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The effect of melafen, a plant growth regulator of a new generation, on the growth, pigment composition, and expression of nuclear genes Elip1 and Elip2 encoding chloroplast light-stress proteins in barley (Hordeum vulgare L) seedlings was studied. It is shown that the height of seedlings treated with melafen at concentrations of 0.5 x 10(-10) and 0.5 x 10(-8) M increased by approximately 10 and 20%, respectively, as compared to the control. At high concentrations (10(-5) and 10(-3) M), melafen had no effect on the growth of seedlings. The content of chlorophylls and carotenoids in chloroplasts barely differed from the control at all melafen concentrations tested. Reverse transcription-polymerase chain reaction (RT-PCR) showed that melafen did not influence the expression of the nuclear gene encoding the low-molecular-weight plastid stress protein ELIP1. At the same time, the expression of the nuclear gene encoding the high-molecular-weight light-inducible stress protein ELIP2 in the plants treated with melafen at a concentration of 0.5 x 10(-8) M, increased by approximately 70 %. At higher concentrations, melafen suppressed the Elip2 gene expression. Thus, melafen affects the expression of the Elip2 gene, which is involved in the regulation of chlorophyll synthesis and chloroplast biogenesis, which, in turn, may lead to changes in the resistance of plants to light-induced stress.

An inhibitor analysis was used for studying the tetrapyrrole role in the regulation of the expression of the nuclear gene encoding a low-molecular-weight protein, a stress plastid light-inducible protein ELIP. 2,2'-Dipyridyl and norflurazon were used as inhibitors. Experiments with dipyridyl demonstrated that tetrapyrroles were involved in the regulation of Elip gene expression, inhibiting it by approximately 50%. Similar results were obtained when there was photodestruction of the chloroplasts, caused by a plant treatment with norflurazon. The results confirm the involvement of the chloroplasts in the regulation of the nuclear gene expression coding for plastid proteins. Tetrapyrroles are important contributors to this process.

Three-dimensional models of FtsZ-protein complexes with GDP from Arabidopsis thaliana L. localized in cytosol (Entrez database code NP190843) and in chloroplasts (Entrez database code AAA82068) were developed. Crystal structure of the FtsZ-GDP complex from archaea Methanococcus jannaschii (PDB-code 1FSZ) was used as a matrix. Secondary structures of computed models contain ten beta-strands. A chloroplast form of FtsZ-protein has ten alpha-helices and four 3(10)-helices, whereas cytosolic form of protein has nine and three structures correspondently and neither a0-helix before nucleotide-binding domain nor C-terminal 3(10)-helix in secondary domain. The T2-loop of nucleotide-binding pocket of chloroplast form of FtsZ-ptotein in position 111 contains non-charged alanin residue instead of the charged one which is typical for cytosolic and bacterial forms of proteins. At low sequence homology of FtsZ-proteins (approximately 47%) the developed models demonstrate high coincidence with matrix both in the structures of nucleotide-binding pocket and in the whole molecule. The models are completely suitable for further studies of possible sites of binding with dinitroaniline herbicides.

In this report we present phylogenetic tree based on the sequences of FtsZ-proteins of Archaea, Bacteria and Eukaryota. We have analyzed the relative positions of separate sequences and their clusters and their distance to the hypothetical root of phylogenetic tree as well. It has been demonstrated that most of procaryotic and eucaryotic FtsZ-protein sequences are located at the distance of 0.3-0.8 substitutions per site from the hypothetical root of phylogenetic tree. The tubulins are outlined from the root at 7-8 fold larger distances in comparison with the separate sequences. This confirms the slight aminoacid homology between these two groups of cytoskeletal proteins. At the same time the significant similarity between FtsZ-proteins of cyanobacteria and of plant plastids has been shown.

Morphological analysis of flowers was carried out in Arabidopsis thaliana wild type plants and agamous and apetala2 mutants. No direct substitution of organs takes place in the mutants, since the number and position of organs in them do not correspond to the structure of wild type flower. In order to explain these data, a notion of spatial pattern formation in the meristem was introduced, which preceded the processes of appearance of organ primordia and formation of organs. Zones of acropetal and basipetal spatial pattern formation in the flower of wild type plants were postulated. It was shown that the acropetal spatial pattern formation alone took place in agamous mutants and basipetal spatial pattern formation alone, in apetala2 mutants. Different variants of flower structure are interpreted as a result of changes in the volume of meristem (space) and order of spatial pattern formation (time).

Expression of Mdh1 alleles has been studied in 60 apozygotic (agamospermic) sugar beet progenies. Seed progenies were obtained by uniparental (pollen less) mode of seed reproduction: selfing of pollen-sterile plants isolated with paper bags. The apozygotic seed progenies demonstrate a disomic gamete autosegregation, i.e., the ratio between genotypes in the progenies correspond to the gamete segregation in a duplex heterozygote of an autotetraploid. It was shown that the ratio between the Mdh1 phenotypes in apozygotic progenies is strongly affected by spontaneous inactivation of one of the alleles. In most progenies, the excess of FF phenotypes and the deficit of SS phenotypes were observed. In our opinion, such deviations in genotype and phenotype frequencies result from conversion of the active Mdh1-S into the inactive Mdh1-S0 allele (epigenetic gene inactivation). The spontaneous inactivation of one allele results in extremely variable frequencies of heterozygous Mdh1-F/Mdh1-S genotypes and phenotypes in the apozygotic seed progenies. The empirical distribution of the frequencies of heterozygous genotypes in the apozygotic seed progenies is given by a negative binomial distribution describing the expected time of occurrence of random events.