Divergence of Oxytropis Species from the Section Verticillares (Fabaceae) of Steppe Flora of Baikal Siberia Based on Analysis of Chloroplast DNA

Russian Journal of Genetics - The analysis of nucleotide sequence polymorphism of chloroplast DNA psbA–trnH, trnL–trnF, and trnS–trnG intergenic spacers in the Oxytropis lanata,...     

Characterization of gene pools of three <Emphasis Type="Italic">Pinus pumila</Emphasis> (Pall.) Regel populations at the range margins

Genetic variation of Siberian dwarf pine Pinus pumila (Pall.) Regel was characterized in three marginal populations in southwestern, southern and eastern parts of the natural species range (Baikal Area, Primorye, Kamchatka) using isozyme analysis. Analysis involving 16 isozyme loci encoding ten enzyme systems was conducted. Our results confirm that P. pumila is one of the most polymorphic species in the genus Pinus. Three marginal populations exhibited high genetic variation (P ₉₅ = 68.8%, H _o = 0.247, H _e = 0.291). Populations heterogeneity and significantly high level of divergence in coniferous (F _ST = 0.050, D _N = 0.044) reflect their genetic originality. In summary, it was shown that the level of genetic variation characteristic for P. pumila in other parts of the not only is reproduced in the populations examined but even is close to maximum there.     

High level of polymorphism and autotetraploid origin of rare endemic species of Fabaceae, Oxytropis chankaensis Jurtz., inferred from allozyme data

Using starch electrophoresis, we examined 19 enzyme systems presumably controlled by 35 loci in the rare endemic tetraploid species Oxytropis chankaensis Jurtz. (Fabaceae). Electrophoretic patterns and their genetic interpretation are presented. The isozyme data suggest tetrasomic inheritance in O. chankaensis. Three or four alleles at a particular locus were found in a number of individual plants, which indicate the autotetraploid origin of this species. Seventeen loci were shown to be polymorphic. As reliable gene markers for population systems, we recommend highly active polymorphic systems showing good allozyme separation (Ce-2, Gpi-2, Gpt-2, Idh-2, Lap, Mdh-2, and Mdh-3). Parameters of allozyme variability proved to be very high for a rare species with a restricted range: P = 48.6%, Ap = 3.06, Hob = 0.173.     

Analysis of Genetic Variation in Rare Endemic Species Oxytropis chankaensis Jurtz. (Fabaceae) Using RAPD Markers

The method of polymerase chain reaction with random primers (RAPD) was used to assess genetic variation and population differentiation in the rare endemic plant Oxytropis chankaensis Jurtz. (Fabaceae). DNA samples from plants of two isolated populations were compared at 133 loci detected by use of ten primers. Both populations examined were characterized by high polymorphism levels (P ₉₅ = 72.9%; A = 1.92 and P ₉₅ = 74.4%; A = 1.88, respectively). They were also statistically significantly different in the frequencies of most of the amplicons. For each of the plants, unique multilocus RAPD phenotype was established using 17 to 20 RAPD markers. Diagnostic markers were not revealed. The populations were poorly differentiated. On average, the between-population component accounted for about 8% of the variation, while 92% of the variation was detected within populations. High variation along with the low degree of differentiation characteristic of two most geographically remote populations of O. chankaensis can have several explanations, among which a polyploid origin of the species seems to be most important.     

High chloroplast haplotype diversity in the endemic legume <Emphasis Type="Italic">Oxytropis chankaensis</Emphasis> may result from independent polyploidization events

Oxytropis chankaensis Jurtz. (Fabaceae) is an endangered perennial tetraploid species endemic to the Khanka Lake coast. In Russia, O. chankaensis is distributed across a very restricted zone along the western shore of this lake. To characterise all known populations of this species, we assessed the genetic diversity of four noncoding regions of chloroplast DNA (cpDNA). Variable sites detected within the trnL–trnF, the petG–trnP, and the trnS–trnG regions allowed the identification of seven haplotypes. On the other hand, no variation was found in the trnH–psbA region. O. chankaensis exhibited an overall low level of nucleotide diversity (π = 0.00052) but a marked haplotype diversity (h = 0.718). A combination of three or four haplotypes was found in each population, and most of the cpDNA variation (above 90%) was distributed within populations. The level of genetic structure that we detected in O. chankaensis using maternal plastid DNA markers was much lower (G _ST = 0.037) than the average that is estimated for angiosperms. We found no evidence for isolation by distance or for phylogeographic structuring in O. chankaensis. Our data suggest that autopolyploidy has arisen more than once in the evolutionary history of this species. Repetitive expansion and contraction during past and ongoing demographic events both seem to be involved in shaping the current genetic structure of O. chankaensis. This study provides valuable information for developing the most appropriate strategy for conserving this endemic species with a narrow habitat range.     

Genetic variation in six species of the genus Oxytropis DC. (Fabaceae) from Kamchatka Peninsula

Using the isozyme analysis, genetic variations in six species of the genus Oxytropis DC. (Fabaceae) from Kamchatka was assessed. It was demonstrated that diploid species from the section Arctobia were characterized by a low level of variations typical of endemic plant species. At the same time, polyploid species from the Orobia section demonstrated very high values of the heterozygosity parameters (H _o varied from 0.200 to 0.274). It has been suggested that the level of polymorphism of the oxytropes from Kamchatka was shaped as a result of the interaction of a number of factors, among which the most important are the ecological confinedness of the species, the specific features of the reproductive system, and gene drift. In the species of Orobia section, it is also the presence of the polyploid genome.     

The effect of some antiseptic drugs on the energy transfer in chromatophore photosynthetic membranes of purple non-sulfur bacteria Rhodobacter sphaeroides

Photosynthesis Research - Chromatophores of purple non-sulfur bacteria (PNSB) are invaginations of the cytoplasmic membrane that contain a relatively simple system of light-harvesting...     

Modern State of Populations of Endemic <Emphasis Type="Italic">Oxytropis</Emphasis> Species from Baikal Siberia and Their Phylogenetic Relationships Based on Chloroplast DNA Markers

The genetic diversity and population structure of the endemic species of Baikal Siberia Oxytropis triphylla, O. bargusinensis, and O. interposita were studied for the first time on the basis of the nucleotide polymorphism of intergenic spacers psbA–trnH, trnL–trnF, and trnS–trnG of chloroplast DNA. All populations of these species were characterized by a high haplotype (0.762–0.924) and relatively low nucleotide (0.0011–0.0022) diversity. Analysis of the distribution of variability in O. triphylla and O. bargusinensis showed that there was no significant genetic differentiation between populations of each species; the gene flow was 4.43 and 8.91, respectively. The high level of genetic diversity in the studied populations indicates a relatively stable state of these populations. A study of the phylogenetic relationships of closely related species confirms the concept of the origin of O. bargusinensis and O. tompudae as a result of intersectional hybridization of the species of the sections Orobia and Verticillares.     

Conserving the gene pool of Far Eastern plants by means of seed cryopreservation

Cryotolerance of seeds has been studied in 103 plant species of 33 families from five regions of the Russian Far East. In 89.1% of these species, seed viability has not decreased in the course of cryogenic storage. Six species have shown interpopulation variation in the seed response to extremely low temperature (?196°C). Freezing in liquid nitrogen, which results in deep anabiosis, can be used as a means for long-term seed storage. A preliminary assessment of genetic diversity at the population level provides for the maximum possible mobilization of the species gene pool. The results of this study contribute to the development of a scientific basis for creating a seed bank of the Far Eastern flora with the purpose to conserve and restore biological resources of the region.