Taxonomic Structure Research Articles

How host species and body part determine the microbial communities of five ambrosia beetle species.

The ambrosia beetles are farming insects that feed mainly on their cultivated fungi, which in some occasions are pathogens from forest and fruit trees. We used a culture-independent approach based on 16S and 18S rRNA gene metabarcoding analysis to investigate the diversity and composition of the bacterial and fungal communities associated with five ambrosia beetle species: four species native to America (Monarthrum dimidiatum, Dryocoetoides capucinus, Euwallacea discretus, Corthylus consimilis) and an introduced species (Xylosandrus morigerus). For the bacterial community, the beetle species hosted a broad diversity with 1,579 amplicon sequence variants (ASVs) and 66 genera, while for the fungal community they hosted 288 ASVs and 39 genera. Some microbial groups dominated the community within a host species or a body part (Wolbachia in the head-thorax of E. discretus; Ambrosiella in the head-thorax and abdomen of X. morigerus). The taxonomic composition and structure of the microbial communities appeared to differ between beetle species; this was supported by beta-diversity analysis, which indicated that bacterial and fungal communities were clustered mainly by host species. This study characterizes for the first time the microbial communities associated with unexplored ambrosia beetle species, as well as the factors that affect the composition and taxonomic diversity per se, contributing to the knowledge of the ambrosia beetle system.

Exploring Hyponyms: Taxonomic Structure and Semantic Features

The article examines the concept of hyponyms, focusing on their taxonomic structure and semantic features. It delves into the hierarchical relationship between hyponyms and hypernyms, exploring how specific terms are classified under broader categories. Additionally, it investigates the distinguishing characteristics and properties that differentiate hyponyms within specific domains, providing insights into their organization and semantic differentiation based on taxonomic structure.

Simple, inexpensive, and rapid approach to detect changes in the structure of soil free-living nematodes.

A general limitation of ecological investigations based on nematodes is related to the difficult and time-consuming taxonomic identification of species. Therefore, nematologists are investing many efforts to develop alternative approaches as proxies applicable in biomonitoring assessment. Recently, an alternative method that combines morpho-functional traits was proposed for detecting assemblage changes of marine nematodes. In view of the promising results, it was tested the same approach to document taxonomic structure changes of soil free-living and plant parasitic nematodes. Specifically, this attempt was carried out using three data sets that include studies from various European regions and different types of ecosystems: forests, grasslands and maize crops. Multivariate statistical analysis revealed that the simple combination of the four traits (i.e., buccal cavity cuticularization occurrence, amphideal fovea size and shape, morphology of the cuticle and pharynx) in a single code number perfectly mirrors the taxonomic structure trends of the nematode assemblage at genus level. Therefore, we predict that similar results can be also obtained by directly encoding nematode specimens with the selected traits and we point to new important advances if this procedure can be coupled with advanced machine learning.

Zooplankton of Volga River reservoirs: structure, abundance and dynamics

The taxonomic structure and spatial distribution of the late-summer zooplankton in the Volga River from the upper Ivankovo reservoir to Volga Delta near Astrakhan during the period 2020–2021 were studied. Zooplankton biomass in the most of the Volga reservoirs was dominated by cladoceran Daphnia galeata and copepod Mesocyclops leuckarti (up to 45–84%). However different dominant species were observed in the Volgograd reservoir. Cladocerans Chydorus sphaericus and Bosmina cf. longispina formed there up to 43% of the total zooplankton biomass. Rotifers and Ponto-Caspian copepod Heteroscope caspian are dominated in the Volga River below the dam of the Volzhskaya hydropower plant (56% and 18% of the total zooplankton biomass respectively). Among the invasive species, most abundant are East Asian copepod Thermocyclops taihokuensis (up to 230 thsd. ind./m3 and locally 90% of the total biomass) and North American copepod Acanthocyclops americanus (up to 86 thsd. ind./m3 and 35% of the total biomass). The maximum abundance of the zooplankton (0.8–1.6 g/m3) was observed in the Upper Volga reservoirs while the minimum abundance (0.1–0.2 g/m3) – in the Lower Volga. The maximum abundance of zooplankton (0.8–3.3 g/m3) was recorded in the mouth areas of the reservoir tributaries, while the minimum abundance (0.1–1.4 g/m3) – in the pelagic zone of the reservoirs. A decrease in the zooplankton community biomass from Upper to Lower Volga was observed in all biotopes. A negative correlation between the community abundance and daily water inflow into the reservoirs and a positive correlation between the community abundance and water temperature were revealed. Long-term variations in zooplankton biomass and their relationship with water body trophic state, thermal and oxygen regimes were discussed.

Ambivalence of planktonic invaders and transformation of communities

The ambivalence of planktonic invaders has been studied using the example of ecosystem effects of the invasive cladoceran Cercopagis pengoi (Ostroumov, 1891) in the Vistula Lagoon of the Baltic Sea. The influence of the invader on the taxonomic structure and productivity of plankton is studied. It is discovered that, in the long term, the predation pressure of C. pengoi on zooplankton has decreased; the abundance, biomass, and production of the dominant species Rotifera, Cladocera, and Copepoda also declined. The negative impact of C. pengoi on the planktonic community is reflected in a reduction in the food supply of juvenile Baltic herring and other planktivorous fish. The wide ecological niche of Cercopagis contributes to the expansion of its range, which can lead to a reduction in populations of phytophagous crustaceans, increased water blooms, and the further deterioration of the food supply of fish.

Effect of a cyclonic eddy on phytoplankton: A bioassay experiment

AbstractCyclonic eddies often increase the primary productivity of marine ecosystems. However, the study of their influence on the taxonomic structure and productivity of plankton is complex due to the short‐term and mesoscale nature of the action of eddies. In a laboratory bioassay experiment, we simulated two mechanisms of eddy's effect on the deep phytoplankton maximum: an increase in the upward flow of deep nutrients and illumination. Doubling of nutrient additions compared to control increased chlorophyll's specific growth rate (SGR) 1.7‐fold over 12 days while doubling the light intensity increased SGR by 3.5 times. During the first 4 days of the experiment, at the exponential growth stage, SGR of carbon biomass was maximum with the simultaneous doubling of nutrients and light (0.44 day−1). It was statistically significantly higher than at increased nutrients but not light. These results suggest that nutrient deficiencies were less crucial for phytoplankton growth than light. The increase in the phytoplankton biomass was mainly due to the growth of a large‐celled diatom Pseudosolenia calcar‐avis. It showed the highest SGR (1.15–1.28 day−1) at increased nutrients and/or light, resulting in high wet biomass of 2–3 g m−3 over 4 days. The ecological meaning of the obtained results is as follows. First, in the eddy, where the deep phytoplankton maximum is located close to the nutricline, its rise to more illuminated layers results in higher phytoplankton growth than the shortening distance to the nutricline. Second, increases in the upward flow of nutrients and light intensity, separate or simultaneous, stimulate the rapid reproduction of large‐celled diatoms that increase the carbon‐to‐chlorophyll ratio by 2–4 times. Third, exposure to a typical Black Sea mesoscale cyclonic eddy can lead to phytoplankton blooms in the thermocline within a few days.

A new approach to describe the taxonomic structure of microbiome and its application to assess the relationship between microbial niches.

Data from microbiomes from multiple niches is often collected, but methods to analyse these often ignore associations between niches. One interesting case is that of the oral microbiome. Its composition is receiving increasing attention due to reports on its associations with general health. While the oral cavity includes different niches, multi-niche microbiome data analysis is conducted using a single niche at a time and, therefore, ignores other niches that could act as confounding variables. Understanding the interaction between niches would assist interpretation of the results, and help improve our understanding of multi-niche microbiomes. In this study, we used a machine learning technique called latent Dirichlet allocation (LDA) on two microbiome datasets consisting of several niches. LDA was used on both individual niches and all niches simultaneously. On individual niches, LDA was used to decompose each niche into bacterial sub-communities unveiling their taxonomic structure. These sub-communities were then used to assess the relationship between microbial niches using the global test. On all niches simultaneously, LDA allowed us to extract meaningful microbial patterns. Sets of co-occurring operational taxonomic units (OTUs) comprising those patterns were then used to predict the original location of each sample. Our approach showed that the per-niche sub-communities displayed a strong association between supragingival plaque and saliva, as well as between the anterior and posterior tongue. In addition, the LDA-derived microbial signatures were able to predict the original sample niche illustrating the meaningfulness of our sub-communities. For the multi-niche oral microbiome dataset we had an overall accuracy of 76%, and per-niche sensitivity of up to 83%. Finally, for a second multi-niche microbiome dataset from the entire body, microbial niches from the oral cavity displayed stronger associations to each other than with those from other parts of the body, such as niches within the vagina and the skin. Our LDA-based approach produces sets of co-occurring taxa that can describe niche composition. LDA-derived microbial signatures can also be instrumental in summarizing microbiome data, for both descriptions as well as prediction.

Culturable yeast diversity in urban topsoil influenced by various anthropogenic impacts.

In urban ecosystems, processes associated with anthropogenic influences almost always lead to changes in soil micromycete complexes. The taxonomic structure of soil micromycete complexes is an important informative parameter of soil bioindication in the ecological control of urban environments. Unicellular fungi, such as culturable yeasts, are a very suitable and promising object of microbiological research for monitoring urban topsoil. This review aims to give an overview of the yeast communities in urban topsoil in different areas of Moscow (heating main area, household waste storage and disposal area, highway area) and to discuss the changes in the taxonomic structure of culturable yeast complexes depending on the type and intensity of anthropogenic impact.

Fungi in groundwater springs and wells in the Moscow region

The number, species composition and taxonomic structure of fungal biota in the groundwater of natural springs and wells in the Moscow region were determined by сultural method. The number of fungi was low, on average from 10 to 300 colony-forming units (CFU) in 1 liter of water. 6–16 species were isolated from the water of one source or well, and totally 46 species were isolated from 6 studied objects. These were representatives of phylum Mucoromycota class Mucoromycetes (Absidia cylindrospora var. nigra, Mucor circinelloides, M. hiemalis,Rhizopus stolonifer), phylum Ascomycota class Eurotiomycetes (15 species of the generaAspergillusandPenicillium), Sordariomycetes (13 species of the generaAcremonium, Chaetomium, Fusarium, Myrothecium, Plectosphaerella, Trichoderma), Dothideomycetes (Alternariaalternata, A. nobilis, Amorocoelophoma cassia, Cladosporium cladosporioides, C. sphaerospermum) and – Saccharomycetes (Candida solani, C. zeylanoides, Galactomyces pseudocandidus) and phylum Basidiomycota class Tremellomycetes (Mrakia gelida, Vishniacozyma victoriae) and Agaricomycetes (Phlebia acerina, Psathyrella candolleana, Thanatephorus cucumeris). The established taxonomic structure of fungal biota in the waters of natural springs and wells of the Moscow metropolis is similar to that found in the groundwater of other regions, including of groundwater at the depths of several hundred meters. The possibilities of adaptation of micromycetes to existence in ground water, the sources of its contamination and the need for mycological criteria for assessing water quality are discussed.

Fecal Microbiota and Feeding Habitats of Nomadic Indigenous Animals (Deer, Yak, Sheep and Camel) in Baikal Siberia (Russia)

In the vast expanse of Baikal Siberia, indigenous nomadic animal groups have been conserved, grazing on pastures throughout the year. It is believed that the fecal microbiota of these diverse nomadic animal species is unique to each species and closely tied to their feeding environments. We conducted a pioneering comparative analysis of the taxonomic structure and the diversity of fecal microbiota in indigenous nomadic animals inhabiting Baikal Siberia. Our study encompassed 20 deer, 23 yaks, 24 camels, and 29 sheep, using high-throughput 16S rRNA gene profiling. In the fecal microbiota of these animals, we observed a predominant presence of the phyla Bacillota, Bacteroidota, and Verrucomicrobiota, collectively comprising over 88% of the microbial communities. Moreover, these proportions exhibited variations according to the host species. The unculturable Bacillota UCG-005 and UCG-010 are the key groups for all animals. However, at the genus level, distinctive compositions of fecal microbiota were discernible within each animal group. We identified a total of 37 dominant genera across the fecal samples from these four animal species. Principal component analysis (PCA) and cluster analysis demonstrated that the fecal microbiota composition clustered among individuals of the same animal species. Linear discriminant analysis effect size (LEfSe) indicated that camels exhibited higher abundances of the family Akkermansiaceae and the uncultured clostridial lineage UCG-010, while deer featured Lachnospiraceae; sheep had Ruminococcaceae; and yaks displayed Monoglobaceae, Bacteroidaceae, and methanogenic archaea from the family Methanobacteriaceae as distinctive marker taxa. Our studies showed that the studied nomadic animals feed mainly on plants belonging to the families Poaceae, Cyperaceae, Asteraceae, and Rosaceae. Our research indicated that the identity of the host species and, to a lesser degree, their diets and habitats, significantly shape the composition of fecal microbiota in these studied nomadic ruminant animals.

TypeTaxonScript: sugarifying and enhancing data structures in biological systematics and biodiversity research.

Object-oriented programming (OOP) embodies a software development paradigm grounded in representing real-world entities as objects, facilitating a more efficient and structured modelling approach. In this article, we explore the synergy between OOP principles and the TypeScript (TS) programming language to create a JSON-formatted database designed for storing arrays of biological features. This fusion of technologies fosters a controlled and modular code script, streamlining the integration, manipulation, expansion, and analysis of biological data, all while enhancing syntax for improved human readability, such as through the use of dot notation. We advocate for biologists to embrace Git technology, akin to the practices of programmers and coders, for initiating versioned and collaborative projects. Leveraging the widely accessible and acclaimed IDE, Visual Studio Code, provides an additional advantage. Not only does it support running a Node.js environment, which is essential for running TS, but it also efficiently manages GitHub versioning. We provide a use case involving taxonomic data structure, focusing on angiosperm legume plants. This method is characterized by its simplicity, as the tools employed are both fully accessible and free of charge, and it is widely adopted by communities of professional programmers. Moreover, we are dedicated to facilitating practical implementation and comprehension through a comprehensive tutorial, a readily available pre-built database at GitHub, and a new package at npm.

A Historical-Cognitive Linguistics Study of Caesar’s Characterization in Shakespearean Plays

By using “polysemy model” of semantic change theories in historical linguistics, “mapping” and “conceptual integration” of metaphor, and “classical taxonomic structure” of categorization theories in cognitive linguistics, and literary conventions of structuralist poetics in literary studies, this article studies Caesar’s characterization in Shakespeare’s Julius Caesar and other plays. After analyzing the semantic change of “Caesar” and different characters’ cognition on Caesar in the fictional world created by dialogues and character interactions, this article discovers that the negotiation and exchange between the totalculture in 1599 and Shakespeare’s personal artistic pursuit propel Shakespeare to create an ambiguous but great and unique Caesar in Julius Caesar, within the two kinds of intertexts consisting of different characters’ discourses scattered in other Shakespearean plays, Caesar’s ambiguity is eliminated, and his greatness and uniqueness are strengthened, and it is in his skillful maneuver of different literary conventions in characterizing Caesar that Shakespeare’s great literary competence is manifested.

Taxonomic structure in a set of abstract concepts.

A large portion of human knowledge comprises "abstract" concepts that lack readily perceivable properties (e.g., "love" and "justice"). Since abstract concepts lack such properties, they have historically been treated as an undifferentiated category of knowledge in the psychology and neuropsychology literatures. More recently, the categorical structure of abstract concepts is often explored using paradigms that ask participants to make explicit judgments about a set of concepts along dimensions that are predetermined by the experimenter. Such methods require the experimenter to select dimensions that are relevant to the concepts and further that people make explicit judgments that accurately reflect their mental representations. We bypassed these requirements by collecting two large sets of non-verbal and implicit judgments about which dimensions are relevant to the similarity between pairs of 50 abstract nouns to determine the representational space of the concepts. We then identified categories within the representational space using a clustering procedure that required categories to replicate across two independent data sets. In a separate experiment, we used automatic semantic priming to further validate the categories and to show that they are an improvement over categories that were defined within the same set of abstract concepts using explicit ratings along predetermined dimensions. These results demonstrate that abstract concepts can be characterized beyond their negative relation to concrete concepts and that categories of abstract concepts can be defined without using a priori dimensions for the concepts or explicit judgments from participants.

Stream fish assemblages in the Eastern Amazon: the role of small tetras (Characidae) in alpha diversity and taxonomic structure

Abstract Wallacean shortfalls in knowledge about biodiversity, especially in the Amazon biome, can only be addressed by increasing sampling efforts in focal areas. The objective of this study was to describe the fish fauna of streams associated with four protected areas in the Eastern Amazon. These areas include the Tapajós (Parque Nacional da Amazônia, Parque Nacional do Jamanxim) and Trombetas drainages (Floresta Nacional Saracá-Taquera), and Tapajós/Xingu interfluve (Reserva Biológica Nascentes da Serra do Cachimbo), state of Pará, Brazil. In the 99 stream reaches surveyed, 176 fish species were recorded. Almost a third of the species and specimens belong to the Characidae family, predominantly represented by small tetras (known as piabasor lambaris). One threatened species (Harttia dissidens) was registered. Of the total richness, 24 species were singletons and associated with specific habitats. The highest taxonomic distinctness was observed for Floresta Nacional Saracá-Taquera, while streams within the Parque Nacional da Amazônia exhibited the greatest taxonomic distinctness variation. Compared to existing records in scientific collections covering stream fish fauna in watersheds of up to 4,300 hectares in Pará, our study added the record of eight other genera and identified relevant areas for additional surveys.

Cyanobacteria of Ukraine: Taxonomic Structure in 2024

Systematics of cyanobacteria experiencing a period of rapid changes associated with the appearance of new molecular markers, the improvement of molecular phylogenetic methods, and widely used polyphasic approach. Many characters previously considered taxonomically significant have been found to have repeatedly arisen in different phylogenetic lineages during the evolution of cyanobacteria, and genetic diversity of taxa often greatly exceeds their morphological diversity. Attempts to combine the approaches of morphological taxonomy with molecular data did not solve the problem, although they helped to systematize the results of floristic studies. The emergence of a new classification system of cyanobacteria (NCSC), in which the authors relied on genomic phylogeny, determined the need to revise the taxonomic structure of the flora of cyanobacteria of Ukraine, since its last published version, based on taxonomic information as of 2021, no longer corresponds to the modern classification of cyanobacteria. The paper analyzes the main innovations of the NCSC and the changes that have occurred with the leading taxa of the Ukrainian flora, and also provides an updated taxonomic structure of the cyanobacteria of Ukraine.

Responses of soil physico-chemical properties, structure of the microbial community and crop yields to different fertilization practices in Russia's conventional farming system.

The use of fertilizers affects not only the soil fertility and crop yield, but also significantly changes the taxonomic structure of the soil microbiocenosis. Here, based on stationary field experiment, we studied the influence of organo-mineral fertilizer (ОМF), modified by bacteria Bacillus subtilis, H-13 in comparison with different fertilizer systems (organic, mineral, organo-mineral) on (i) crop yield, (ii) physical and chemical properties, and (iii) alpha and beta diversity of the microbial community Albic Retisol (Loamic, Aric, Cutanic, Differentic, Ochric). The studies were carried out against the background of liming (рНКCl - 5.9) and without it (рНКCl - 5.1). The use of only one cattle farmyard manure was less effective than its co-application with mineral fertilizers in half doses. A similar effect was obtained when applying ОМF. In addition, the use of OMF contributes to a significant increase in the reserves of soil organic carbon in the soil layer 0-20 cm by 18%-32%. Using high-throughput sequencing of the 16S rRNA variable V4 gene sequence libraries, 10.759 taxa from 456 genera were identified, assigned to 34 fila (31 bacterial and 3 archaeotic. Unilateral application of mineral fertilizers leads to a significant decrease in the alpha diversity of the structure of soil microbial communities (OTE (other things equal) and Shannon index). A clear clustering of the microbiota was found in the variants with and without the introduction of сattle farmyard manure. It is revealed that the taxonomic structure of the microbiocenosis is formed under the influence of two main factors: crop rotation culture and applied fertilizers. The type of cultivated crop determines the dynamics of the microbiota at the level of larger taxa, such as domains, and fertilizers affect the structure of the microbial community at a lower taxonomic level (phyla, orders, bloodlines). On the basis of the Deseq analysis, marker taxa were identified, according to the share participation of which it is possible to determine the type of cultivated crop and fertilizers used in the experiment. Understanding the dynamics of taxa association and other influential factors can lead to the creation of universal systems of metagenomic indication, where tracking the dynamics of microbial communities will allow for a comprehensive assessment of the agroecological state of soils and timely decisions to prevent their degradation.

Insights from single-strain and mixed culture experiments on the effects of heatwaves on freshwater flagellates.

The increasing frequency and intensity of heatwaves driven by climate change significantly impact microbial communities in freshwater habitats, particularly eukaryotic microorganisms. Heterotrophic nanoflagellates are important bacterivorous grazers and play a crucial role in aquatic food webs, influencing the morphological and taxonomic structure of bacterial communities. This study investigates the responses of three flagellate taxa to heatwave conditions through single-strain and mixed culture experiments, highlighting the impact of both biotic and abiotic factors on functional redundancy between morphologically similar protist species under thermal stress. Our results indicate that temperature can significantly impact growth and community composition. However, density-dependent factors also had a significant impact. In sum, stabilizing effects due to functional redundancy may be pronounced as long as density-dependent factors play a minor role and can be overshadowed when flagellate abundances increase.

Changes in Phytoplankton of the Irpin River (Ukraine) as a Result of Military Activities in Its Basin

Phytoplankton structure was studied in a comparative aspect (before and after the beginning of military activities) in the section of the Irpin River belonging to a large lowland rivers flowing in silicate rocks. On the whole, 132 algal species of seven divisions were found in the water column of the Irpin River during the period of investigations. Bacillariophyta and Chlorophyta were highly diverse in their species composition (37.1 and 31.1% of the total number of species). The distribution of plankton algae at the studied stations even within the same massif of surface waters was non-uniform in terms of species composition (the Sorensen coefficient of community similarity on the average was 37%), species richness (18-49 species), cell numbers (1930 thousand cells/L - 24,450 thousand cells/L), and biomass (2.118 mg/L - 20.374 mg/L). Almost different algal species dominated at various stations (14 species among 20 dominated only at one station). Compared to the previous period of investigations (2018), the number of plankton algal species in the studied section of the Irpin River somewhat increased (from 121 to 132). Phytoplankton taxonomic structure also somewhat changed. The contribution of Bacillariophyta increased from 22.3 to 37.1% and that of Cyanoprokaryota - from 9.1 to 12.1%. In this case, the contribution of Chlorophyta decreased from 47.1 to 37.1%. The quantitative indices of phytoplankton development increased. The maximum numbers increased from 19,480 thousand cells/L to 24,450 thousand cells/L, whereas the maximum biomass - from 5.143 mg/L to 20.374 mg/L. As a consequence of the impact of military activities on phytoplankton of the Irpin River, it is possible to consider an increase in the number of its species, the maximum numbers and biomass, as well as the contribution of water bloom forming blue-green algae in the estuarine section of the Irpin River due to the disturbance of hydromorphology and the income of an additional amount of nutrients from flooded territories, which can lead to the formation of such a negative phenomenon as water bloom in this section of the river.

Traços funcionais dos Nematoda são uma boa ferramenta para visualizar uma sucessão ecológica em substratos artificiais em um reservatório do semiárido brasileiro?

Abstract Aim The Brazilian tropical semiarid is a biome with small freshwater ecosystems, often intermittent, acting as a mosaic in constant transformation between dry and rainy seasons. Meiobenthic communities play crucial roles in these environments, and understanding their colonization and succession processes is essential to comprehend how these organisms’ structure in a defaunated habitat. In addition to the traditional taxonomic approach, functional traits provide valuable insights into the dynamics of these processes. In this study, we tested the following hypotheses: i) although meiofauna consists of microscopic organisms with limited active dispersion, they quickly colonize new substrates, increasing in abundance, richness, and diversity; ii) functional traits of freshwater Nematoda are a good tool for view an early succession on hard artificial substrate in a lentic reservoir. Methods We placed 27 ceramic plates in a reservoir in the Brazilian semiarid and randomly sampled three replicates each week over nine weeks. Weekly differences in community abundance, richness, and diversity were tested with one-way ANOVA and pairwise PERMANOVA. Results Nematoda predominated in the first week, with Rotifera taking over from the second week of the experiment. No differences were observed in the Nematode taxonomic structure over the weeks. There was an increase in the functional complexity of the Nematoda community over time, as indicated by the maturity index and trophic structure. Colonizers/persistents emerged quickly in the first week. Deposit feeders dominated, but an increase in trophic diversity was observed with the growing presence of chewers over the weeks. Conclusions This study highlights that the functional traits of Nematoda represent a robust tool for assessing ecological succession in freshwater lentic environments in the tropical semiarid.

Genetic and phenotypical diversity of Pseudomonas syringae population in the Russian Federation.

Proteobacteria comprising species of Pseudomonas syringae group cause diseases of many plants around the world. The phytopathogen has a complex taxonomic structure, which is constantly being revised due to the emergence of new molecular and biochemical diagnostic methods. Here for the first time, we describe the genetic and phenotypic diversity of 57 strains of Pseudomonas syringae isolated from affected soybeans, cereals, sunflowers, and other plants in the Russian Federation from 1950 to 2019. Genetic diversity was assessed by Multi Locus Sequence Analysis (MLSA) using fragments of the genes of glyceraldehyde-3-phosphate dehydrogenase (gapdh), the DNA-directed RNA polymerase subunit D (rpoD), gyrase (topoisomerase) B subunit (gyrB), and citrate synthase I (gltA). The synthesis of syringomycin and coronatine by bacteria was assessed by the reaction of susceptible yeast culture, seedlings of barley, tomato, and sunflower, and by presence of toxin genes confirmed by PCR test. The pathogenicity of the strains was confirmed on seedlings of dicotyledonous and monocotyledonous plants of peas, soybean, sunflowers, barley and wheat, as the most affected crops. The sensitivity of bacteria to 10 antibiotics of the main mechanisms of activity and two bactericidal commercial products was tested by standard disc method. The obtained results showed a high genetic homogeneity of the Russian population of P. syringae, which infects various agricultural crops, and an increase in the proportion of antibiotic-resistant strains over the years.