[Genes Associated with Increased Stress Sensitivity in Hypertensive ISIAH Rats].

Inherited stress-induced arterial hypertension (ISIAH) rats are characterized by increased stress reactivity of the hypothalamic-pituitary-adrenal and sympathoadrenal systems. The genetic basis of increased susceptibility to stress was studied in hypertensive ISIAH rats. Adrenal transcriptomes were sequenced in hypertensive ISIAH and normotensive WAG rats, and nine differentially expressed genes (DEGs) were found in the X-chromosome locus that was previously associated with mild emotional stress-induced increases in blood pressure and plasma corticosterone and an increased adrenal weight in ISIAH rats. An analysis of the functions performed by DEG-encoded proteins suggested the Sms (spermine synthase) gene to be the most likely candidate gene in the X-chromosome locus associated with an elevated stress susceptibility in ISIAH rats.

Allelic diversity of the Vrn genes and the control of growth habit and earliness in wheat.

Wheat is one of three main food crops around the world, which has the largest distribution area due to its adaptation to the different environments. This review considers polymorphisms and allelic variation of the vernalization response genes Vrn controlling the major adaptation traits in wheats (the genus Triticum L.): growth habit (spring vs. winter) and length of vegetative period (earliness). The review summarizes available information on the allelic diversity of the Vrn genes and discusses molecular-level relationships between Vrn polymorphisms and their effect on growth habit (spring vs. winter) and earliness (length vegetative period in spring plants) in di-, tetra- and hexaploid wheat species. A unique attempt has been made to relate information on mutations (polymorphisms) in dominant Vrn alleles to the values of the commercially most important trait "length of plant vegetative period (earliness)". The effects of mutations (polymorphisms) in the recessive vrn genes on vernalization requirement in winter wheats are considered, and this trait was formalized. The evolution of the winter/spring growth habit in the genus Triticum species is discussed. A scheme of phylogenetic interactions between Vrn alleles was constructed on the basis of these polymorphisms; the paper considers the possibilities to enhance the diversity of polymorphisms for the dominant Vrn genes and their alleles using wheat related species and rarely used alleles and discusses the prospects of breeding for improved earliness for concrete agroecological zones.

Earliness and morphotypes of common wheat cultivars of Western and Eastern Siberia.

The global and local climate changes determine the producing of highly-adaptive common (bread) wheat commercial cultivars of a new generation whose optimal earliness matches the climatic features of the territory where the cultivars are farmed. Principal component analysis involving our own and published data has been applied to investigate 98 commercial common wheat cultivars from Western and Eastern Siberia comparing their morphotypes; cultivar zoning time; length of the vegetation period; 1000-grain weight, and inheritance of spring growth habit. It demonstrated that the dominant Vrn gene polymorphism determining the spring growth habit of the Siberian cultivars was minimally polymorphic. In 75 % of the tested cultivars, the spring growth habit was controlled by digenic, namely dominant Vrn-A1 and Vrn-B1 genes. In 25 % of them (24 cultivars), spring growth habit is controlled by a single gene. In 19 and 5 of these cultivars spring growth habit is controlled by only one dominant gene, Vrn-B1 or Vrn-A1, respectively. In cv. Tulun 15, a trigenic control was identified. A conclusion about the optimality of the digenic control for the climatic conditions of both Western and Eastern Siberia has been confirmed. However, since none of the tested cultivars had the dominant Vrn-D1 gene typical of the regions of China and Central Asia bordering Siberia, it can be considered as an additional argument in favor of the European origin of Siberian common wheat cultivars. The revealed high frequency of the Vrn-B1c allele in the Western Siberian cultivars and the Vrn-B1a allele in the Eastern Siberian cultivars suggests their selectivity. The analysis also confirmed the dominance of red glume (ferrugineum, milturum) and awned spike (ferrugineum, erythrospermum) varieties in the Eastern Siberian cultivars, and white glume and awnedless spike (lutescens and albidum) ones in the Western Siberian cultivars. Small grain size cultivars are more typical of Eastern than Western Siberia. The retrospective analysis based on the cultivars' zoning time included in the "State Register for Selection Achievements Admitted for Usage" brought us to the conclusion that the earliness/lateness of modern Siberian commercial cultivars was not regionally but rather zonally-associated (taiga, subtaiga, forest-steppe and steppe zones).

[Expression of Catechol-O-Methyltransferase (Comt), Mineralocorticoid Receptor (Mlr), and Epithelial Sodium Channel (ENaC) Genes in Kidneys of Hypertensive ISIAH Rats at Rest and during Response to Stress].

Emotional stress plays a significant role in the processes of the development of arterial hypertension, especially in the presence of genetic predisposition. The origin and maintenance of hypertensive status during stress development can be activated by the sympathetic nervous system. An increase in sympathetic stimulation can, in turn, result in a change in the functions of kidneys, which provide fluid and electrolyte balance of the organism. A comparative study of the mRNA expression level of catechol-o-methyltransferase (Comt), mineralocorticoid receptor (Mlr), and ß-subunit of epithelial sodium channel (ß-ENaC) genes was conducted on the kidneys of hypertensive ISIAH rats and normotensive WAG rats at rest and after the effect of emotional stress. The discovered changes in the expression level of the selected genes confirm their involvement in increased sympathetic stimulation of the kidney, along with changes in the function of kidney regulation of fluid and electrolyte balance, which is an important factor of the development of sustained hypertension in the ISIAH rats strain.

[Differentially expressed genes in the locus associated with relative kidney weight and resting blood pressure in hypertensive rats of the ISIAH strain].

The comparative full-genome sequencing of transcriptomes of the renal cortex and medulla from hypertensive ISIAH rats and normotensive WAG rats revealed the differential expression of genes in the locus of chromosome 11 associated to the traits of resting blood pressure and relative kidney weight. Six differentially expressed genes (Kcne1, Rcan1, Mx1, Mx2, Tmprss2, and RGD1559516) were identified in the renal cortex, and three genes (Rcan1, Mx2, and Tmprss2) were identified in the renal medulla. An analysis of the functions of these genes pointed at the Rcan1 gene as the most relevant candidate gene associated with both the traits of resting blood pressure and relative kidney weight in ISIAH rats. The elevation of the transcription levels of the Mx1 and Mx2 genes in hypertensive ISIAH rats may represent an adaptation that contributes to the alleviation of inflammatory processes in the kidneys.

[Genetic loci for spleen weight and blood pressure in Isiah rats with inherited stress-induced arterial hypertension].

Recently, the important role of the spleen function in hypertension development was demonstrated. In this study, the genetic control of absolute and relative spleen weight was investigated to reveal the genetic loci common for spleen traits and for arterial blood pressure at rest and under the emotional stress conditions in the ISIAH rats with inherited stress-induced arterial hypertension. The search for genetic loci for absolute and relative spleen weight was performed on 6-month old F2 (ISIAH x WAG) hybrid males derived from a cross of hypertensive ISIAH and normotensive WAG rats. One significant QTL mapped on chromosome 1 and 5 suggestive loci were found for relative spleen weight. Four suggestive loci were detected for absolute spleen weight. All detected loci were novel. The significant QTL on chromosome 1 was common for relative spleen weight and arterial blood pressure at rest and under the emotional stress conditions in ISIAH rats. The results suggest that the manifestation ofthe stress-sensitive arterial hypertension in ISIAH rats may be related to the changes in genetic control of the spleen function.

Norepinephrine content in the hypothalamus and medulla oblongata of ISIAH rats is regulated by several genetic loci.

Five genetic loci regulating epinephrine content in rat hypothalamus and two loci in the medulla oblongata were identified using polymorphic microsatellite DNA markers. Allele polymorphism of these loci determines the differences between norepinephrine levels in brain compartments of hypertensive ISIAH and normotensive WAG rats. The interactions between the detected epinephrine-regulating loci are additive.

The characteristics of motor activity in ISIAH rats in an open field test are controlled by genes on chromosomes 2 and 16.

Quantitative Trait Locus (QTL) analysis was used to identify the loci of polygenic characteristics in a study of the genetic determination of the behavior of rats with inherited stress-induced arterial hypertension (ISIAH rats). Analysis was performed using males of two populations of F2 hybrids (ISIAH x WAG) of different ages: 3-4 (n = 106) and six months (n = 130). Chromosomes 2 and 16 in the young population of F2 rats showed significant associations between two characteristics of behavior in ISIAH rats and genetic loci: a) the rats' motor activity at the periphery of the open field area with loci in the regions of markers D2Rat157-D2Rat88 (LOD score 4.83; p = 0.000058) and D16Rat32 (LOD score 3.71; p = 0.00023). Together, these two loci accounted for 42.9% of the trait variability; b) the rats' motor activity during the first minute of the open field test and loci in the region of the marker D16Rat58 (LOD score 3.78; p = 0.00028). Results obtained by QTL analysis demonstrated a relationship between the genetic control of these traits and the animals' age.