Vol 17, No 3 (2019)

Background. During the colonization of root and nodule tissues of legumes by rhizobia, bacterial cells are immersed in a plant extracellular matrix which includes arabinogalactan protein-extensins (AGPE).

Materials and methods. Immunogold electron microscopy with monoclonal antibodies MAC204 and MAC236 was used to analyse the distribution and abundance of epitopes of AGPE in wild-type and symbiotically defective pea mutants.

Results. In the nodules of the wild-type line SGE, both AGPE epitopes were detected to the same extent in the matrix of infection threads and infection droplets. In the nodules of the mutant line SGEFix−-1 (sym40), the level of labelling by MAC204 was significantly higher than with SGE in both infection threads and infection droplets, but the level of labelling by MAC236 was only increased in the infection droplets. In the mutant line SGEFix−-2 (sym33-3), a relatively high level of both epitopes was observed among all analysed genotypes. The double mutant line RBT3 (sym33-3, sym40) showed an intermediate level of labelling for both epitopes in infection threads compared with the parental mutants. In SGEFix−-1, an abnormal distribution of both epitopes was observed in the intercellular space matrix. The MAC204 epitope was found in the cell walls of SGEFix−-1 and in the infection thread walls of SGEFix−-2, whereas in RBT3 this epitope was detected in both types of walls.

Conclusions. The sym33-3 and sym40 mutations have different effects on the accumulation of AGPE epitopes recognised by MAC204 and MAC236. This indicates that both the Sym33 and the Sym40 genes affect the composition of AGPE in the matrix of infection threads and infection droplets.

Background. Polymorphism analysis was done for the core genome sequences of nodule bacteria of S. meliloti species in order to identify chromosomal types and to evaluate the occurrence of accessory elements (genomic islands) in them.

Materials and methods. Chromosomal studied loci were: betBC (marker M-I) and SMc04407-SMc04881 (marker M-II) both are related to metabolic processes and stress tolerance, and 16S-23S intergenic sequences (marker M-III) to search phylogenetical distance at intraspecies level.

Results. Significant differences between the occurrence of alleles of gene-markers M-I/M-II and MIII were determined between strains related to tested the 5 typical groups and 9 subgroups of strains differing by geographical region/source (nodule, soil) of isolation, as well as by salt tolerance. Four chromosomal types were identified among tested S. meliloti native isolates and a preference occurence of one of the three islands Rm1021 in links with particular chromosomal type was shown. The significant prevalence of strains with particular chromosomal type was shown for S. meliloti populations native to centers of alfalfa diversity at the NE of Caucasus, as well as at NE of Kazakhstan (Aral sea related region), as well as in agrocenoses. Conclusion. It was predicted that strains inherited altered markers M-I/M-II may belong to divergent clonal lines occured in both centers of alfalfa diversity, while strains with altered sequences of all three markers could be a representatives of a new S. meliloti biovar(s), the formation of which is occurred much more intensively at the modern center of the introgressive hybridization of alfalfa at NE of Kazakhstan.

Hypothermia, drought, salinity and heavy metals are the most widespread stress factors negatively affecting plant growth and development. Plants respond to these stress factors on molecular, cellular, and physiological levels through the complicated mechanisms of signal perception and transduction, subsequently inducing various defense mechanisms. Transcription factors controlling the expression of numerous defense proteins are the most significant abiotic stress reaction regulators. Mainly, the negative environmental influence activates the AP2/ERF, WRKY, MYB, NAC, bZIP transcription factors. The numerous transcription factors genes can be used in genetic engineering of agricultural crops resistant to abiotic stress. These genes are also of great interest in marker assisted selection of cultivated plants. This review is dedicated to description of transcription factors and their genes, involved in plant response to hypothermia, drought, salinity and heavy metals.

Based on the materials of 23 fur-bearing animal farms of the Russia for different periods of years, a comparative assessment of the reproductive capacity of sable and mink females of standard breeds (wild type) has been carried out. It was established that during intrabreeding differentiation according to the overall color of the hair coat (almost black, black-brown, dark brown and chestnut), the lowest reproduction level is characterized by darker females of sable, which are a significant increase in the number of them, mated with male, but not given offspring (barren females). According to the results of interbreed comparisons of sables and minks, parallelism was found in the variability of the reproductive capacity of females, which is manifested in the fact that, in contrast to relatively light animals, animals that are dark in color are characterized by a greater number of barren females and low fecundity.

The review describes the molecular mechanisms and biological effects of bisphenol A exposure, which is a chemical (ecotoxicant) that destroys the endocrine system and has epigenetic toxicity.

The review provides information on environmental factors affecting the level of miR-638 in humans, potential target genes of this micro-RNA (according to “TargetScanHuman”), diseases and metabolic pathways which potentially regulated miR-638, as well as clinical and experimental data confirming the involvement of miR-638 in the developing a wide range of multifactorial diseases. The data presented in the review expand the understanding of the pathogenesis of various diseases of a multifactorial nature and determine new strategies for studying gene-environment interactions that are important for the formation of health.