Notes on genetic variation in Sedum sarmentosum (Crassulaceae): Implications for the origin of southern Korean populations

정미윤,Jordi López-Pujol,정명기 한국식물분류학회 2016 식물 분류학회지 Vol.46 No.4

The succulent herbaceous perennial Sedum sarmentosum commonly grows in the southern part of the Korean Peninsula. It is a species native to China, most likely introduced into Korea due to its edible and medicinal uses. If plants were introduced from a single source, we would expect no or low levels of genetic variation in Korean populations. Alternatively, if plants were introduced from multiple sources, we would expect, in contrast, high levels of genetic diversity. To test which is more likely, we surveyed the degree of allozyme variation in ten populations of this species from southern Korea. We found that S. sarmentosum was monomorphic at all fifteen allozyme loci. However, two congeners (S. polytrichoides and S. kamtschaticum) and two related species (Hylotelephium ussuriense and H. verticillatum) maintain moderate to high levels of genetic diversity (He = 0.144, 0.203, 0.201, and 0.204, respectively). We suggest that southern Korean populations of S. sarmentosum likely descended from a single introduction of a few plants and then became naturalized exclusively via vegetative spreading (as plants in Korea, but also as occurs in other parts of its native and naturalized range, are sterile).

Notes on fine-scale spatial distribution of three Cephalanthera species (Orchidaceae) that grow in sympatry in Korea: Implications for maintenance of species boundaries

정미윤,Jordi López-Pujol,정명기 한국식물분류학회 2017 식물 분류학회지 Vol.47 No.4

The three self-compatible, terrestrial orchids Cephalanthera erecta, C. falcata, and C. longibracteata flower synchronously in sympatric populations. Cephalanthera erecta and C. longibracteata, which have white flowers that do not fully open, are predominantly autogamous, whereas the food-deceptive C. falcata, whose bright yellow flowers open completely, is predominantly outcrossing. The formation of hybrids rarely occurs between species owing to strong prepollination barriers (floral isolation). If these three species have evolved toward the prevention of interspecific hybridization, we can expect that the spatial distribution patterns of the three species would be characterized as spatial segregation (i.e., ‘'spatial repulsion’') from each other. To test this prediction, we studied the three Cephalanthera species in sympatric populations showing coincident flowering within Yeonwhasan Provincial Park (YPP, Gyeongsangnam Province, South Korea). We found strong spatial aggregation in each population and spatial independence in the interspecific spatial distribution, differing from previous studies. We further hypothesize that Cephalanthera species in sympatry within YPP are distributed somewhat randomly in space, perhaps due to the sharing of similar mycorrhizal fungi.

Population genetic structure of Sedum polytrichoides (Crassulaceae): Insights into barriers to gene flow

정미윤,Jordi López-Pujol,정명기 한국식물분류학회 2016 식물 분류학회지 Vol.46 No.4

An area comprising Juwangsan National Park and its adjacent mountains (southeastern Korean Peninsula) is a good model system for testing the effects of physical barriers to gene flows in plant populations. We predicted that plant species consisting of isolated populations are genetically more differentiated than those that are rather continuously distributed. Most populations of Sedum polytrichoides occur in four isolated valleys, and we assessed the genetic variability and structures using twelve allozyme loci in ten populations. We also compared the present results to earlier findings pertaining to the two co-occurring herbs Hylotelephium ussuriense (≡ Sedum ussuriense) (growing only in the four isolated valleys) and S. kamtschaticum (rather continuously distributed). We found moderate levels of within-population genetic variation in S. polytrichoides (He = 0.112). Estimates of among-population divergence in S. polytrichoides were also moderate (FST = 0.250) and, as expected, very similar to that of H. ussuriense (0.261) but considerably higher than the variation in S. kamtschaticum (0.165). An analysis of molecular variance (AMOVA) revealed that S. polytrichoides and H. ussuriense had higher percentages of among-valley variation (19% each) than S. kamtschaticum (4%). Most of this variation, as also indicated by the STRUCTURE program, was due to differences in genetic profiles between the two central valleys. We concluded that the genetic differences observed between species (S. kamtschaticum vs. S. polytrichoides and H. ussuriense) are mainly due to differences in their distribution within the study area.

Is the Baekdudaegan “"the Southern Appalachians of the East”"? A comparison between these mountain systems, focusing on their role as glacial refugia

정미윤,Jordi López-Pujol,정명기 한국식물분류학회 2016 식물 분류학회지 Vol.46 No.4

Based on genetic studies and palaeoecological surveys, the main Korean mountain range, the socalled "Baekdudaegan" (BDDG), has been recently suggested to be a major glacial refugium at the Last Glacial Maximum (LGM) for the boreal and temperate flora of northeastern Asia. On the basis of its shared role as a glacial refugium, and on a series of striking similarities in floristic richness and orographic features, the BDDG would constitute a sort of “"eastern counterpart”" of the Southern Appalachians. Given its floristic, biogeographic, and cultural value, the BDDG merits high priority for conservation.

Lack of allozyme variation in the two carnivorous, terrestrial herbs Utricularia bifida and Utricularia caerulea (Lentibulariaceae) co-occurring on wetlands in South Korea: Inference of population history

정미윤,Jordi López-Pujol,정명기 한국식물분류학회 2017 식물 분류학회지 Vol.47 No.4

In central and southern Korea, the two small insectivorous, terrestrial herbs, Utricularia bifida and U. caerulea, often co-occur at wet locations (or in wetlands). The Korean Peninsula (with central China and northern Japan) constitutes the northern edge of their distribution, as their main range is subtropical and tropical Asia. The Korean populations of both species are very likely of post-glacial origin, given that warm-temperate vegetation was absent from the Korean Peninsula during the Last Glacial Maximum. Two hypotheses of the post-glacial colonization of the peninsula can be formulated; first, if current populations were founded by propagules coming from a single ancestral population (i.e., a single refugium), we would expect low levels of genetic diversity. Alternatively, if contemporary Korean populations originated from multiple sources (multiple refugia), we would expect high levels of genetic variation. To test which is more likely, we surveyed the degree of allozyme variation at 20 loci in ten populations for each of the two species from southern Korea. We found no allozyme variation within each species. However, their aquatic congener U. australis exhibited allozyme polymorphism across Japan (four polymorphic loci at three enzyme systems). We suggest that southern Korean populations of Utricularia bifida and U. caerulea were established by a single introduction event from a genetically depauperate ancestral population.

Genetic diversity in the common terrestrial orchid Oreorchis patens and its rare congener Oreorchis coreana: inference of species evolutionary history and implications for conservation.

Chung, Mi Yoon,L?pez-Pujol, Jordi,Maki, Masayuki,Kim, Ki-Joong,Chung, Jae Min,Sun, Byung-Yun,Chung, Myong Gi published for the Association by Oxford University 2012 The Journal of heredity Vol.103 No.5

<P>We hypothesized that the main Korean mountain ranges provided many refugia for boreal plant species, where they likely found relatively stable habitats and maintained large population sizes. Under this scenario, high levels of genetic variation and low degree of differentiation among populations within these species were anticipated. To test this hypothesis, we examined levels of allozyme diversity (17 loci) in 12 populations of the common terrestrial montane orchid Oreorchis patens from the main ranges in Korea and 4 populations of its rare congener O. coreana, which is restricted to the Korean island of Jeju. As expected, O. patens harbored high levels of genetic variation within populations (%P = 62.8, A = 1.96, H (o) = 0.211, and H (e) = 0.237). Allele frequency differences among populations were low (F (ST) = 0.075), and the species also displayed a significant correlation between pairwise genetic differentiation and geographical distance. All these results suggest that extant populations were founded by multiple genetically diverse individuals and that most of this initial diversity would have been maintained in the stable mountainous conditions during Quaternary climatic oscillations. In contrast, we were unable to detect any genetic diversity in O. coreana, suggesting that contemporary populations likely originated from a single ancestral source population that had lost all genetic variability. From a long-term conservation genetics perspective, extreme rarity and small population sizes, coupled with its apparent genetic uniformity, place O. coreana at a high risk of extinction. Thus, both in situ and ex situ conservation efforts should be of particular importance for this species.</P>

Comparative genetic structure between <i>Sedum ussuriense</i> and <i>S. kamtschaticum</i> (Crassulaceae), two stonecrops co-occurring on rocky cliffs

Chung, Mi Yoon,Ló,pez-Pujol, Jordi,Chung, Myong Gi Botanical Society of America 2014 American journal of botany Vol.101 No.6

<P>• <I>Premise of the study:</I> Geographic isolation due to discontinuities of suitable habitat may have significant effects on the genetic structure of plant populations. Even within a few kilometers, physical barriers to gene flow may lead to considerable genetic differentiation among populations.</P><P>• <I>Methods: Sedum ussuriense</I> is a boreal species that in Korea occurs only in four valleys separated by mountain ranges in Juwangsan National Park and its vicinity (a range of ∼15 km). Its congener <I>S. kamtschaticum</I>, by contrast, co-occurs in the four valleys but also on the intervening mountains. Using 12 allozyme loci, we comparatively assessed genetic variability and structure in 12 population pairs of the two stonecrops.</P><P>• <I>Key results:</I> While we found high and comparable levels of within-population genetic variation for the two species, among-population divergence was significantly higher in <I>S. ussuriense</I> (<I>F</I><SUB>ST</SUB> = 0.261 vs. <I>F</I><SUB>ST</SUB> = 0.165). <I>Sedum ussuriense</I> also showed a much higher percentage of among-valley variation (19%) than <I>S. kamtschaticum</I> (4%).</P><P>• <I>Conclusions:</I> High levels of genetic diversity in the two <I>Sedum</I> species are consistent with the previous hypothesis that mountains of the Korean Peninsula served as glacial refugia for many boreal species. Given that the two congeners have similar life-history traits, the lower among-population differentiation in <I>S. kamtschaticum</I> is attributable to its higher abundance and more continuous distribution in the study area. This study confirms the central role of geographic isolation in the genetic structure of plant species even at very small scales.</P>

Clonal and genetic structure of Iris odaesanensis and Iris rossii (Iridaceae): insights of the Baekdudaegan Mountains as a glacial refugium for boreal and temperate plants

Chung, Mi Y.,Ló,pez-Pujol, Jordi,Lee, You M.,Oh, Seung H.,Chung, Myong G. Springer-Verlag 2015 Plant systematics and evolution Vol.301 No.5

Contrasting Levels of Clonal and Within-Population Genetic Diversity between the 2 Ecologically Different Herbs <i>Polygonatum stenophyllum</i> and <i>Polygonatum inflatum</i> (Liliaceae)

Chung, Mi Yoon,Ló,pez-Pujol, Jordi,Chung, Jae Min,Kim, Ki-Joong,Chung, Myong Gi The American Genetic Association 2014 The Journal of heredity Vol.105 No.5

<P>Comparative studies on clonal and genetic structure between ecologically contrasting congeners may provide valuable insights into the mechanisms promoting the maintenance of genetic diversity in clonal plant species. <I>Polygonatum stenophyllum</I> has long rhizomes (ca. 30–40cm long) and largely occurs on sandy soils in open river banks, whereas its congener <I>Polygonatum inflatum</I> has short ones (ca. 5–10cm long) and occurs on humic soils under deciduous forests. Using 21 allozyme loci, we comparatively assessed levels of clonal and genetic diversity in the 2 clonal species. Seven populations of <I>P. stenophyllum</I> consisted of single clones, and levels of within-population clonal and genetic variation were considerably lower than those of <I>P. inflatum</I>. However, when samples were pooled, <I>P. stenophyllum</I> harbored higher genetic variation than <I>P. inflatum</I>, which is due to higher among-population genetic differentiation in the former species compared with the latter (<I>F</I> <SUB>ST</SUB> = 0.636 vs. <I>F</I> <SUB>ST</SUB> = 0.165). Our data suggest that populations of <I>P. stenophyllum</I> have been mainly founded by a single seed or rhizome (through river water) or by a few seeds, whereas populations of <I>P. inflatum</I> would have been established through multiple, repeated seedling recruitment. Moderate levels of genetic diversity in a population of <I>P. stenophyllum</I> located at the foot of the Baekdudaegan Mountains and in all the populations of <I>P. inflatum</I> are consistent with the previous hypothesis that these mountains served as a glacial refugium for many boreal species of the Korean Peninsula.</P>

The role of the Baekdudaegan (Korean Peninsula) as a major glacial refugium for plant species: A priority for conservation

Chung, Mi Yoon,Ló,pez-Pujol, Jordi,Chung, Myong Gi Elsevier 2017 Biological conservation Vol.206 No.-

<P><B>Abstract</B></P> <P>The main Korean mountain range [the so-called “Baekdudaegan” (BDDG)] is thought to have served as a glacial refugium, mainly for the boreal and temperate flora of northeastern Asia. To test this hypothesis, we have critically reviewed (<I>i</I>) the genetic literature focused on plants for which Korean populations have been studied or Korean endemic plants, and (<I>ii</I>) palaeoecological studies with data from the Korean Peninsula and/or from neighboring regions. Consistent with this hypothesis, Korean populations showed higher intrapopulation genetic diversity (and, in some cases, with latitudinal decreases of genetic variation), harbored ancestral haplotypes, and/or exhibited significant amounts of unique haplotypes/alleles. Palaeoecological data support the genetic studies, indicating that the BDDG sustained an assemblage of boreal and temperate forests at the Last Glacial Maximum (LGM). Given its floristic, biogeographic, and cultural value (it is regarded as a “holy mountain system” in Korea), the BDDG merits high priority for conservation. In order to guarantee the preservation of the BDDG, we suggest enlarging the current BDDG Mountains Reserve in South Korea, whereas in North Korea the accelerated deforestation should be stopped and new protected areas should be set up. Cooperation between the two Koreas is also needed, and may constitute an important step towards more ambitious initiatives such as the creation of the “Ecological Corridor of Northeast Asia”.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The main Korean mountain range (“Baekdudaegan”, BDDG) is thought to have served as a major glacial refugium for plants. </LI> <LI> Phylogeographic and palaeoecological studies support the hypothesis of the BDDG as a plant refugium. </LI> <LI> The BDDG merits high priority for conservation also because of its floristic and cultural value. </LI> <LI> Cooperation between the two Koreas is needed to guarantee the preservation of the BDDG. </LI> </UL> </P>