Genetic Diversity in Some Oxytropis Species in the

North-East Asia

A.B. Kholina, O.V. Nakonechnaya

Institute of Biology and Soil Science, FEB RAS, Vladivostok

Oxytropis is a large and diverse genus comprising about 300 species (Jurtzev, 1999), among them a lot of rare, endemic and valuable medicinal plants widely used in oriental medicine. On the Russian Far East Oxytropis species are representatives of the coastal and volcanic mountain floras. The risk of extinction of these species is very high because of both natural phenomena (volcanic eruptions, fires, fluctuations of sea level, storms, landslides, etc.) and anthropogenic impact (high recreational load and economic activity).

Oxytropis hidakamontana Miyabe et Tatew. Photo by V.Yu. Barkalov

To conserve genetic resources of these species, it is necessary to assess its genetic diversity. We explored allozyme variation in 8 Oxytropis species from North-East Asia.

Section ArctobiaO. kamtschatica Hult., endemic, 2n = 16.Kamchatka Peninsula, Central Kamchatka, Kljuchevskaia Sopka volcano. O. revoluta Ledeb., widespread, 2n = 16.population 1. Kamchatka Peninsula, Central Kamchatka, Tolbachik volcano. population 2. Kamchatka Peninsula, Central Kamchatka, Kljuchevskaia Sopka volcano.Section OrobiaO. calcareorum N.S. Pavlova, endemic, 2n = 32.Sakhalin Island, Eastern-Sakhalin Mts, Mt. Vaida. O. erecta Kom. endemic, 2n = 48.Kamchatka Peninsula, Southeastern Kamchatka, near Petropavlovsk-Kamchatskiy.O. hidakamontana Miyabe et Tatew., endemic, 2n = 16.Kuril Islands, Shikotan Island, Mt. Notoro. O. ochotensis Bunge, regional, 2n = 64.Kamchatka Peninsula, Central Kamchatka, Kljuchevskaia Sopka volcano. O. retusa Matsum, endemic.Kuril Islands, Paramushir Island, Shelehov Bay. Section BaicaliaO. chankaensis Jurtz., endemic, 2n = 32.Primorye, Khanka Lake, Sosnovyi Island.

Oxytropis retusa Matsum.

Photo by V.Yu. Barkalov

Oxytropis revoluta Ledeb.

Photo by S.K. Kholin

Chromosome number, geographic range and sampling site locations for Oxytropis species

IDH GPI GPI

MDH

CE

PGM LAP AAT

Electrophoretic patterns of some polymorphic loci of Oxytropis chankaensis

Electrophoretic analysis of the leaf tissue of Oxytropis plants was carried out using 25 enzyme systems (ADH, ALD, ACP, G-3PDH, G-2-DH, GPI, HK, IDH; FDP, GDH, 6-PGD, AAT, ACO, CE, FE, GPT, SKDH, LAP, MDH, MPI, SDH, FUM, AK, PGM, FDH).

Out of the enzyme systems studied for each species, we selected highly active polymorphic systems, which can be recommended as reliable gene markers.

Allozyme variation parameters in examined Oxytropis species

SpeciesStatus

2n NNumberof loci

P, % A AP HO

O. revoluta – 16 30 26 38.5 1.58 2.50 0.162

O. ochotensis – 64 32 21 61.9 2.05 2.69 0.265

O. retusaendemic,

rare–

19 21 14.3 1.19 2.33 0.068

O. hidakamontana endemic 16 13 21 14.3 1.19 2.33 0.076

O. kamtchaticaendemic,

rare 16 27 30 43.3 1.67 2.54 0.199

O. chankaensisendemic,

rare 32 294 28 42.9 2.00 3.33 0.266

O. calcareorum endemic 32 32 21 47.6 1.67 2.40 0.198

O. erecta endemic 48 16 27 44.4 1.56 2.42 0.250

Note. N – sample size; P - percentage of polymorphic loci; A, AP - mean number of alleles per locus and per polymorphic locus; HO - observed heterozygosity.

O. chankaensisendemic,

rare 32 294 28 42.9 2.00 3.33 0.266

O. calcareorum endemic 32 32 21 47.6 1.67 2.40 0.198

O. ochotensis – 64 32 21 61.9 2.05 2.69 0.265

O. erecta endemic 48 16 27 44.4 1.56 2.42 0.250

Oxytropis chankaensis Jurtz.

- the outcross pollination by bumblebees, - the capacity for rapid population growth through vigorous seed production, - the long-lived nature of plants,- polyploid origin.

Results show, that genetic variation level in Oxytropis species excepting O. retusa and O. hidakamontana, was rather high as compared with the mean values in other endemic plants (P = 29.9%, He = 0.076, Godt et al., 1996). It may be affected by some specific biological features:

However, among these reasons the polyploid origin of the species, probably, plays the key role. Polyploids are generally characterized by the multiplicity of the enzymes, increased heterozygosity, and allelic diversity, which result from polysomic type of inheritance. This is extremely important for the species existing in small isolated populations, where the effect of gene drift is compensated by "additional" heterozygosity.

of metabolism in a changing environment. Evolutionary success and ecological adaptation of far-eastern Oxytropis species may be directly related to high heterozygosity and enzyme multiplicity.

Schematic representation of electrophoretic variants of dimeric enzyme in diploid (А) and autopolyploid plants (B, C).

Enzyme multiplicity results in enhanced biochemical variability of a plant, and diversity of isoforms can in general improve coordination of metabolic processes, which, in turn, allows polyploids to maintain a high level

Thank you for attention!

We thanks V.Yu. Barkalov and V.P. Verholat, scientific researchers of IBSS FEB RAS, for the plant collection