Tae-Soo Jang

• PhD
• Professor (Assistant) at Chungnam National University

To infer the cytological evolutionary mechanism of the genus Hosta, we analyzed chromosome numbers and karyotypes obtained via Feulgen staining, and measured genome size by flow cytometry. While the chromosome number of all the studied plants was consistently 2n=60, the total haploid chromosome length varied from 55.37 µm in H. jonesii to 76.22 µm...

The genus Juncus L., comprising approximately 310 species, is a perennial herbaceous plant with the highest species diversity among Juncaceae. Although external leaf morphological and anatomical characteristics were used for taxonomic delimitation of Korean Juncus taxa, the micromorphological structure of Juncus is not comprehensively described. Ou...

Interspecific hybridization resulting in diploid-homoploid hybrids is relatively rare in natural populations. The Iris genus, which comprises numerous economically important species, is a taxonomically complex group in which polyploidization and hybridization frequently contribute to taxon diversification and speciation in natural populations. In K...

The new species, Thliphthisa sapphussp. nov. (Rubiaceae, Rubieae), a narrow endemic of the white cliffs of Lefkátas on the southwest coast of Lefkada (Greece) is described and illustrated and an IUCN assessment is presented. Vegetation relevés were performed at the single known locality, limestone cliffs facing the sea and revealed a new associatio...

The genus Disporum (Colchicaceae) comprises approximately 20 species distributed throughout Asia, of which four species (Disporum sessile, D. smilacinum, D. uniflorum, and D. viridescens) are currently recognized in Korea. Mixed-ploidy variations, including odd-ploidy levels within the same species, are important in evolution as they enable backcro...

The genus Ajuga is widely distributed in temperate to subtropical regions, and four species are currently recognized in Korea ( A. decumbens , A. multiflora , A. nipponensis , and A. spectabilis ), but epidermal anatomical differences across these species have never been described. A comparative study of the leaf micromorphological characteristics...

Background Chromosome number and genome size changes via dysploidy and polyploidy accompany plant diversification and speciation. Such changes often impact also morphological characters. An excellent system to address the questions of how extensive and structured chromosomal changes within one species complex affect the phenotype is the monocot spe...

Fluorescence in situ hybridization allows for the mapping of various sequence types in the genomes and is thus widely used in structural, functional, and evolutionary studies. One particular type of in situ hybridization that specifically allows to map whole parental genomes in diploid and polyploid hybrids is genomic in situ hybridization (GISH)....

The segregation of chromosomes depends on the centromere. Most species are monocentric, with the centromere restricted to a single region per chromosome. In some organisms, the monocentric organization changed to holocentric, in which the centromere activity is distributed over the entire chromosome length. However, the causes and consequences of t...

Chromosome number and genome size changes via dysploidy and polyploidy accompany plant diversification and speciation. Such changes often impact also morphological characters. An excellent system to address the questions of how extensive and structured chromosomal changes within one species complex affect the phenotype is the monocot species comple...

Segregation of chromosomes depends on the centromere. Most species are monocentric, with the centromere restricted to a single region per chromosome. In some organisms, monocentric organization changed to holocentric, in which the centromere activity is distributed over the entire chromosome length. However, the causes and consequences of this tran...

Juncus L. (Juncaceae) is a genus of annual and perennial herbs composed of approximately 310 species distributed worldwide, but more rarely found in the tropics. Despite an increasing number of karyological studies in Juncaceae, reports on chromosome numbers in Korean Juncus taxa have been scarce owing to the small chromosome size. Here, we present...

The Iris series Chinenses in Korea comprises four species (I. minutoaurea, I. odaesanensis, I. koreana, and I. rossii), and the group includes some endangered species, owing to their high ornamental, economic, and conservation values. Among them, the putative allotetraploid, Iris koreana (2n = 4x = 50), is hypothesized to have originated from the h...

Rhododendron keiskei var. hypoglaucum (Ericaceae) was recently reported in Korea, with a disjunct distribution on the southern islands of the Korean Peninsula. Although chromosome numbers and ploidy variations are important traits in angiosperms, gaining a clear understanding the cytological features of Rhododendron has been hampered by the small s...

Iris ruthenica Ker Gawl. and I. uniflora Pall. ex Link, which are rare and endangered species in Korea, possess considerable horticultural and medicinal value among Korean irises. However, discrimination of the species is hindered by extensive morphological similarity. Thus, the aim of the present study was to identify discriminating features by co...

Iridaceae L. is a large and well-known plant family that is widely distributed across the northern hemisphere. According to recent and ongoing taxonomic revision, its largest genus, Iris L., includes 14 species of perennial herbs occurring in Korea. Although pollen morphological data have proved crucial to the resolution of systematic relationships...

The genus Iris L., comprising approximately 210 species, is one of the most species‐rich genera in the family Iridaceae. In this study, the first comprehensive leaf micromorphological characters of Korean irises were studied using light and scanning electron microscopy. Our objective was to evaluate the foliar micromorphological characteristics (na...

The genus Cirsium is a member of the tribe Cardueae (Asteraceae) and is distributed in the northern hemisphere. The Carduus-Cirsium group has a long history of taxonomic confusion due to its complicated morphological and molecular phylogenetic data. Here, we report the chromosome numbers and karyotypes of nine currently recognized Korean Cirsium sp...

Changes in chromosome number and karyotype evolution are important to plant diversification, as they are both major drivers of speciation processes. Herein, chromosome number, karyotype, and genome size of the Korean lady’s slipper orchid Cypripedium japonicum Thunb., an endangered species, were investigated in natural populations. Furthermore, all...

The genus Disporum Salisb. is widely distributed in East Asia, yet phylogenetically relevant morphological traits useful for differentiating many of the small, perennial, herbaceous species remain poorly described. To address this, leaf, floral, pollen, and orbicule micromorphology of four Korean Disporum species was investigated using light and sc...

The parasitic genus Cuscuta (Convolvulaceae) is exceptional among plants with respect to centromere organization, including both monocentric and holocentric chromosomes, and substantial variation in genome size and chromosome number. We investigated 12 species representing the diversity of the genus in a phylogenetic context to reveal the molecular...

Chromosome numbers, karyotypes, and genome sizes of 14 Iris L. (Iridaceae Juss.) species in Korea and their closely related taxon, Sisyrinchium rosulatum, are presented and analyzed in a phylogenetic framework. To date, understanding the chromosomal evolution of Korean irises has been hampered by their high chromosome numbers. Here, we report analy...

A comprehensive study on nutlet morphology on 46 taxa from the tribe Elsholtzieae was conducted using stereomicroscopy, light microscopy and scanning electron microscopy. The objectives were to evaluate the nutlet characteristics in a systematics context and to provide additional evidence for taxon delimitation. The nutlet shape varied from ellipti...

The genus Youngia Cass. is taxonomically complex and widely distributed in East Asia. Despite the high diversity of species, only two species, Youngia japonica (L.) DC. and Youngia longiflora (Babc. & Stebbins) C.Shih, are currently found in Korea. Among them, Y. longiflora was once recognized as a subspecies of Y. japonica . However, based on chlo...

The parasitic genus Cuscuta (Convolvulaceae) is exceptional among plants with respect to centromere organization, including both monocentric and holocentric chromosomes, and substantial variation in genome size and chromosome number. We investigated 12 species representing the diversity of the genus in a phylogenetic context to reveal the molecular...

Centromeres are essential for proper chromosome segregation to the daughter cells during mitosis and meiosis. Chromosomes of most eukaryotes studied so far have regional centromeres that form primary constrictions on metaphase chromosomes. These monocentric chromosomes vary from point centromeres to so-called “meta-polycentromeres”, with multiple c...

The Orobanche is the largest group, which are mainly distributed in the northern hemisphere and consisted of about 170 species. The present study is focused on a cytological study on Korean endangered species Orobanche filicicola as well as morphologically similar species O. coerulescens and their morphotype, which was previously referred to O. coe...

The centromere is the region on a chromosome where the kinetochore assembles and spindle microtubules attach during mitosis and meiosis. In the vast majority of eukaryotes, the centromere position is determined epigenetically by the presence of the centromere-specific histone H3 variant CENH3. In species with monocentric chromosomes, CENH3 is confi...

Chromosome number changes and karyotype evolution play an important role in plant genome diversification and eventually in speciation. The genus Ajuga L. of family Lamiaceae has approximately 50 species distributed in temperate to subtropical regions. Four of these species are currently recognized in Korea (A. decumbens Thunb., A. multiflora Bunge,...

Supernumerary chromosomal segments (SCSs) represent additional chromosomal material that, unlike B chromosomes, is attached to the standard chromosome complement. The Prospero autumnale complex (Hyacinthaceae) is polymorphic for euchromatic large terminal SCSs located on the short arm of chromosome 1 in diploid cytotypes AA and B⁷B⁷, and tetraploid...

Polyploidy is a major driving force in angiosperm evolution, but our understanding of establishment and early diversification processes following allo- vs. auto-polyploidy is limited. An excellent system to address such questions is the monocot plant Prospero autumnale, as it comprises several genomically and chromosomally distinct diploid cytotype...

Abstract Allopolyploidy has played an important role in the evolution of the flowering plants. Genome mergers are often accompanied by significant and rapid alterations of genome size and structure via chromosomal rearrangements and altered dynamics of tandem and dispersed repetitive DNA families. Recent developments in sequencing technologies and...

Premise of research. Odontites is an herbaceous genus composed of 27 species, mostly distributed around the Mediterranean Basin. As a first step toward studying species diversification within this genus, our goals were to (i) test previous hypotheses about phylogenetic relationships among species; (ii) assess whether the closely related genera Bart...

Nicotiana sect. Repandae is a group of four allotetraploid species originating from a single allopolyploidisation event approximately 5 million years ago. Previous phylogenetic analyses support the hypothesis of N. nudicaulis as sister to the other three species. This is concordant with changes in genome size, separating those with genome downsizin...

Phylogenetic and molecular clock analyses were performed including all genera except one (Pseudomonotes) for the three subfamilies of Dipterocarpaceae. We also included representatives of Sarcolaenaceae and Cistaceae with Bixaceae as the ultimate outgroup. Three plastid regions (six markers), partial rbcL, trnK-matK-trnK (partial trnK intron includ...

Molecular phylogenetic studies have greatly improved our understanding of phylogenetic relationships of non-photosynthetic parasitic broomrapes (Orobanche and related genera, Orobanchaceae), but a few genera have remained unstudied. One of those is Platypholis, whose sole species, Platypholis boninsimae, is restricted to the Bonin-Islands (Ogasawar...

Glechoma L. (Lamiaceae) is distributed in eastern Asia and Europe. Understanding chromosome evolution in Glechoma has been strongly hampered by its small chromosomes, constant karyotype and polyploidy. Here phylogenetic patterns and chromosomal variation in Glechoma species are considered, using genome sizes, chromosome mapping of 5S and 35S rDNAs...

Molecular phylogenetic studies have greatly improved our understanding of phylogenetic relationships of non-photosynthetic parasitic broomrapes (Orobanche and related genera, Orobanchaceae), but a few genera have remained unstudied. One of those is Platypholis, whose sole species, Platypholis boninsimae, is restricted to the Bonin-Islands (Ogasawar...

Fig. S1 Structure of B chromosomes in 24 of 26 analysed individuals of Prospero autumnale. Fig. S2 Localization of plastid DNA sequences and satellite DNA PaB6 loci in B chromosomes of the Prospero autumnale complex.

Supernumerary B chromosomes (Bs) are genomic parasitic components, originating from the A complement via chromosomal rearrangements, which follow their own evolutionary trajectories. They often contain repetitive DNAs, some shared with regular chromosomes and some newly evolved. Genomic composition, origin and evolution of Bs have been analysed in...

The family Orchidaceae is one of the largest flowering plant families in the world. According to the latest classification of the Orchidaceae, the family encompasses 749 genera under five subfamilies (Apostasioideae, Vanilloideae, Cypripedioideae, Orchidoideae and Epidendroideae). Sri Lanka posses 184 species belonging to family Orchidaceae in 78 g...

Gynodioecy, the phenomenon of having both hermaphrodite and female (i.e. male-sterile) individuals within the same population, is an important intermediate step in the evolution of separate sexes in flowering plants. In this study, we investigated the floral micromorphology and microsporogenesis of the gynodioecious herb Glechoma longituba from fou...

Polyploidy and hybridization play an important role in plant diversification and speciation. The application of genomic in situ hybridization (GISH) allows the identification of parental genomes in hybrids, thus elucidating their origins and allowing for analysis of their genomic evolution. The performance of GISH depends on the similarity of the p...

Plant genomes are dominated by repetitive DNA sequences of many distinct types which, due to their variability and high copy numbers, are difficult to analyse. This sequence complexity has recently become accessible to detailed investigations with the advent of next-generation sequencing technologies and novel analytical approaches utilizing low-pa...

Background and Aims Chromosomal evolution, including numerical and structural changes, is a major force in plant diversification and speciation. This study addresses genomic changes associated with the extensive chromosomal variation of the Mediterranean Prospero autumnale complex (Hyacinthaceae), which includes four diploid cytotypes each with a u...

Alyssum ovirense (Brassicaceae) is disjunctly distributed in the eastern Alps, predominantly occurring in the southern limestone Alps, but with one isolated population on the Hochschwab massif in the northern limestone Alps. The closely related rare and narrow endemic A. wulfenianum is restricted to gravel beds in a few rivers in the southern Alps...

The petal and sepal micromorphology of five species of Glechoma (Lamiaceae) was investigated to evaluate their taxonomic significance, and a molecular phylogeny using the sequences of internal transcribed spacers (ITS) regions of nuclear ribosomal DNA was carried out to resolve their phylogenetic relationships. Stomatal complexes were mostly found...

Reconstruction of the parental origins of cultivated plants from wild relatives, especially after long periods of domestication, is not a trivial task. However, recent advances in molecular phylogenetics, among other approaches, have proved to be very informative in analyses of the origin and evolution of polyploid genomes. An established minor gar...

Prospero (Hyacinthaceae) provides a unique system to assess the impact of genome rearrangements on plant diversification and evolution. The genus exhibits remarkable chromosomal variation but very little morphological differentiation. Basic numbers of x = 4, 5, 6 and 7, extensive polyploidy, and numerous polymorphic chromosome variants were describ...

Polyploidy, the possession of more than 2 complete genomes, is a major force in plant evolution known to affect the genetic and genomic constitution and the phenotype of an organism, which will have consequences for its ecology and geography as well as for lineage diversification and speciation. In this review, we discuss phylogenetic patterns in t...

Pollen morphology of 18 species (32 specimens) representing all three currently recognized sections of the genus Elsholtzia (Elsholtzieae–Lamiaceae) was investigated in detail using light, scanning electron and transmission electron microscopy. Elsholtzia pollen grains are small to medium in size (P=20–50 μm, E=16–45 μm), mostly prolate-spheroidal...

Abstract  The pollen morphology of 13 taxa (34 specimens) of the genera Glechoma L., and Marmoritis Benth. was investigated in detail using light, scanning electron, and transmission electron microscopy. Pollen grains of all studied taxa are small to large in size (P= 32.5–60.4 μm, E= 20.2–50.5 μm), prolate-spheroidal to prolate in shape and mostly...

The petiole anatomy of three sections (sects. Calospira, Chamaedryon, and Spiraria) in the genus Spiraea (Rosaceae), which are distributed/cultivated in Korea, was studied and described in details. The vascular bundle system of the distal, medial, and proximal parts of the petiole were studied using LM with the aim of documenting any differences in...