Investigation of systemic control of plant cell division and differentiation in the model of tumor growth in radish

The study addresses the control of plant cell division and differentiation using the model of tumor-forming lines of radish. Expression of the genes involved in control of the cell cycle (CycD3), maintenance of meristematic cell activity (STM, WUS, and KNAT1), and primary response to cytokinin (ARR) was studied in inbred radish lines characterized by tumor growth at different stages of development. The influence of exogenic cytokinin on the expression of the genes of interest is analyzed. The possible role of the CycD3, KNAT1, STM, WUS, and ARR5 in tumor formation in radish is discussed.     

Genes regulating the development and functioning of the nervous system determine life span in <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

Earlier, it has been shown that genes responsible for differences in longevity between wild-type Drosophila melanogaster lines 2b and Oregon are localized in region 7A6-B2, 36E4-37B9, 37B9-D2, and 64C-65C. Quantitative complementation tests were conducted between the gene mutations localized in these regions and involved in catecholamine biosynthesis (iav (inactive), Catsup (Catecholamines up), amd (alpha metil dopa-resistant), Dox-A2 (Diphenol oxidase A2), ple (pale)) and neuron development control (Fas3 (Fasciclin 3), tup (tail up), Lim3), on the one hand, and two different normal alleles of these genes in lines 2b and Oregon, on the other. Complementation was found for genes iav, Fas3, amd, and ple. The remaining genes (Catsup, Dox-A2, tup, and Lim3) are candidate genes for controlling differences in longevity between lines 2b and Oregon.     

Identification and expression analysis of cytokinin response regulators in <Emphasis Type="Italic">Fragaria vesca</Emphasis>

Cytokinin response regulators (RRs) are important components of the two component signal systems, which are involved in the regulation of plant growth and development, and in the response to abiotic stress. In this study, 18 cytokinin RR genes were identified in Fragaria vesca through the genome-wide search. They were further classified into three types: type-A (FvRR1–7), type-B (FvRR8–14) and type-C (FvRR15–18) according to the domain architecture and the phylogeny. Phylogenetic analysis demonstrated that most cytokinin response regulators of F. vesca and Arabidopsis formed clear orthologous pairs. Expression patterns of the cytokinin FvRR genes in various tissues and organs at reproductive stages were detected in this study. Additionally, gene expression response patterns to ABA and abiotic stresses including high temperature and osmotic stress were investigated. The results showed that different types of cytokinin FvRRs have different expression patterns, suggesting the functional differentiation of cytokinin FvRRs during the evolution. This systematic study provides insights into possible functions of the cytokinin FvRR genes and a basis for further functional analysis.     

Genetic Control of the Wavy Shoots Character in Radish <Emphasis Type="Italic">Raphanus sativus</Emphasis> L.

The results of genetic analysis of the wavy shoots character supported the hypothesis on the existence of two genes, Wsh1 and Wsh2, whose mutations caused wavy shoots in radish lines 16 and 26, respectively. As shown by analysis of joint inheritance with marker characters, wavy shoots were inherited independently of the biochemical markers (genes Lap1, Ep, Dia1, and Aat). Gene Wsh1 was shown to be linked to genes A, ac, and ar; the mode of inheritance depended on the cross combination. In hybrids with mutant line 16, plants with novel morphological defects, which were absent in the parental forms, were detected. Possible mechanisms of new morphological abnormalities and change of linkage in the combinations analyzed are discussed.     

Role of CLE41 Peptide in the Development of Root Storage Parenchyma in Species of the Genus <Emphasis Type="Italic">Raphanus</Emphasis> L.

CLE peptides (CLAVATA3/ENDOSPERM SURROUNDING REGION) are signal molecules or plant peptide hormones that play an important role in regulation of development of various meristems governing the expression of WOX (WUSCHEL-RELATED HOMEOBOX) genes. In particular, CLE peptides belonging to a small TDIF (Tracheary Element Differentiation Inhibitory Factor) group are responsible for the operation of gene WOX4 controlling the development of cambium and the conducting system. We looked into the role of CLE41 peptide from the TDIF group in the development of storage root in two species of the genus Raphanus: cultivated radish (Raphanus sativus var. radicula Pers.) that is a popular root crop with a storage root and its ancestor wild radish (Raphanus raphanistrum L.) where storage parenchyma of the root is poorly developed. It was shown that overexpression of gene RsCLE41 and plant treatment with exogenous peptide CLE41 influenced the development of cambium and xylem in the roots of R. sativus and R. raphanistrum and affected expression of the genes from different groups. One could say that peptide CLE41 activates expression of the genes whose homologues in arabidopsis play a key role in the maintenance of cambium (RsWOX4, RsWOX14, RsHAM4, and RsCYCD3). In the storage root of radish, peptide CLE41 activates proliferation of cambium cells reducing the amount of one of the xylem’s elements (lignified parenchyma). The obtained results point to an important role of CLE41 in the development of storage root in radish.     

Participation of <Emphasis Type="Italic">SRM5/CDC28</Emphasis>, <Emphasis Type="Italic">SRM8/NET1</Emphasis>, and <Emphasis Type="Italic">SRM12/HFI1</Emphasis> genes in checkpoint control in yeast <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

About twenty genes participating in checkpoint control are known in yeast Saccharomyces cerevisiae. The involvement of SRM genes in the cell cycle arrest under the action of DNA damaging agents was studied in this work. These genes were earlier defined as genes affecting genetic stability and radiosensitivity. It was shown that mutations srm5/cdc28-srm, srm8/net1-srm, and srm12/hfi1-srm fail the cell cycle arrest in the presence of DNA damage and influence the checkpoint arrest in G0/S (srm5, srm8), G1/S (srm5, srm8, srm12), S (srm5, srm12), and G₂/M (srm5). It seems likely that genes SRM5/CDC28, SRM12/HFI1/ADA1, and SRM8/NET1 are involved in a cell response to DNA damage, and in checkpoint regulation in particular.     

Both epiphytic and endophytic strains of <Emphasis Type="Italic">Rhodococcus fascians</Emphasis> influence transporter gene expression and cytokinins in infected <Emphasis Type="Italic">Pisum sativum</Emphasis> L. seedlings

Some strains of the soil bacterium Rhodococcus fascians maintain an epiphytic life style while others become endophytic. Virulent, endophytic strains cause multiple shoot growth and inhibit root growth of seed-inoculated Pisum sativum L. We were interested in assessing, at the molecular level, the impact of strains of contrasting niche on the emerging shoots and roots of inoculated seeds. The presence of R. fascians was monitored microscopically, endogenous cytokinin and chlorophyll levels were measured, and the expression of genes monitored by RT-qPCR. The expression of the pea sugar transporter genes (SWEET and SUT), amino acid (AAP) transporters and cell wall invertase gene family members, as well as expression of plant and bacterial cytokinin biosynthesis (IPT), activation (LOG) and degradation (CKX) genes were monitored. Both the virulent strain and the epiphytic strain affected the expression of the transporter genes, with less obvious differences between the strains on the shoot compared with the effect on the root. Strong expression of the R. fascians genes, RfIPT, RfLOG and RfCKX, in pea seedlings at 15 days post inoculation was mirrored by increased expression of transporter gene family members in the plant. However, the elevated levels of isopentenyl adenine-type and zeatin-type cytokinins were not consistently associated with the virulent strain. In conclusion, while both the virulent strain and the epiphytic strain impacted the expression of transporter genes in the shoots and roots, only the virulent strain affected morphology. The inhibited root growth, the greening of the roots, and the expression of the pea response regulators in the infected roots are indicative of a response to cytokinin, but a role for the ‘classical’ cytokinins as virulence determinants was not established.     

Role of Gene-Gene Interactions in the Chromosomal Instability in Workers at Coal Thermal Power Plants

The 23 polymorphic variants in genes encoding the enzymes of xenobiotics biotransformation (CYP1A1 (rs4646903), CYP1A2 (rs762551), GSTP1 (rs1138272, rs1695), GSTM1 (del), and GSTT1 (del)), DNA repair (XRCC1 (rs25489, rs25487), APEX1 (rs1130409), hOGG1 (rs1052133), ADPRT (rs1136410), XPD (rs13181), XPG (rs17655), XPC (rs2228001), ATM (rs1801516), NBS (rs1805794), XRCC2 (rs3218536), and XRCC3 (rs861539)), antioxidant system (MnSOD (rs4880) and GPx1 (rs1050450)), cell cycle control and apoptosis (TP53 (rs1042522)), DNA methylation (MTHFR (rs1801133) and MTR (rs1805087)), and chromosomal aberrations in lymphocytes in the workers at thermal power plants were analyzed. We found that allelic variants in the CYP1A1 (rs4646903), hOGG1 (rs1052133), XRCC1 (rs25487), and APEX1 (rs1130409) genes were associated with an increased level of chromosomal aberrations in workers. Informative models of gene-gene interactions including CYP1A1 (rs4646903, T>C), CYP1A2 (rs762551, C>A), GSTT1 (del); XRCC1 (rs25487, G>A), MTHFR (rs1801133, C>T), GSTT1 (del); XRCC1 (rs25487, G>A), APEX1 (rs1130409, T>G), TP53 (rs1042522, G>C) determining the formation of the increased frequency of chromosomal aberrations in the workers at coal thermal power plants were discovered.     

Cell culture system versus adventitious root culture system in Asian and American ginseng: a collation

Panax ginseng and Panax quinquefolius of Panax genus are valuable as health foods as well as pharmaceuticals for the treatment of cancer, diabetes and ageing as these plants possess saponins. In the current study, Cell and adventitious root cultures of P. ginseng and P. quinquefolius were investigated for the biomass, cell division, saponin content and ginsenosides profile from four lines namely P. quinquefolius (AM), P. ginseng mountain (Mt.) Baekdu line, P. ginseng Cheong-sol line (CS) and P. ginseng CBN line (CBN) with the objective of comparing cell and adventitious root systems to check their efficacy for the production of ginseng saponins. Additionally, genes related to ginsenoside biosynthesis were also analyzed concerning to cell and adventitious root lines. The results indicated that various cell lines were better in multiplication and growth compared to adventitious root lines. However, adventitious root lines showed higher accumulation of dry biomass (1.5–2 fold) than that of cell lines. CS adventitious root line showed higher saponin content and ginsenoside productivity (10.48 mg·g^?1 DW, 12.88 mg·L^?1, respectively) than that of CS cell line (9.50 mg·g^?1 DW, 2.39 mg·L^?1, respectively). Especially, Rd ginsenoside productivity of CS adventitious root line recorded fourfold higher than CS cell line. Genes which are related to ginsenoside biosynthesis such as P. ginseng squalene synthase (PgSS2), P. ginseng squalene epoxidase (PgSE2), P. ginseng protopanaxadial synthase (PgPPDS) and P. ginseng protopanaxatriol synthase (PgPPTS) were analyzed by real time quantitative polymerase chain reaction to support ginsenoside production. The adventitious root culture system described in this study is useful system for biomass and ginsenoside production.     

Altered somatic mutation level and DNA repair gene expression in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> exposed to ultraviolet C,salt, and cadmium stresses

It is known that somatic mutations arising during animal growth and ageing contribute to the development of neurodegenerative and other animal diseases. For plants, several studies showed that small-scale somatic DNA mutations accumulated during Arabidopsis life cycle. However, there is a lack of data on the influence of environmental stresses on somatic DNA mutagenesis in plants. In this study, we analyzed the effects of ultraviolet C (UV-C) irradiation, high soil salinity, and cadmium (CdI₃) stresses on the level of small-scale somatic DNA mutations in Arabidopsis thaliana. The number of DNA mutations was examined in the Actin2 3′UTR (Actin-U1), ITS1-5.8rRNA-ITS2 (ITS), and ribulose-1,5-biphosphate carboxylase/oxygenase (rbcL) DNA regions. We found that somatic mutation levels considerably increased in CdI₃-treated Arabidopsis plants, while the mutation levels declined in the UV-C- and NaCl-treated A. thaliana. Cadmium is a mutagen that is known to inhibit DNA repair processes. The detected stress-induced alterations in somatic DNA mutation levels were accompanied by markedly increased expression of base excision repair genes (AtARP, AtDME, AtDML2, AtDML3, AtMBD4, AtROS, AtUNG, and AtZDP), nucleotide excision repair genes (AtDDB1a, AtRad4, and AtRad23a), mismatch repair genes (AtMSH2, AtMSH3, and AtMSH7), and photoreactivation genes (AtUVR2, AtUVR3). Thus, the results demonstrated that UV-C, high soil salinity, and cadmium stresses influence both the level of DNA mutations and expression of DNA repair genes. Salt- and UV-induced activation of DNA repair genes could contribute to the stress-induced decrease in somatic mutation level.