Olga G. Koren

Panax ginseng natural populations: their past, current state and perspectives.

AbstractAim:The mating system of Panax ginseng, genetics and ontogenetic structure of its natural populations of Primorye (Russia) were investigated.Methods:Genetic diversity was assessed using allozyme and the fluorescently based automated amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR) markers.Results:Total genetic diversity at species level is low with allozyme assay (0.023), and high with AFLP (0.255) and SSR (0.259) methods. It is observed within populations according to allozyme (>99%), AFLP (>85%), and SSR (>73%) assays. The indices of genetic variability distribution point out the re-colonization of the Sikhote-Alin by ginseng plants from southern refuges during the warming period in the early Holocene. The capability of ginseng plants to cross- and self-pollinate was shown and the assumption that Panax ginseng is a facultative apomictic plant was confirmed. The reproductive system of ginseng possesses high plasticity and stability of the fertilization process that help the species to survive in stress conditions. Disturbances caused by external or internal factors can be reduced due to the morphogenetic potential of ginseng ovule or apomictic embryo development. Analysis of life stages structure of ginseng populations demonstrates that all of them are not full-constituents because some life stages are absent or occur rarely.Conclusion:In all 3 populations, virgin and young generative individuals are predominant. This means that populations studied are viable and the reintroduction of natural ginseng population is possible yet.

INHERITANCE AND VARIATION OF ALLOZYMES IN PANAX GINSENG C.A. MEYER (ARALIACEAE)

Three natural populations of Panax ginseng C.A. Meyer are known at present, and all of them are located in Russia’s Maritime Provinces. Allozyme analysis of 109 ginseng plants was used to evaluate the genetic variability in natural populations of this species. Three enzyme loci were polymorphic among 39 loci studied, and the mode of inheritance of these enzymes was verified by subsequent inheritance analysis of progeny from controlled crosses. All alleles were found in each population, and differences in allele frequencies were not significant. The level of variation was low for all of the populations studied, although genetic variability is still retained in Russia’s P. ginseng populations. The mean proportion of polymorphic loci for all of the populations was 0.076, with the mean number of alleles per locus 1.076. The mean expected heterozygosity and the mean observed heterozygosity were 0.024 and 0.023, respectively. We suggest that the low level of genetic variability of P. ginseng may reflect the evolutionary history of this species, such as a genetic bottleneck and/or the founder effect. Additionally, small current population sizes and intensive long‐term exploitation of the species may have also contributed to the low genetic diversity of P. ginseng.

Characterization of gene pools of three Pinus pumila (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 (P95 = 68.8%, Ho = 0.247, He = 0.291). Populations heterogeneity and significantly high level of divergence in coniferous (FST = 0.050, DN = 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.

Ginseng Conservation Program in Russian Primorye:Genetic Structure of Wild and Cultivated Populations

The Regional complex long-term program of restoration (reintroduction) of Primoryes ginseng population up to 2005 elaborated by Primorye governor administration, Regional Committee of Natural Resources and Russian Academy of Sciences operates in Russian Primorye. The Institute of Biology and Soil Science (IBSS) provides the scientific implementation of the program including the genetic analysis of extant ginseng populations, plant reproduction and offspring identification. According to our investigations, the genetic resource of P. ginseng in Primorye is represented by three populations of wild-growing ginseng and a few private plantations. The results obtained by RAPD allowed concluding that the resource is dispersed among the wild and cultivated ginseng sub-populations in such a way that each of sub-populations studied has to be represented as a stock material to maintain species genetic variability. The allozyme analyses also showed that the small sub-populations of wild ginseng are characterized by unique genetic diversity and, therefore. they all need to be represented in reintroduction centers. Additionally the allozyme analysis discovered that the Blue Mountain and Khasan populations possess the most genetic diversity. So, at least one more reproductive ginseng unit has to be created besides two already existing reintroduction centers representing the Sikhote-Alin and the Blue Mountain populations.

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 (Ho 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.

Living on the Edge: Various Modes of Persistence at the Range Margins of Some Far Eastern Species

Present-day patterns of plant distribution have been formed under the influence of various biotic and abiotic factors. Plant distribution reflects the habitat preferences of species and the outcome of their competition as well as the complex evolutionary processes resulting in the specificity of mating systems, the genetic structure of different species and other aspects of species biology. Together, these factors determine the current ranges and distributions of plant species. At the edge of a species range, the significance of particular interactions with the environment becomes more pronounced. However, our understanding of this class of interactions is limited. There is debate about whether these interactions represent a distinct and ordered set of related phenomena or whether they are unrelated and without order. Different approaches to this problem are needed in different situations. Understanding the processes of microevolution in species at the edges of their ranges is of great interest, particularly in view of the continuing decline in worldwide biodiversity and ongoing and future climate changes. When the area of a plants habitat is sufficient, most populations exist in a relatively stable condition, and changes in their genetic structure follow slow processes, such as gene flow and genetic drift. However, in populations growing at the edge of their range, the rates of genetic processes can change dramatically. At the limits of the climatic and ecological tolerance of species, populations usually become smaller and more fragmented. These populations are generally less genetically diverse than those living at the center of the range because they exist in less favorable habitats and at lower densities, and consequently, they may be more prone to extirpation (Hampe & Petit, 2005; Vucetich & Waite, 2003). However, some species may have existed as groups of isolated populations for thousands of generations. The long-term survival and evolution of a species depends on the maintenance of sufficient genetic variability within and among populations. Patterns of population genetic diversity have been shown to be generally shaped by past climate-driven range dynamics, rather than solely by stochastic demographic and genetic processes (Hewitt, 2004). Given the enormous variety of plant life forms and their habitats as well as the complexity of their evolutionary histories, it is difficult to accept as a general rule that all marginal populations will exhibit lower genetic diversity than those from the center of a

Genetic variation of the relict species Acanthopanax sessiliflorus (Rupr. et Maxim.) Seem. (Araliaceae) in Primorsky Krai

Based on the analysis of 17 genes encoding the allozyme diversity of 12 enzyme systems, data were obtained on the genetic variation of a relict of the Tertiary flora, a valuable medicinal plant Acanthopanax sessiliflorus (Rupr. et Maxim.) Seem. (Araliaceae) in the Russian area of its range. Indices of polymorphism for populations had rather high values on average (P95 = 42.4%, A = 1.55, Ho = 0.211, and He = 0.168), which are comparable with the known data for populations of A. sessiliflorus from the peninsula of Korea. The level of genetic diversity and its distribution among populations reflects the interaction of several factors, among which the most important are the historical past of the species, genetic drift, and the plasticity of the reproduction system. The obtained data can serve as a basis for the conservation of genetic resources of Far Eastern Araliaceae species.

Emerging Roles of Agrobacterial Plant‐Transforming Oncogenes in Plant Defense Reactions

For recent years, engineering plant metabolic pathways by using rol genes looks promising in several aspects. New directions of rol‐gene studies are highlighted in this work underlying the unique regulatory properties of the genes. It is known that following agrobacterial infection, the Agrobacterium rhizogenes rolA, rolB and rolC genes are transferred to plant genome, causing tumor formation and hairy root disease. In this report, we show mat these oncogenes are also involved in regulation of plant defense reactions, including the production of secondary metabolites. Situations occur where the rol genes perform their own critical function to regulate secondary metabolism by bypassing upstream plant control mechanisms and directing defense reactions via a “short cut.” The rolC gene expressed in transformed plant cells is efficient in establishing an enhanced resistance of host cells to salt and temperature stresses. The emerging complexity of the rol‐gene triggered effects and the involvement of signals generated by these genes in basic processes of cell biology such as calcium and ROS signaling indicate that the plant oncogenes, like some animal protooncogenes, use sophisticated strategies to affect cell growth and differentiation. The data raise the intriguing possibility that some components of plant and animal oncogene signaling pathways share common features.For recent years, engineering plant metabolic pathways by using rol genes looks promising in several aspects. New directions of rol‐gene studies are highlighted in this work underlying the unique regulatory properties of the genes. It is known that following agrobacterial infection, the Agrobacterium rhizogenes rolA, rolB and rolC genes are transferred to plant genome, causing tumor formation and hairy root disease. In this report, we show mat these oncogenes are also involved in regulation of plant defense reactions, including the production of secondary metabolites. Situations occur where the rol genes perform their own critical function to regulate secondary metabolism by bypassing upstream plant control mechanisms and directing defense reactions via a “short cut.” The rolC gene expressed in transformed plant cells is efficient in establishing an enhanced resistance of host cells to salt and temperature stresses. The emerging complexity of the rol‐gene triggered effects and the involvement of signals g...