Vol 16, No 4 (2018)

Opinions, discussions
RNA interference in formation of the somatic genome of ciliates Paramecium and Tetrahymena
Nekrasova I.V., Potekhin A.A.

Ciliates are the model of choice to study RNA interference, the mechanism playing key role in biology of these protists. The genome scanning processes of two ciliates, Tetrahymena and Paramecium (Oligohymenophorea), leading to formation of the somatic genome from the chromosomes of the generative nucleus are compared in the review. Matching of several simulta neously present in one cell genomes is mediated by small RNAs and results in precise reproduction of maternal somatic genome in the sexual progeny.

Ecological genetics. 2018;16(4):5-22
Genetic basis of ecosystems evolution
Molecular genetic basis of biofilm formation as a component of Vibrio Cholerae persistence in water reservoirs of Russian Federation
Titova S.V., Monakhova E.V., Alekseeva L.P., Pisanov R.V.

Background. The problem of cholera remains acute for world health service and risks of importation of Vibrio cholerae strains from endemic countries to Russia do exist. Toxigenic strains (carrying cholera toxin genes ctxAB) can cause epidemic outbreaks of cholera and non-toxigenic (ctxAB-) – single or multiple cases of cholera-like diarrhea. Investigation of their ability to survive in water reservoirs in climatic conditions of middle latitudes by means of forming biofilms is essential for potential threat evaluation.

Materials and methods. Biofilm formation by 15 V. cholerae strains on abiotic surfaces was studied in microcosms with tap water and cover glasses. Identification of responsible genetic determinants in whole genome sequences and bioinformatics analysis were performed using BioEdit 7.2.5, BLASTN 2.2.29, Blastp and Vector NTI Advance 11 software.

Results. The strains investigated differed in terms of biofilm formation which correlated with structural features of genes for MSHA pili (msh), matrix polysaccharides (vps) and proteins (rbm) as well as for certain regulatory factors. Strains with none or few genetic deviations from prototypes formed mature biofilms in 5-7 days while those containing truncated genes mshL, mshN, rbmC – only in 13 days. One strain with truncated gene for positive regulator vpsR formed an immature biofilm. Acceleration of the process in some strains up to 2-3 days correlated with either truncated gene hapR (negative regulator) or altered structure of both msh and vps-rbm gene clusters.

Conclusion. Analysis of genetic determinants responsible for biofilm formation may be used for prediction of V. cholerae ability to survive in environmental objects of Russia and thus the potential danger of the latters as sources of infection.

Ecological genetics. 2018;16(4):23-32
Diversity of flax morphological characters in VIR genetic collection as a result of crop domestication
Porokhovinova E.A., Kutuzova S.N., Pavlov A.V., Buzovkina I.S., Brutch N.B.

Background. Almost all described flax (Linum usitatissimum L.) biodiversity is presented in VIR genetic collection(GC).

Materials and methods. 316 lines from GC belonging to 5 subspecies (indo-abyssinicum, hindustanicum, eurasiaticum, mediterraneum, transitorium) were characterized by morphological traits (MT), for some of them Mendel’s genetic control was evaluated.

Results. MT groups, genotypes typical for each of subspecies are revealed, but appearance of other phenotypes cannot be excluded, because subspecies can differ only in frequency of their occurrence. The genetic analysis was carried out. It expanded the list of MT genes. It was shown that many lines have similar mutations of MT regardless of their origin. Many MT genes are promising or already use in breeding for example YSED1 and ysed (yellow seed), pf-ad (pink flower, yellow seeds), dlb3 (pale blue flower), sfbs1 (white deformed flower). Soon lines carrier s1 gene (anthocyanin biosynthesis inhibitor), will be used because mucilage from seeds s1s1 has special polysaccharide compound and with wf1 (white flower) gene which is linked with early flowering. The linkage between the genes controlling dark blue flower (sfc6, sfc10) and yellow seeds (ysed2) was found, which must be taken into account while breeding for yellow seed.

Conclusion. The old landraces of GC can serve as source for any direction of breeding.

Ecological genetics. 2018;16(4):33-50
Specificity of the symbiotic interaction of bacteria of the genus Rhizobium leguminosarum bv. viciae with plants of the tribe Vicieae
Khapchaeva S.A., Didovich S.V., Topunov A.F., Mulyukin A.L., Zotov V.S.

The estimation of nodulation competitiveness of industrial strains against the native nodule bacteria and also the analyses of distribution of strain’s genotypes which formed nodules on roots of 4 plant species was the purpose of this work. The objects of the research were rhizobium strains which formed nodules on roots of plant (the nodule-forming units – NFU), obtained in field experiment with application of preseeding processing of seeds of pea (Pisum satіvum L.), fava beans (Vicia faba L.), lathyrus (Lathyrus sativus L.) and lentil (Lens culinaris L.). The mixture of the collection strains allocated from nodules of peas and beans, and having various combinations of chromosomal and symbiotic genotypes was used for inoculation of seeds. Identification of NFU was carried out with the use of the analysis of the emitted nodule total DNA on several chromosomal markers: the rpoB gene and the hin-region, and the plasmid marker – nodD gene. It is established that only about 50% of nodules were formed by the strains used at inoculation of seeds. Besides, the combinations of chromosomal and symbiotic genotypes specific for a rhizobium – symbionts of concrete host plants have been established: IA genotype with sym-2 for P. sativum; IB genotype with sym-4 for V. faba. The results of this study create prerequisites for selection of couples: macro- and microsymbiont for the purpose of increasing efficiency of plant-microbial systems, in which the nature of symbiotic interaction defines efficiency of partners.

Ecological genetics. 2018;16(4):51-60
Medicago lupulina lines with defects in the development of efficient arbuscular mycorrhiza
Yurkov A.P., Jacobi L.M.

Background. The work is aimed to solve actual problems in biology of arbuscular mycorrhiza (AM). Currently, a lot of mutants had been obtained in various plant model objects with defects in genes controlling AM development, however, the mechanisms controlling development of effective AM symbiosis are still unclear.

Materials and methods. The authors conducted a mutagenesis in Medicago lupulina, a new convenient model plant for molecular-genetic studies. High mycotrophic M. lupulina line have early and high response to mycorrhization, high seed production, as well as signs of dwarfism under conditions without of AM and low level of phosphorus available for plants. This method allows visually to identify plant lines with defects in AM symbiosis.

Results. 14 modes for mutagenesis by ethylmethanesulfonate were conducted. Usage of 3 mutagenesis modes allowed to obtain: productive M1 progeny with high part of viable seedlings (73.3%–86.0%); 1405 plants in M2 progeny.

Conclusion. According to population analysis for mutant plants in M2 progeny (up to M9 generation) 15 plant lines were selected: one Myc– plant line unable to form AM symbiosis, 4 Pen– plant lines unable to form AM symbiosis, but characterized by appressoria formation; 3 Rmd– plant lines forming low-activity ineffective AM symbiosis; 3 Rmd– plant lines forming low-activity effective AM and 4 Rmd++ plant lines forming effective AM with high abundance of symbiotic structures (mycelium/arbuscules/vesicles) in the roots.

Ecological genetics. 2018;16(4):61-74
Genetic toxicology
Comparative analysis of the expression of stress-related genes in two pea genotypes contrasting in tolerance to cadmium
Kulaeva O.A., Gribchenko E.S., Zorin E.A., Kliukova M.S., Zhukov V.A.

Background. A major problem of the environmental pollution with heavy metals, including cadmium, requires an intensive study of the molecular and genetic mechanisms underlying the tolerance of plants to these toxic substances. In this study we present a comparative analysis of the expression of stress-related genes in two pea genotypes contrasting in tolerance to cadmium.

Materials and methods. A unique mutant of pea SGECdt, characterized by the increased tolerance to cadmium, and initial line SGE were used. Gene expression was analyzed by Real Time PCR. Results. In the line SGE cadmium increase the expression of genes, encoding catalase, chitinase, chitinase-like protein PRP4A and dirigent protein PI206. In the mutant SGECdt cadmium increase the expression of genes, encoding chitinase, glutathione reductase and defensin DRR230. In control samples expression of genes encoding PRP4A and DRRR230 was enhanced in mutant SGECdt versus line SGE.

Conclusion. It was shown that, the reaction of the mutant SGECdt at the molecular level differs from that of the line SGE. In the mutant SGECdt, a change in the expression of a number of genes is observed, which may indicate that cadmium entering the cell causes activation of defense reactions.

Ecological genetics. 2018;16(4):75-84
Influence of γ-irradiation on the expression of encoding ABA metabolism enzymes in barley embryos
Bitarishvili S.V., Bondarenko V.S., Geras’kin S.A.

Background. Small doses of radiation stimulate the growth and development of plants including seed germination. ABA plays a key role not only in seed dormancy and germination but also in the regulation of adaptive reactions of plants.

The aim of our work was to study the effect of γ-irradiation of barley seeds in a small doses on the expression of genes encoding ABA biosynthesis enzyme 9-cis-epoxycarotenoid dioxygenase (HvNCED1) and catabolism enzyme ABA 8’-hydroxylase (HvABA8’OH-1).

Materials and Methods. The barley seeds were irradiated at dose range of 4–50 Gy at a dose rate of 60 Gy/h, the radiation source was 60Co. The study was carried out in the embryos within the first 30 hours after germination. Relative gene expression was investigated using real-time PCR (RT-PCR).

Results. It was shown that γ-irradiation of barley seeds changes the expression of ABA biosynthesis and catabolism genes in all experimental groups.

Conclusion. This alterations can lead to a decrease the ABA content under irradiation with stimulating doses and increase the biosynthesis of phytohormone under irradiation with inhibitory dose.

Ecological genetics. 2018;16(4):85-89

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