Ecological genetics

BACKGROUND: Assessing the genetic structure of populations of rare and vulnerable species provides useful information for developing conservation strategies.

AIM: The aim of the study was to study the genetic structure of Caucasotachea vindobonensis populations in the south of the Central Russian Upland using SSR markers.

MATERIALS AND METHODS: Genetic structure of the populations was studied using eight microsatellite markers, first identified by the authors for the species under study. Fragment analysis of PCR products was carried out on an automatic capillary DNA sequencer Nanophore 05 (Russia). A total of 498 individuals from 24 populations were studied.

RESULTS: A total of 59 alleles were isolated in the eight studied SSR loci, of which 21 (36%) turned out to be private. At the same time, private alleles were found in eleven studied populations, which is 46% of their total number. According to the data obtained, the effective number of alleles (A_e) averaged 1.6 ± 0.06, the Shannon index (I) was 0.45 ± 0.03, and the level of expected heterozygosity (H_e) was 0.27 ± 0.021. A high level of spatial subdivision of population gene pools was noted (F_st = 0.47 ± 0.08) with a fairly low level of gene flow (N_m = 1.15 ± 0.91). PCA analysis showed that the populations of the central and eastern parts of the south of the Central Russian Upland form a closely related group, different from other populations of the region. Calculation of the effective abundance using the LD method showed that Ne varies in different groups of snails from 0.6 to infinity.

CONCLUSIONS: Populations of C. vindobonensis in the south of the Central Russian Upland live in conditions of significant isolation, as evidenced by the high degree of differentiation of the studied groups. The analysis of principal components based on genetic distances according to Nei and Wright’s F-statistics indicate a pronounced division of populations in the study area into two clusters, which is probably associated with the historical features of landscape formation. Calculation of effective numbers indicates the high viability of the majority of the studied populations. At the same time, some groups of snails are clearly in a depressed state, which is reflected in low levels of genetic diversity and their effective size.

BACKGROUND: Parastagonospora nodorum and P. pseudonodorum are known for their ability to produce necrotrophic effectors that play an important role in micromycete pathogenicity. Fungal strains characterized by the presence of effector genes will be used to create artificial infectious backgrounds to identify sources and donors of resistance to fungal diseases. Selected varieties and lines that are donors of recessive alleles snn1 and snn3, which control plant resistance to fungal toxins PtrTox1 and PtrTox3, are recommended for inclusion in programs for breeding wheat for resistance to septoriosis pathogens.

AIM: The aim of the work is to assess the populations of the fungi Parastagonospora nodorum and P. pseudonodorum in 2023 based on the presence of effector genes, as well as to identify alleles of Snn1/snn1, Snn3/snn3 genes that control the sensitivity or resistance of wheat to PtrTox1 and PtrTox3 toxins.

MATERIALS AND METHODS: Infectious samples were collected in 2023 from spring wheat leaves. In addition, the material for the study was 2 varieties and 23 lines of spring soft wheat of local selection. Using the molecular markers Xfcp624 and Xcfd20, the presence of the Snn1 and Snn3-B1 alleles, which control sensitivity to the fungal toxins PtrTox1 and PtrTox3, was detected.

RESULTS: Using molecular screening, ToxA and Tox1 genes were identified in genotypes of P. pseudonodorum isolates; Tox3 and Tox267 in P. nodorum isolates. 2 varieties of spring soft wheat and 11 hybrid lines carry a recessive allele snn1, which protects against the phytopathogen toxin PtrTox1; wheat variety Tambovchanka and 2 hybrid lines carry the recessive allele snn3 on chromosome B1, which confers resistance to the fungal toxin PtrTox3.

CONCLUSIONS: The ToxA gene was found only among monoconidial isolates of P. pseudonodorum species obtained from leaves of spring soft wheat of Lebedushka variety. As a result of molecular screening, the Tox1 gene was identified among 70 P. pseudonodorum isolates (43,21% of those studied). The presence of the Tox3 and Tox267 genes was established in 30 isolates of P. nodorum species obtained from plant samples of spring durum wheat Donskaya Elegiya. Using the PCR method, donors of the snn1 and snn3 genes were identified.

BACKGROUND: Heterotrophic cell cultures are widely used as a model in plant biology. During a culture cycle the composition of the medium changes: the sucrose and other substrates are depleted, metabolism products are accumulated and the density increases. Finally, arrest of a growth is followed by cell death in a short time. These processes are accompanied with physiological alterations, corresponding to senescence.

AIM: To resolve metabolic features of tobacco cells in growing and stationary senescent suspension cultures VBI-0.

MATERIALS AND METHODS: Nicotiana tabacum VBI-0 cells were cultured in suspension MS medium supplied with 3% sucrose. Cells were sampled at 7^th day, during intensive growth, and at 28^th day, when the culture was in the stationary phase. The GC-MS method was used to profile the metabolites.

RESULTS: Sucrose depletion in media caused starvation of heterotrophic tobacco cell culture and was associated with a decrease in the accumulation of free amino acids. At the same time, the level of pentoses and complex sugars, including sucrose, increased, while the levels of glucose and fructose were not changed significantly and levels of hexose phosphates decreased. During culture senescence cells showed higher levels of accumulation of malate, pyruvate and some other carboxylates.

CONCLUSIONS: The metabolomic data indicate that culture senescence was associated with a drop in amino acids metabolism, a decrease in the activity of the upper part of glycolysis, and the accumulation of complex sugars, pentoses and carboxylates.

BACKGROUND: A common non-selective systemic herbicide Roundup (Glyphosate, active ingredient N-phosphonomethylglycine, N-PMG) is used to control perennial weeds. It is necessary to assess the hazard of the products of photochemical decomposition of N-FMG formed under the influence of solar UV and ozone.

AIM: Using lux-biosensors based on Escherichia coli, studying the ability of N-FMG photochemical degradation products to induce oxidative stress in bacterial cells.

MATERIALS AND METHODS: The work used the active substance of the herbicide Roundup N-phosphonomethylglycine (N-PMG), biosensors E. coli (pSoxS-lux), E. coli (pKatG-lux). UV radiation, Mass spectrometry.

RESULTS: Using biosensors, it was shown that the products of photochemical decomposition of N-PMG (2-(N-hydroxymethyl-hydroxyamine) ethanoic acid) cause an increase in the concentration of superoxide anion radical and H₂O₂ in E. coli cells, which induces oxidative stress in the bacterial cell.

CONCLUSIONS: The photochemical decomposition product of N-PMG (2-(N-hydroxymethyl-hydroxyamine) ethanoic acid) induces the formation of superoxide anion radical and H₂O₂ in bacterial cells.

BACKGROUND: Reactions associated with the geochemical nitrogen cycle occurring in the soil have a decisive effect on the level of nitrogen availability for green plants. Microorganisms that catalyze them are of interest from the point of view of developing mechanisms for managing soil fertility. In this paper, we focused on bacterial genera associated with nitrogen cycle processes in chernozem soils of the Belgorod Region of Russia.

AIM: To determine the list and quantitative ratios of bacterial genera whose representatives are able to participate in the fixation of atmospheric nitrogen, nitrification and denitrification in the chernozems of the forest-steppe zone of the European part of Russia.

MATERIALS AND METHODS: Samples of arable and non-arable chernozems of three subtypes were collected in June and August 2022. Microbiological profiling based on high-throughput sequencing of amplicons of V3 and V4 region of the 16S rRNA gene with subsequent computational processing of the results was used in the work.

RESULTS: 6 genera of nitrogen-fixing bacteria were found, as well as a group undifferentiated by means of the method used, including genus Rhizobium. 8 genera involved in the first and 5 genera involved in the second stage of nitrification were also found. 7 genera have been found whose representatives are capable of denitrification, without taking into account nitrogen-fixing bacteria, which are also capable of carrying out this process.

CONCLUSIONS: Among the bacteria capable of fixing atmospheric nitrogen in the chernozems of the Belgorod region, the genus Bradyrhizobium dominates. Among the nitrifiers performing the first stage of nitrification, Ellin6067 and MND1 from the family Nitrosomonadaceae predominate. The second stage of nitrification is carried out mainly by bacteria of the genus Nitrospira. Of the potential denitrifies, along with nitrogen-fixing genera possessing this ability, representatives of the genera Rubrobacter and Pseudomonas are the most numerous. The study does not claim to give a complete list of organisms that carry out key chemical transformations of nitrogen compounds in chernozems, however, it allows us to name their important participants.

Drought poses a significant challenge to the sustainable development of modern agriculture and to the achievement of high crop yields. Water deficit causes osmotic stress and triggers plant physiological responses characterized by reduced water potential, diminished stomatal conductance, and decreased photosynthetic efficiency. Long-term adaptation to osmotic stress entails intricate metabolic rearrangements, leading to the accumulation of osmoprotectants, activation of antioxidant systems, and increased biosyntheses of stress-protective proteins. The severity and duration of drought, along with plant genotype and developmental stage, influence the plant response to stress, consequently affecting crop yield and quality. Particularly in the context of legumes, which are crucial for human and animal nutrition, understanding adaptive strategies to water deficit is essential for the cultivation of drought-resistant genotypes, primarily because these crops predominantly thrive in semi-arid regions. Proteomics and metabolomics approaches, in turn, serve as valuable tools, offering critical insights into the molecular dynamics governing plant responses to drought stress. Furthermore, the use of reliable drought simulation models is imperative for the effective evaluation of legume response to water scarcity, aiding the cultivation of drought-tolerant varieties. This review highlights the perspectives of utilizing different osmotic stress models to investigate proteome and metabolome alteration within seeds of food legumes.