Genetic Diversity in Some Oxytropis Species in the North-East Asia

1
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
2
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.
3
Chromosome number, geographic range and sampling
site locations for Oxytropis species
Section Arctobia O. 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
Orobia O. 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 Baicalia O. chankaensis Jurtz., endemic,
2n 32. Primorye, Khanka Lake, Sosnovyi Island.
Oxytropis revoluta Ledeb. Photo by S.K. Kholin
Oxytropis retusa Matsum. Photo by V.Yu. Barkalov
4
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.
Electrophoretic patterns of some polymorphic loci
of Oxytropis chankaensis
5
Allozyme variation parameters in examined
Oxytropis species
Species Status 2n N Number of 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. retusa endemic, 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. kamtchatica endemic, rare 16 27 30 43.3 1.67 2.54 0.199
O. chankaensis endemic, 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
O. ochotensis 64 32 21 61.9 2.05 2.69 0.265
O. chankaensis endemic, 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.
6
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

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

Oxytropis chankaensis Jurtz.
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.
7
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
Schematic representation of electrophoretic
variants of dimeric enzyme in diploid (?) and
autopolyploid plants (B, C).
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.
8
Thank you for attention!
We thanks V.Yu. Barkalov and V.P. Verholat,
scientific researchers of IBSS FEB RAS, for the
plant collection