevine viroid (AGVd), and Grapevine yellow speckle viroid 2 (GYSVd-2) were identified for the first time in Russia. Out of 38 samples analyzed, 37 had mixed infections with 4–11 viruses, indicating a high viral load. Analysis of the obtained sequences of fragments of virus genomes made it possible to identify recombination events in GLRaV-1, GLRaV-2, GLRaV-3, GLRaV-4, GVT, GPGV, GRSPaV, GVA, and GFLV. The obtained results indicate a wide spread of the viruses and a high genetic diversity in the vineyards of Krasnodar Krai and emphasize the urgent need to develop and implement long-term strategies for the control of viral grapevine diseases.

Fertilizers based on complexes of chelated trace elements are the most common and effective agricultural products for the induction of protective-compensatory and other adaptive reactions of plants. The influence of various leaf treatments technologies with chelated micronutrient fertilizers application on the stability of grapes is studied under increasing abiotic and biotic environment factors within the Taman Peninsula (Russia) considering the content of proline, photosynthetic pigments (chlorophylls and carotenoids), total water in the leaves, as well as the development of infectious drying of clusters and leaf spotting reduction due to the treatment. The new optimized scheme application on the chelated micronutrient fertilizers showed a predominantly positive effect on the grape plants adaptation to high-temperature drought and fungal diseases susceptibility, as well as essential increase of the average cluster weight and yield per hectare.

Viral diseases can seriously damage the vineyard productivity and the quality of grape and wine products. Therefore, the study of the species composition and range of grapevine viruses is important for the development and implementation of strategies and tactics to limit their spread and increase the economic benefits of viticulture. In 2014–2019, we carried out a large-scale phytosanitary monitoring of Russian commercial vineyards in the Krasnodar region, Stavropol region and Republic of Crimea. A total of 1857 samples were collected and tested for the presence of Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine virus A (GVA), Grapevine leafroll-associated virus-1 (GLRaV-1), Grapevine leafroll-associated virus-2 (GLRaV-2), Grapevine leafroll-associated virus-3 (GLRaV-3), Grapevine fanleaf virus (GFLV), and Grapevine fleck virus (GFkV) using RT-PCR. Out of all samples tested, 54.5% were positive for at least one of the viruses (GRSPaV, GVA, GLRaV-1, GLRaV-2, GLRaV-3, GFLV, GFkV) in the Stavropol region, 49.8% in the Krasnodar region and 49.5% in the Republic of Crimea. Some plants were found to be infected with several viruses simultaneously. In the Republic of Crimea, for instance, a number of plants were infected with five viruses. In the Krasnodar region and the Republic of Crimea, 4.7% and 3.3% of the samples were predominantly infected with both GFkV and GRSPaV, whereas in the Stavropol region, 6% of the selected samples had both GLRaV-1 and GVA infections. We carried out a phylogenetic analysis of the coat protein genes of the detected viruses and identified the presence of GVA of groups I and IV, GRSPaV of groups BS and SG1, GLRaV-1 of group III, GLRaV-2 of groups PN and H4, GLRaV-3 of groups I and III. The results obtained make it possible to assess the viral load and the distribution of the main grapevine viruses on plantations in the viticultural zones of Russia, emphasizing the urgent need to develop and implement long-term strategies for the control of viral diseases of grapes.

Species of the genera Bacillus Cohn and Pseudomonas Migula are successfully used as biocontrol agents for many mycopathogens, including Alternaria sp. To assess the bacteria antagonistic potential against Alternaria sp, we used the method of counter cultures on various nutrient media – universal and specialized. Of the 24 bacterial strains of the genus Bacillus , 18 strains were developed antagonistic activity to Alternaria sp. after 10 days of co-cultivation on the Tylona-3 medium. The maximum sterile zone (8.0 mm) was formed by bacterial strains (R-9, 5B-1, 01 cor f Bacillus sp.). 3 strains of 9 bacteria of the genus Pseudomonas , developed antagonistic activity to Alternaria sp. on Kinga B medium - 14-3 Pseudomonas sp., Oif 2-1 Pseudomonas sp., 14-4 Pseudomonas sp. The maximum antibiotic activity on potato-sucrose agar was established in strains 3-3 Bacillus sp., and K 1-1 Bacillus sp. (sterile zone 7.5 mm). All the tested bacteria most often caused one sign of antagonism – antibiosis.

The assessment of the diversity of fungic communities and the study of the bioindicational significance of mycological parameters is relevant for the biomonitoring of ampelocenoses. We studied the quantitative and qualitative composition of saprotrophic micromycetes communities associated with annual shoots of wild and cultivated grape plants. Studies have shown that the number of saprotrophic micromycetes associated with an annual vine is different depending on the place of sampling and ranges from 232.9 … 3203.2 thousand CFU / g dry matter on wild grapes and within 118.9 … 344.1 thousand CFU/g dry matter on cultivated grapes. The highest density indicators of fungal populations - 1119.7 and 3203.2 CFU/g dry matter - were recorded on a vine from forest ecotopes, the lowest indicator of 118.9 CFU/g dry matter was recorded on a vine from ampelocenosis, On wild vines, major share in the studied of fungic communities was occupied by hyphal or mold fungi, on average their share was 95.1%, while yeast occupied 4.2%, and yeast-like fungi - 0.7% of the complex. On cultivated vines, hyphal fungi also occupied the largest part in the structure of fungic communities, but their share was 1.7 times less than on wild plants. Yeast (26.5%) and yeast-like fungi (18.4%) took much larger share.

Oxydifficidin is a natural polyketide antibiotic that has long been recognized as a ribosome-targeting agent that inhibits protein synthesis. In this paper, we describe strain EV17 and compare its complete genome sequence with that of the previously characterized strain K-3618 and the difficidin biosynthetic gene cluster (BGC) combined with mass spectrometry to elucidate the production of oxydifficidin by these strains. Toeprinting and small fluorescent peptide assays showed that isolated oxydifficidin induces a generalized inhibition of translation at every step of elongation in protein biosynthesis. In previous studies, it has been demonstrated that oxydifficidin targets bL12 protein. Although spontaneous mutations conferring resistance to oxydifficidin in ribosomal protein bL12 located relatively close to the thiostrepton binding site on uL11, our data show that oxydifficidin binding does not interfere with thiostrepton, thereby refining previous findings about its putative ribosomal target. We are the first to show that this compound does not affect eukaryotic translation and has two orders of magnitude lower effect on eukaryotic cells compared to bacteria. These facts are important to further investigate its potential as a bioprotectant against phytopathogens or even as a therapeutic agent.